Digital domain content processing and distribution apparatus and methods

Abstract

Methods and apparatus for distributing content using a spectrum generation device. In one embodiment, digital content is received via a time-multiplexed network transport (such as Gigabit Ethernet), and converted to frequency channels suitable for transmission over a content distribution (e.g., Hybrid Fiber Coaxial (HFC)) network. In one variant, the conversion is performed using digital domain processing performed by a full spectrum generation device. Additionally, methods and apparatus for selectively adding, removing, and/or changing digital content from the full spectrum device are also disclosed. Various aspects of the present invention enable physical (infrastructure) consolidation, and software-implemented remote management of content distribution.

Description

timeDomain Division Multiplexing (TDM) data streams from multiple source devices to Frequency Domain Division Multiplexing (FDM) data streams consumed at multiple sink devices (e.g., CPEs). The unified edge device receives a number of input data streams via e.g., a Gig-E (Gigabit Ethernet) backbone, and transmits the entire cable spectrum (e.g., 54 MHz-1 GHz). The cable spectrum may be provided in RF, or direct laser output (for optical coupling). A single edge device can generate the entire frequency spectrum for supporting multiple subscriber “narrowcast” services e.g., Digitized Analog, Digital, Video-On-Demand (VOD), Switched Digital Video (SDV), High Speed Data (HSD), etc. The desired services (for the group of subscribers) are received at the edge device, converted to the frequency time domain, and combined to form the entire spectrum transmitted to the served subscribers. Different modulation types (e.g., QAM, QPSK, etc.) are supported for the different services as needed.

Physical Consolidation—

As will be readily appreciated the exemplary edge device substantially reduces (or eliminates) combining, cascading, splitting, mixing, etc. of the type performed under prior art implementations. Hardware for cascading, combining, filtering, etc. can consume tremendous amounts of RF energy, as well as space, electrical power, and other resources. Elimination of these intermediate stages greatly improves power consumption, while also reducing the physical/hardware “footprint” needed to provide equivalent service. Also, consolidation of spectrum generation within a single entity greatly reduces the wiring or cabling necessary. Less wiring corresponds to further reductions in power consumption, and minimizes human error (e.g., mis-wiring, faulty wiring, etc.). Power considerations directly impact space, cooling requirements and other physical restrictions. For example, one exemplary embodiment of the edge device described herein consumes on the order of 0.5 (point five) Amps, and occupies roughly one-half of a hubsite server Rack Unit (RU). Hence, very significant space and power savings are realized as compared to the prior art previously discussed herein (i.e., up to 2 (two) Amps and 20 (twenty) full racks).

Moreover, fewer components and cables generally translate to less opportunity for component failure, and hence enhanced reliability.

Furthermore, the reduction of intermediate stages greatly improves signal quality. The spectrum generated by the edge device has, significantly higher fidelity than equivalent prior art structures. Prior art solutions for removing or adding narrowcast content required multiple intermediate stages for removing existing QAMs, adding new QAMs, etc.; each intermediate stage cumulatively adds additional noise. In contrast, the edge device described herein generates the entire spectrum directly from the digital content; the signal integrity is completely preserved, since there are no intermediate “analog” operations (e.g., combining, mixing, splicing, etc.).

Software-Based Support—

In addition to the various physical advantages of edge device augmented networks, in one embodiment of the present invention, each edge device comprises a reconfigurable fabric for software programmable operation. Such reconfigurable fabric may be implemented for example using one or more Field Programmable Gate Arrays (FPGAs) or other Programmable Logic Devices (PLDs), or Reconfigurable Compute Fabrics (RCFs). Other variations may be virtualized within a multitude of dedicated processors, such as DSPs (Digital Signal Processors) or processor cores, Fast DACs (Digital to Analog Converters etc.

Consider traditional network “edges”; modifications to hub sites might range from changing service offerings to subscribers, to feature upgrades. In either case, technicians must be deployed physically to the hub site or other location to rewire the affected rack units. Further, in some cases, new hardware and software must be installed. Unfortunately, manual configuration is a time consuming, expensive and error prone process.

The edge device software configurability of the edge device of the invention has very significant implications for network maintenance and upkeep costs. Perhaps most notably, the edge device can be reconfigured entirely in software. For example, changing a standard definition (SD) channel to a high definition (HD) channel could be performed with a firmware update. Similarly, adding a new content source (e.g., VOD, SDV, etc.) might entail changing or adding an entry for the content source's network address.

In addition to being virtually instant and resistant to human error, reconfiguration can advantageously be performed remotely. Streamlined updating may be performed for the entire cable network, from any authorized network terminal (e.g., one disposed at the headend). Network management provides other flexible upgrade possibilities not previously possible; for example, one edge device could incorporate content from multiple devices maintained in remote facilities, where the content is specified entirely by network address. Such networked content may be leveraged to flexibly support unexpected “overflow” conditions, various demographics or geographies, or even trial installations.

Additionally, in certain embodiments, reconfiguration can be made entirely automated. Unlike manual procedures which require human upkeep and execution, automated reconfiguration may be useful to respond to certain “trigger” conditions, or efficiently shift resource allocations to satisfy real-time subscriber preferences. For example, unexpected peaks of demand for content can trigger automatic reconfiguration of resource allocations or service groups, without requiring technician intervention. This approach also helps provide enhanced network robustness to varying and unpredictable operating conditions, in that the network is dynamically adaptive and substantially “self healing”.

Edge Device-Based Network Architectures—

The edge device augmented network can receive a number of input data streams via e.g., a Gig-E (Gigabit Ethernet) backbone from multiple content sources within a content delivery network, and generate the entire frequency spectrum for a population of CPE. The exemplary edge device network is thus substantially “flattened” in comparison to typical hierarchical networks which use multiple stages of analog components to insert, mix, or remove channels in the analog domain. As previously described, since the entire spectrum is generated directly from the digital content, the introduction of noise from analog elements is reduced and/or nullified. The inventive network is truly “all digital” in terms of content processing.

FIG. 2a illustrates an exemplary content processing and distribution scheme 200 for one exemplary service group comprising a number of CPE in accordance with the present invention. As shown in FIG. 2a, a full spectrum edge device 204 receives time-multiplexed content 206 from a number of content sources 208, and generates the comprehensive spectrum 210 for a plurality of tuners 202 served by the service group. While the following discussions are described within a TDM-to-FDM based system, the multiplexing method is a design selection for one exemplary network implementation, and is not a required to practice the present invention. For example, in alternate embodiments, the full spectrum edge device may receive FDM streams and produce TDM outputs. Similarly, the full spectrum edge device may receive FDM streams and regenerate new FDM streams, or juggle scheduling for a number of TDM inputs to TDM outputs.

Moreover, it is appreciated that other multiplexing schemes may be used given the contents of the present disclosure. For example, current cable networks incorporate fiber optic cabling which use coarse wave division multiplexing (CWDM) schemes. CWDM is one variant of a family of wave-division multiplexing (WDM) technologies which multiplexes multiple signals using different wavelengths of light for each signal. Other WDM technologies include dense wave division multiplexing (DWDM), Ultra DWDM, etc. Thus, certain fiber optic embodiments of the present invention are adapted to convert multiple TDM streams to CWDM streams for transmission over fiber optic cabling.

FIG. 2b illustrates one exemplary embodiment of a “flattened” network architecture employing the edge device 204. As shown, the network architecture 250 is generally comprised of a headend 252, a content transport portion 254, a plurality of hubsites or other distribution nodes 256, and a plurality of served CPE 106. In various implementations, the transport portion may comprise any number of different components and transport modalities. For instance, in one embodiment, the transport 254 comprises a Gigabit Ethernet (Gig-E) backbone of the types well known in the networking arts.

The Gig-E backbone is already resident in many extant cable and other network architectures, and hence can be used for packet-switched delivery of content to the various hubsites. For instance, the Gig-E backbone can carry one or more multiplexed content streams (somewhat akin to an MPTS, yet over the Gig-E packet switched domain and without an underlying MPEG container). These common streams can be broadcast (e.g., to all hubsites), or multicast (i.e., only to specific hubsites), or even unicast to one destination as desired, and accordingly may be heterogeneous or homogenous in terms of content carried.

In another embodiment, the transport portion may comprise one or more optical networks (e.g., CWDM, DWDM, Ultra DWDM, etc.) and other portions of the extant cable plant to distribute the multiplexed stream(s) to the various hub sites.

In yet another embodiment, a circuit-switched network could be used to carry the content to the various hubsites; e.g., Asynchronous Transfer Mode (ATM). As is well known, ATM employs 53-byte packets for payload delivery, yet carries these packets via logical pathways and circuits called VPIs and VCIs respectively.

As a further alternative, a wireless transport might be used; e.g., WiMAX (IEEE Std. 802.16) or millimeter wave system, or even satellite.

Disposed at each hubsite 256 are one or more full spectrum edge devices 204 of the type previously described. These devices: (i) demultiplex the time-multiplexed content streams delivered over the transport 254 into individual program streams; (ii) assign or allocate each of the program streams to a frequency resource (note that multiple program streams may be 25 assigned to the same resource if desired), and (iii) perform conversion of the streams to the frequency time domain using e.g., an IFFT operation or other domain transformation. The edge device is configured with sufficient processing power (described below) to generate all portions of the requisite frequency spectrum simultaneously, in one variant using a plurality of parallel IFFT “engines” which can perform the requisite IFFT calculations at high speed to support the domain transformation of large amounts of data (approximately 6.2 Gbps; i.e., 160 channels multiplied by 38.8 Mbps per channel) of streamed content.

CPE 106 (e.g., digital STBs, etc.) equipped with an RF tuner can tune to the appropriate portion of the generated spectrum to receive and demodulate the program stream of interest, akin to a normal STB arrangement. For example, current cable networks dedicate an additional channel for carrying system information (e.g., current programming information, etc.). Exemplary embodiments provide a dedicated QPSK (Quadrature Phase Shift Keying) modulated channel; this control channel provides system data via well known protocols e.g., ALOHA access protocols (e.g., pure ALOHA, slotted ALOHA, etc.), and DAVIC (Digital Audio Video Council) protocols, although it will be appreciated that other approaches may be used consistent with the invention.

In some embodiments, the full spectrum edge device 204 aligns itself with received system information. For example, the full spectrum device may receive current programming information from a higher network entity. After programming its internal channel interfaces, the full spectrum edge device provides the resultant spectrum, and the accompanying control channels to the service group, consistent with the received system information.

In alternate embodiments, the full spectrum edge device 204 generates the control channel internally, based on its internal operations. For example, the full spectrum device may dynamically assign program streams to various frequency resources. Thereafter, the full spectrum edge device also generates the programming information, such that its serviced CPEs can track current programming, transparent to the customer. In one such example, the full spectrum edge device can flexibly assign content to any number of channels; the CPE is notified (via control channel) of current programming. When the customer selects content of interest, the CPE references its internal record (which matches content to channels), and accesses the proper channel.

While the foregoing network architectures described herein can (and in fact do) carry packetized content (e.g., IP over MPEG for high-speed data or Internet TV, MPEG2 packet content over QAM for MPTS, etc.), they are often not optimized for such delivery (i.e., an all-IP model). Hence, in accordance with another embodiment of the present invention, a “packet optimized” delivery network is used for carriage of the packet content (e.g., IPTV content). FIG. 2c illustrates one exemplary implementation of such a network, in the context of a 3GPP IMS (IP Multimedia Subsystem) network with common control plane and service delivery platform (SDP), as described in U.S. provisional patent application Ser. No. 61/256,903 filed Oct. 30, 2009 and entitled “METHODS AND APPARATUS FOR PACKETIZED CONTENT DELIVERY OVER A CONTENT DELIVERY NETWORK, incorporated herein by reference in its entirety. This architecture makes pervasive use of IP-protocol content of all types (i.e., high speed data, IPTV content, etc.), with IP being the common network protocol so as to permit various types of functions including converged services and platforms, mobility, high service velocity, etc.

In the case of the edge device of the present invention, the multiplexed content stream received at each hub site may be encapsulated within an IP “wrapper” (as well as its native lower layer protocol; e.g., Gig-E), akin to IP-packetized content being carried over an Ethernet LAN, Wi-Fi bearer, etc. In some embodiments of the present invention, the multiplexed content stream is transmitted by the edge device “as is”; i.e., the encapsulated content is transmitted in encapsulated form to the subscriber CPE, service group, etc. In alternate embodiments, the multiplexed content is extracted and transmitted. In some variants, the extracted content may be re-encapsulated with a new IP wrapper, or otherwise re-coded for transmission.

One exemplary delivery paradigm using the network of FIG. 2c comprises delivering MPEG-based video content, with the video transported to user PCs (or IP-based DSTBs) over the allocated portion(s) of the frequency spectrum comprising MPEG (or other video codec such as H.264/AVC) over LP over a container (e.g., MPEG). That is, the higher layer MPEG-2, H.264 or other encoded content is encapsulated using an IP protocol, which then utilizes an MPEG packetization of the type well known in the art for delivery over the RF channels.

Those of ordinary skill in the related arts will readily appreciate the benefits of the present invention and the potential future innovations in content distribution networks enabled therefrom. For example, in the aforementioned all IP network, consider a hubsite that supports DOCSIS 3.0 for a prototype consumer audience (e.g., twenty (20) service groups). As deployment matures over time, the number of service groups will increase in size and shrink in number of consumer's serviced, conceivably until each CPE has a personal service group (several hundred). Using prior art rollout methods, each new service group requires rewiring, restacking, etc. In contrast to prior art solutions, one embodiment of the present invention can be dynamically and remotely reprogrammed to adjust its operation according to this model.

FIG. 2d illustrates a first embodiment of a high-level network architecture according to the invention. As shown, a plurality of content signal sources 262 feed a transport network (e.g., GigE) 254, which supplies input to the SGD stage having a plurality of SGDs 204. The embodiment of FIG. 2d notably utilizes a direct laser (optical domain) output from the SGD 204 into the downstream network and narrowcast service groups 266. A 1-to-1 laser-to-node ratio is utilized in this embodiment, although other ratios (e.g. 1-to-N) may be utilized consistent with the invention. The SGD outputs modulated digitized analog, as well as digital broadcast, SDV, VOD, RF two-way, and DOCSIS 1.0 and 3.0 signals in the optical domain. These optical domain signals are then converted to the RF domain via one or more optical-RF couplers 264 of the type well known in the networking arts. Delivery to the tuners 202 of the premises is then effected via normal RF transport (e.g., indigenous cable plant infrastructure). Alternatively, delivery to the premises may utilize FTTx (e.g., FTTH, FTTC or the like) optical fiber delivery.

In contrast, the architecture of FIG. 2e utilizes an RF domain output from the SGDs 204 to one or more RF combiners 265, and then to the respective service groups 266.

In the embodiment of FIG. 2f, an RF output from the SGDs 204 is utilized (and one or more RF combiners 265, as in the embodiment of FIG. 2e); however, the two-way RF communications 267 and DOCSIS functionality 28 268, 269 are removed from the SGD 204, and provided via separate functionality (e.g., through existing CMTS).

FIGS. 2g-2j illustrate various content and signal flows within the generalized architectures of FIGS. 2d-2f. The various components of the illustrated architecture include: (i) one or more receivers 274 which provide satellite acquisition; (ii) one or more encoders 275 that convert analog signals to digital; (iii) one or more clampers 276 which convert digital variable bitrate (VBR) signals to constant bitrate (CBR) or “clamped” signals; (iv) one or more MPEG overlay entities 277, which provide bulk graphics and video overlay of MPEG (e.g., EAS); (v) one or more VOD servers 105 which provide CBR MPEG streaming engines for Movies On Demand (MOD) or On Demand (OD) content; (vi) one or more DPI servers 272 which provide CBR MPEG streaming engines for advertisement and other secondary content insertion; (viii) one or more splicers 278 that insert advertisements and other secondary content into program streams; (ix) one or more network encryptors 279 or session encryptors 281 that apply encryption to digital signals; (x) one or more “bulk” statistical multiplexers 280 that optimize digital channel loading via statistical multiplexing processes; and (xi) one or more SGDs 204 as previously described, which are in the exemplary configuration TDM-to-FDM transformers.

Specifically, FIG. 2g illustrates analog broadcast signal flow, from one or more sources 270 and via a digital program insertion (DPI) server 272. A bulk overlay (e.g., EAS) is applied to the unencrypted single program transport stream (SPTS) multicast, and the resulting signals sent to the SGD 204 for conversion to the frequency time domain as previously described.

FIG. 2h is a logical block diagram illustrating the signal flow for VOD content delivery within one exemplary architecture of the network. As shown, the content resident on the VOD server 105 is streamed as an unencrypted SPTS to a session encryptor 281 for encryption. The encrypted content is then converted by the SGD 204 to the frequency time domain, and distributed as a unicast to the relevant service group for delivery to the requesting CPE.

FIG. 2i is a logical block diagram illustrating the signal flow for VOD with “start-over” functionality within one exemplary architecture of the network. As shown, the content is ingested from one or more sources, and the DPI server 272 inserts advertisements or other secondary content to form an unencrypted SPTS multicast. This SPTS is provided to a scheduler 282 (e.g., such as the exemplary Sectamus device of the Assignee hereof). The automated scheduler 282 provides pagination (i.e., segmenting of the continuous incoming broadcast streams into program files) and implements business rules for the content and determines which programs will be passed to the VOD system and written to storage. The scheduler may also be configured to apply the appropriate metadata content (title, rating, starring actors, etc.) to the program as it is being prepared for “start-over” delivery. The VOD server then streams the SPTS unicast to the session encryptor 281 for encryption, and then the SGD 204 for transformation and delivery as a unicast.

FIG. 2j is a logical block diagram illustrating the signal flow for switched (e.g., SDV multicast) content delivery within one exemplary architecture of the network. As shown, the content is ingested from one or more sources and converted to digital domain as required by the encoder 275, and clamp the VBR signal to a CBR using the clamper(s) 276. The DPI server 272 inserts advertisements or other secondary content to form an unencrypted SPTS multicast. The unencrypted SPTS multicast is then provided to the bulk (network) encryptor 279, where it is encrypted and provided to the SGD 204 for transform and multicast distribution.

Spectrum Allocation—

FIG. 3 is a representation of one prior art RF spectrum 300. Current North American cable television frequency spans from 54 MHz to 1 GHz. As shown, the prior art implementations intermix channel allocations across the bandwidth using comb insertion filters, splicing, mixing, etc. For example, HSD 312, HD 306, SDV 310 and VOD 308 services are “shoehorned” into available channels. Certain higher bandwidth applications prefer contiguous and/or adjacent bandwidths. The highly heterogeneous allocations are difficult to modify; for example, changing the allocations for resources, or moving channels affects many other channels. Similarly, block up-conversion for narrowcast QAMs can further complicate channel calculations; up-conversion requires adjacent 6 MHz slots in blocks of 2, 4, 8, 12, or 16.

In contrast to the prior art spectrum of FIG. 3, FIG. 4 illustrates several possible spectrum allocations according to the present invention, corresponding to different software configurations. Consider a first software configuration 410, which has neatly aggregated different content types together. As shown, analog channels 302, digital channels 304, High Definition (HD) channels 306, Video on Demand (VOD) channels 308, Switched Digital Video (SDV) 310, and High Speed Data (HSD) 312 are grouped together (the illustrated configuration is simplified for purposes of illustration).

A second software configuration 420 has a different spectrum allocation from the first spectrum. As shown, more channels are allocated for HD 306, VOD 308, SDV 310, HSD 312, and analog channels 302 are reduced.

Similarly, a third software configuration 430 juggles the various allocations arbitrarily (HD has been swapped with analog channels, VOD and SDV have also been swapped). In fact, a myriad of possible software configurations can be used to control the appropriate network utilization. Channel allocations can be dynamically reprogrammed to easily accommodate on-the-fly block up-conversion, channel juggling, and changes to service offerings.

In contrast to prior art network management, various embodiments of the present invention control spectrum allocation with software configuration. Changes to spectrum allocation are resolved in software (e.g., updating a configuration file, changing operational parameters, etc.). Similarly, embodiments of the present invention do not require any rewiring or rerouting of hardware at the hub site or otherwise; instead, configuration changes are software updates that parameterize the conversion from digital content to individual frequency channels.

Edge Device Apparatus—

FIG. 5 is a graphical representation of one exemplary implementation of a full spectrum edge device 204 according to the invention. The device 204 includes a network interface 502, a processor subsystem 504 and its associated storage 506, a programmable substrate 508, and a downstream interface 510 for delivering content to recipient devices (e.g., CPEs 202). Each of these components is described in greater detail subsequently herein.

The device 204 of FIG. 5 is merely representative of features and operations of a full spectrum edge device, and design or configuration changes necessary for other network technologies are readily appreciated by those of ordinary skill given the present disclosure.

The illustrated device 204 can assume literally any form factor. One exemplary embodiment is adapted for rack use. Alternate embodiments may be integrated in whole or part (e.g., on a common functional basis) with other devices if desired.

Network Interface—

In one embodiment, the network interface 502 of the edge device schedules and/or receives subscriber content for transmission. The network interface may queue data, receive streaming data, handle just-in-time reception of content, etc. In one variant, the subscriber content is received from one or more data sources via the network interface. The data sources may generate the content locally, or alternatively act as a gateway or intermediary from another distant or third party source. Examples of such data sources may include other networked servers for Digitized Analog, Digital, Video-On-Demand (VOD), Switched Digital Video (SDV), High Speed Data (HSD), etc.

In the following discussions, a packet-switched network interface is disclosed in detail. In alternative embodiments, the network interface may be circuit-switched. Packet-switched data delivery has unpredictable hops, and variable delays; however, packet-switched networks efficiently allocate network bandwidth, and flexibly resolve network congestion. In contrast to packet-switched networks, circuit-switched networks maintain dedicated connections of constant bit rate and constant delay between nodes. Circuit-switched networks may also carry packetized data (e.g., ATM with VPI/VCI). Circuit-switched networks are generally reliable, but also generally less efficient. The tradeoffs and design considerations for circuit-switched and packet-switched networks are well understood within the relevant arts; modifications to the present invention for use with circuit-switched networks are well within the skill of the ordinary artisan, given the contents of the present disclosure.

In the previously described exemplary embodiment of FIG. 2, the network interface 502 is based on a Gigabit Ethernet (Gig-E) interface. Gig-E is a packet-switched technology, i.e., blocks of data are sent and received via a “cloud” of connections within a network. Each networked device is given a unique MAC (Medium Access Control) address, and routing is performed on a hop-by-hop basis (MAC addresses are included in every data packet to specify both the destination and the source of each data packet). In Gig-E networks, data packets are encapsulated within a “frame”. The frame may also include physical layer components such as a preamble, and flow control characters.

The Gig-E interface receives content from multiple sources 208. Each of the content sources provides content in a time-multiplexed manner. Time-multiplexing refers to providing multiple sources of information in a time scheduled manner. For example, common embodiments use a round robin schedule, where each source takes turns on the connection. The time domain is divided into timeslots. Thus, during the first timeslot, the first source has a connection, etc. Time slots may be allocated on a recurrent, single shot, opportunistic, etc. basis. Various sources may have different levels of priority. Other time-multiplexing schemes are well known throughout the related arts, and accordingly not described further herein.

In some variants of the present invention, the network interface 502 additionally comprises one or more buffer queues, suitable for buffering data delivery. In some implementations, the buffer is filled and then consumed; alternately, the buffer may be filled and consumed simultaneously. Furthermore, in certain applications, the buffer may be oversized to provide additional overrun protection (i.e., rate of consumption out paces the rate of filling). Flow control may also be imposed by the interface (e.g., using pause frames or stop packets, throttling, etc.) where needed in order to control the flow of data from one or more sources.

Generally, real-time streaming multimedia applications (such as video) may be highly sensitive to bit rates, and/or delay. Thus, in one embodiment of the present invention, the network interface 502 communicates Quality of Service (QoS) parameters with its data sources 208, or other network management entity. QoS provides traffic management priorities to different applications, users, or data flows, or to guarantee a certain level of performance. QoS parameters may control bit rates, delay, jitter, packet dropping probability, bit error rates, etc. One exemplary scheme employs the well known RTP/RTCP (Real-Time Transport Protocol/RTP Control Protocol) protocols for this QoS function, although it will be appreciated that other schemes and protocols may be used with equal success.

In one embodiment, the network interface 502 is also coupled to an optional processing subsystem 504, and programmable substrate 508; the coupling enables network configuration and programming (e.g., device control) therefrom, as described in greater detail subsequently herein.

The network interface 502 can be configured to selectively connect to one or more external data content devices 208. In one exemplary embodiment, the network interface can selectively couple to one or more broadcast services, and one or more narrowcast services. In one variant, the connections are dynamically determined with a processing subsystem 504 executing one or more business and/or operational optimizations. In an alternate variant, the connections are remotely set via a centralized network management entity. In yet another alternate variant, the connections are hardcoded into a removable device, such as a hot-swappable card, computer readable memory media, etc.

In some embodiments of the edge device, the network interface 502 is a wireless interface. For example, in one embodiment, the network interface is associated with the Worldwide Interoperability for Microwave Access (WiMAX) transport; see IEEE Std. 802.16e-2005 entitled “IEEE STANDARD FOR LOCAL AND METROPOLITAN AREA NETWORKS—PART 16: AIR INTERFACE FOR FIXED AND MOBILE-BROADBAND WIRELESS ACCESS SYSTEMS AMENDMENT 2: PHYSICAL AND MEDIUM ACCESS CONTROL LAYERS FOR COMBINED FIXED AND MOBILE OPERATION IN LICENSED BANDS”, and subsequent variants thereof, including e.g., 802.16-2009, which are incorporated herein by reference in their entirety. In another variant, a millimeter wave system, WirelessHD, WiGIG, or satellite downlink is utilized. Wireless embodiments may find particular use areas where cabling may be difficult or even impossible to support. For example, mobile embodiments (such as a cruise ship, train, or plane) may receive both live content via satellite, and “canned” content (e.g., ship specific programming) for use within a scaled-down version of the edge device (described hereinafter).

Encryption of the network interface link is network-specific (e.g., based on the platform, network/MSO, payload, etc.), and may be handled external to the device or alternately, internalized within the processing subsystem 504 (i.e., fixed encryption networks, etc.). Thus, some network interfaces may require additional encryption/decryption capabilities. In one exemplary embodiment, the full spectrum edge device relies on external devices for broadcast, common-tier, and session-based encryption. In one such variant, encryption is handled with “bulk encryption”; i.e., the entire payload is encrypted by an encryption engine. In other variants, encryption may be based on interface-specific considerations, thereby providing support for encryption protocol flexibility (e.g., legacy and future standards, external and internal encryption, etc.).

Furthermore, other embodiments may include additional pre-processing or post-processing operations, whether on the edge device 204 or off-device. For instance, excess resources (e.g., unused programmable substrate, idle processor time, etc.) of the edge device 204 can be repurposed to implement a wide range of miscellaneous tasks, including for example, encryption, decryption, encoding, decoding, transcoding, transrating, format conversion, upsampling, downsampling, etc.

Processor—

In some embodiments of the invention, a processor 504 and associated storage 506 is provided. The processor can execute software which configures the programmable substrate 508 for full spectrum generation. In other embodiments, the programmable substrate is configured remotely for spectrum generation. In some circumstances, the programmable substrate may be configured at manufacture, and deployed in a “hardcoded” format. While dynamic and/or remote programming support is generally preferred for most implementations, it is appreciated that certain scenarios or constraints may render these features unsuitable or undesirable for use. For example, in closed-circuit operations, a pre-constructed rack unit or board may be swapped or placed into service, without the benefit of external network administration, or assistance. Such closed implementations may be particularly useful in sensitive security environments.

In one such variant, the processor 506 504 receives a pre-compiled binary image file for programming the programmable substrate 508. The pre-compiled binary image files may be compiled by a networked entity, based on known configurations and device layouts. Pre-compiled binary files are virtually impossible to tamper or reverse engineer; however, pre-compiled binary files are specific to the device; without safety precautions, an incorrect file can cause physical damage to device components. In contrast, other variants may provide metadata to the processor, enabling the processor to compile a binary image file suitable for device specific programmable substrate configuration. For example, such metadata may include total bandwidth, channel distribution, an allocation of services, etc. Metadata is significantly easier to distribute; however, compiling a binary image file is not trivial, and requires a much more capable processor, and associated software.

In one embodiment, the processor 506 programs a non-volatile memory (not shown) with a binary image file for programming the programmable substrate 508. Non-volatile memories, such as FLASH, EEPROM, EPROM, etc. retain their contents without power. Non-volatile binary image storage may be useful to accelerate start-up (e.g., after a power loss, or restart, etc.), or for other applications such as hot-swap embodiments. Programming or “burning” a binary image to non-volatile memory is much slower than directly programming the programmable substrate; however, once the image is burned into the substrate, the device can greatly speed up configuration. The non-volatile memory automatically configures the programmable substrate during power-up.

Alternatively, the processor 504 can program the programmable substrate 508 directly. For example, programmable substrates which are Look-Up-Table (LUT) based can be “written” to (similar to a Random Access Memory (RAM)). Similarly, Digital Signal Processor based substrates may be programmed by writing to its execution memory. Volatile memories, such as LUTs and RAMs, lose their contents when power cycled, and must be reprogrammed anew.

Alternative embodiments which are programmed remotely may similarly be “burned” or directly programmed. Existing solutions for remote configuration of programmable substrates are well known in the art, and not further described herein.

In another implementation of the present invention, a processor 504 and associated storage 506 configures the network interface 502 dynamically to selectively receive data from one or more external data content devices 208. The connections are dynamically determined based on e.g., one or more business and/or operational optimizations; for example, the processor may elect to maximize the number of profitable narrowcast services, at the expense of broadcast services. Other profit or revenue-maximizing algorithms are further discussed subsequently herein.

The processing subsystem 504 adds flexibility to the full spectrum generation apparatus 204, both in terms of content management, network operation, and other operational parameters. For example, in some embodiments, the processing subsystem 504 supports multiplexing of video or other content (e.g., programs) using feed-back or feed-forward information, as discussed in co-owned U.S. Pat. No. 7,602,820 issued Oct. 13, 2009 and entitled “APPARATUS AND METHODS FOR MULTI-STAGE MULTIPLEXING IN A NETWORK”, which is incorporated herein by reference in its entirety. Consider a cable network having a number of content sources 208, a spectrum generation device 204, and a service group containing a local hub. The edge device 204 negotiates with the local hub to reserve bandwidth for the local hub within the service group. The processing subsystem 504 may receive and grant requests for bandwidth for downstream use by the local hub. Thus, a portion of the frequency spectrum output is kept in “pristine” condition, thereby allowing the local hub to insert content (e.g., adding a QAM subsequently thereafter).

In another embodiment, the processing subsystem supports accessing data (such as video, audio or data files) over a network according to download or “on demand” paradigms, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 11/258,229 filed on Oct. 24, 2005 and entitled “METHOD AND APPARATUS FOR ON-DEMAND CONTENT TRANSMISSION AND CONTROL OVER NETWORKS”, which is incorporated herein by reference in its entirety. For example, a content distribution network (e.g., cable HFC) may be connected with a CSP (cellular service provider) or wireless service provider (WSP). On-demand content may be delivered via a “point-to-point” approach, where a session is established between a content receiving entity (such as a cellular telephone) and a distributing entity's processing subsystem (e.g., the full spectrum device 204). The processing subsystem 504 supports session establishment (e.g., a SIP session), and data flow control using protocols and bandwidth typically used for (i) providing on-demand services to subscribers within the cable network, and (ii) delivery and control of streaming multimedia to client mobile devices.

In yet other systems, the processing subsystem of the edge device 204 transparently and opportunistically utilizes bandwidth reclaimed after removal of null or “stuffing” data inserted into a program stream for, inter alia, producing constant-rate streams, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 11/291,328 filed on Nov. 30, 2005 and entitled “APPARATUS AND METHODS FOR UTILIZING VARIABLE RATE PROGRAM STREAMS IN A NETWORK”, which is incorporated herein by reference in its entirety. For example, in networks where bandwidth is largely variable and unpredictable, the processing subsystem 504 can actively detect “transient” bandwidth, and request additional content or backfill local content to deliver secondary content elements. Additionally, the secondary content elements occupy the same QAMs which also carry the primary or program content, thereby allowing for tandem use of existing QAMs.

Additionally, the processing subsystem 504 (where utilized) may utilize a “switched digital” approach to (i) deliver packetized content only when requested, and (ii) selectively switch cable modems (CMs) or other such CPE to and from certain downstream channels (e.g., DOCSIS QAM-modulated RF channels) based on switching algorithms, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 11/325,107 filed on Jan. 3, 2006 and entitled “METHODS AND APPARATUS FOR EFFICIENT IP MULTICASTING IN A CONTENT-BASED NETWORK”, which is incorporated herein by reference in its entirety. In one embodiment, the processing subsystem executes algorithms for detecting and exploiting the fraction of the available program channels which is not in use; hence, intelligent and timely switching of individual subscribers (or groups of subscribers) can reduce the number of downstream channels that must be allocated to delivery of content.

Moreover, other embodiments of the processing subsystem 504 can execute management and control of electronic devices connected to a network, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 11/363,577 filed on Feb. 27, 2006 and entitled “METHODS AND APPARATUS FOR SELECTING DIGITAL CODING/DECODING TECHNOLOGY FOR PROGRAMMING AND DATA DELIVERY”, which is incorporated herein by reference in its entirety. For instance, the processing subsystem may control hardware and software functions/modules of different devices on the network to enable various capabilities and options, including conditional access capabilities, video coding or compression capabilities, encryption schema, and network interfaces. Thus a full spectrum device (e.g., edge device) could support tailored conditional access, coding, encryption, and/or network interfaces for delivery of content to each particular client device of its service group.

Yet other embodiments of the processing subsystem 504 of the edge device can maintain and analyze historical viewing or use information, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 12/012,019 filed on Jan. 30, 2008 and entitled “METHODS AND APPARATUS FOR PREDICTIVE DELIVERY OF CONTENT OVER A NETWORK”, which is incorporated herein by reference in its entirety. Historical viewing and use information collected by the processing subsystem can be used to predicatively request or cache content for “stuffing” bandwidth that is not currently being consumed via consumer requests with programming that is predictively selected.

Processing subsystems can also control network bandwidth utilization by delivering to users only the minimum number of programs required by service provider policies, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 11/881,034 filed on Jul. 24, 2007 and entitled “METHODS AND APPARATUS FOR FORMAT SELECTION FOR NETWORK OPTIMIZATION”, which is incorporated herein by reference in its entirety. The flexibility of the content delivery could conceivably cause significant congestion during drastic changes in programming consumption; for example, bottlenecking at the full spectrum generation device 204. So-called “primetime” viewing typically comprises the maximum number of individual programs being delivered, as well as the maximum diversity of programs; the primetime demand for programming typically differs dramatically from the demand during early morning viewing, and also from that of other relatively high consumption periods. Consequently, in periods of excessive bottlenecking, the processing subsystem may be required to enforce minimum service provider policies.

Another “network friendly” policy executable within the processing subsystem 504 includes tiered usage of: (i) a reclamation process; (ii) and overflow process; and (iii) a triage process, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 12/152,749 filed on May 15, 2008 and entitled “METHODS AND APPARATUS FOR BANDWIDTH RECOVERY IN A NETWORK” (which claims the benefit of U.S. Provisional Patent Application No. 60/930,450 of the same title, filed on May 15, 2007), which is incorporated herein by reference in its entirety. For example, the processing subsystem 504 can enforce graded or escalating impact based on the severity of the bandwidth deficit.

Still other variations of processing subsystems “intelligently” optimize content-based network operation based on, e.g., cost and/or revenue implications in the context of “on-demand” video services, as discussed in co-owned, and co-pending, U.S. patent application Ser. No. 12/072,637 filed on Feb. 26, 2008 and entitled “METHODS AND APPARATUS FOR BUSINESS-BASED NETWORK RESOURCE ALLOCATION”, which is incorporated herein by reference in its entirety. The processing subsystem can dynamically evaluate and reallocate network assets based on, inter alia, the revenue and “cost” implications associated with various resource allocation options. For example, the processing subsystem assesses the various implications of different possible resource allocations within the on-demand (OD) delivery paradigm (e.g., FOD, SVOD, HDVOD, etc.). The processing subsystem 504 in one embodiment allocates/reallocates program streams (such as according to one or more predetermined or dynamically variable criteria) in order to continually optimize the revenue/profit versus resource cost equation.

Furthermore, commingling of video and data services can be optimized within various aspects of the present invention. For example, the invention can be used to boost utilization of a single QAM's capacity. Consider a DOCSIS 3.0 stream supporting up to 38.8 Mbps of payload; in one embodiment of the present invention, the underutilized portion can be stuffed with additional data (e.g., 30 Mbps baseline “stuffed” to support an additional 8.8 Mbps). Techniques for “packing” unused bandwidth are well known in the related arts, and include those specified in DOCSIS 3.0, and/or equivalent solutions used within DSMCC data carousels. DSMCC supports a variety of communication models, including interactive transport control of audio and video streams in a bi-directional environment such as a cable television VOD system.

More generally, however, those of ordinary skill in the related arts will recognize that allocated spectrum can be sub-divided into “slices” and apportioned to any number of users. Control channels can be used for distributing relevant information to the users including, for example, addressing, permissions, etc.

Programmable Substrate—

In one aspect of the present invention, the programmable substrate 508 of the device of FIG. 5 receives data from the network interface, and generates the entire spectrum for distribution to one or more subscribers within the serviced group. In one embodiment, the programmable substrate receives a plurality of time-multiplexed content data streams as previously described, and converts the content to a plurality of frequency-multiplexed channels (e.g., QAMs).

Common examples of programmable substrates 508 include FPGAs (Field Programmable Gate Arrays), PLDs (Programmable Logic Devices), GALs (Generic Array Logic), etc. as well as hybrid reconfigurable DSPs (Digital Signal Processors), Fast DACs and other general purpose processing cores. In one exemplary embodiment, the programmable substrate 508 is configured to perform highly specialized and optimized operations (examples are described in greater detail hereinafter). In less complex systems, a processor executing a generic instruction set may be sufficient. Similarly, multiple parallelized operations may preferentially be performed within dedicated logic; in contrast, serialized or unpredictably discontinuous operations can be more efficiently handled in software. Thus, the complexity and configuration of the edge device is directly related to the nature of spectrum generation.

Furthermore, it is appreciated that rapid improvements in technology (e.g., parallel processing, compiler efficiency, fabrication geometries, etc.) and corresponding decreases in component cost may be a consideration for future design construction. For example, it may be more cost effective to use higher-cost reprogrammable substrates which can be frequently upgraded, as opposed to “one-shot” lower-cost components. In other examples, older and lower cost components and existing software may be cheaper to maintain than porting existing software to new platforms. Other implementations which trade cost for substrate capabilities are readily appreciated by those having ordinary skill in the related arts, given the contents of the present disclosure.

In the exemplary embodiment, the programmable substrate comprises one or more FPGAs. Architecturally, FPGAs are based on small memory Look-Up-Tables (LUTs), which emulate logic (e.g., AND, NAND, OR, NOR, XOR, XNOR, etc.).

Consider the exemplary Look-Up-Table (LUT) 600 of FIG. 6, which has been programmed to emulate a logical AND gate. In this example, the two (2) input LUTs comprises a memory device that can store four (4) values. During operation, the input operands 602 “address” the stored value; i.e., if the first operand is a logic one (1), and the second operand is a logic zero (0), then the value at address #10b is returned. For example, the logical AND operation can be emulated by programming the LUT with a zero (0) value in addresses #00b, #01b, and #10b, and a one (1) in address #11b. When both the first and second input operands are a logical one (1), the LUT outputs a logical one (1); in all other cases, the LUT outputs a logical zero (0).

Typical implementations of LUTs are physically capable of emulating much larger and more complex logical operations. Historically, FPGAs were composed of four (4) input LUTs; however, recent advances in FPGA technologies have supported larger LUT sizes (e.g., eight (8) inputs, etc.). Moreover, as will be appreciated by those of ordinary skill in the art, FPGA LUT construction provides programmability and flexibility at the cost of gate efficiency. Static, stable, standardized, etc. portions of the apparatus could be more efficiently built using traditional Application Specific Integrated Circuit (ASIC) construction. Thus, in some embodiments, heterogeneous solutions may combine programmable logic with fixed logic gates and/or processor cores.

Other forms of programmable substrate may readily be substituted by those having ordinary skill in the art, given the contents of this disclosure. For example, while FPGAs are LUT-based, other devices may program arrays of fixed gate logic to create circuits. Such other programmable substrates may include Complex Programmable Logic Devices (CPLDs), Programmable Logic Devices (PLDs), Programmable Array Logic (PAL), Generic Array Logic (GAL), etc.

In one exemplary embodiment of the present invention, the programmable substrate 508 is programmed to transform the content data into its spectral equivalent. For instance, the programmable substrate is configured to execute a Fourier-type transform from the time frequency domain to the frequency time domain.

The time and frequency domain are related to one another by the Fourier Transform, and Inverse Fourier Transform. Common implementations of Fourier-type Transforms include Discrete Fourier Transforms (DFT), Fast Fourier Transforms (FFT), Discrete Hartley Transforms (DHT), Discrete Cosine Transform (DCT), Discrete Sine Transform (DST), etc. As used herein, the term “transform” refers to, without limitation, any mathematical association (discrete or otherwise), useful for converting data from a first domain (such as time, frequency, etc.), to a second domain.

The Fourier Transform decomposes a signal into its frequency-domain components, whereas the Inverse Fourier Transform performs the inverse transform; i.e., generates a signal from its frequency-domain (spectral) components. One example of a particularly useful Fourier-type Transform is the Fast Fourier Transform (FFT) and the Inverse Fast Fourier Transform (IFFT). The FFT/IFFT transforms are well known within the art, and highly optimized hardware realizations of the FFT/IFFT transforms are used in many signal processing operations. Typical FFT/IFFT implementations exploit the similarity in the forward and reverse directions to reuse hardware. Additionally, many solutions are performed “in place” within memory; i.e., the transforms occur within a single memory buffer. FIG. 7 is a graphical depiction 700 of the relationship between the FFT, and the IFFT.

FIG. 8a is a graphical representation of frequency spectrum generation based on one exemplary IFFT 800 implemented in accordance with one embodiment of the present invention. A stream of time-multiplexed data 802 is separated into its constituent elements 804. Each of the elements is assigned to an appropriate frequency resource (e.g., QAM). This assignment may be for example based on a higher level mapping of content streams or programs to various frequency resources. Then, each element is encoded as spectral coefficients 806 which are input to an IFFT. For example, as shown in FIG. 8a, a first constituent element 804A is assigned to QAM2, and a second constituent element 804B is assigned to QAM1. The IFFT generates the resultant spectrum 808, which is a summation of the products of the spectral coefficients multiplied by their corresponding frequency resource. As shown, if properly performed, the content 804 should have a distinct frequency band. The frequency domain division multiplexed signal is passed to the downstream interface for transmission.

FIG. 8b is a graphical representation of frequency spectrum generation based on a second exemplary embodiment of the present invention 850. In this embodiment, the content 804 within the multiplexed input is demultiplexed into its individual constituent components as above, yet an OFDM (orthogonal frequency division multiplexing) operation (also an IFFT) is applied so as to multiplex the various components onto various frequency carriers at various times, thereby creating both time and frequency diversity at the output of the edge device 204. More specifically, the content is spread over multiple time and frequency resources, thereby minimizing the effects of burst interference, or frequency specific interference (e.g., fading).

Furthermore, in such variants, the content 804 within the multiplexed input further comprises multiple individual constituent components, as a time-multiplexed stream of multiple content elements. These multiplexed components are then multiplexed onto various frequency carriers by the IFFT, thereby creating both time and frequency diversity for the already time-diverse stream at the output of the edge device 204. In this embodiment, the receiver (not shown) includes a demultiplexer at the output of the FFT, so as to demultiplex the recovered original data stream into its constituent content elements 804 if desired. Alternatively, a PID (process ID) or similar mechanism can be used to pull packets from the multiplex without demultiplexing.

As appreciated in the digital audio and video broadcasting arts, the present invention can be further modified to support a wide range of statistical multiplexing methods to more efficiently provide audio or video services within a given fixed bandwidth. Consider a number of services or streams each of which has varying bitrates. In one embodiment, a statistical multiplexer intelligently allocates bandwidth to each service based on, inter alia, Quality of Service (QoS) requirements such that prioritized services can have more bandwidth, than lower priority services. In fact, unlike prior art networks which are configured and planned around relatively static channel usage, the present invention enables much more flexible and dynamic configuration of frequency resources, without maintenance or labor. For example, a full spectrum edge device can configure its programmable substrate to accommodate changing bandwidth requirements.

Downstream Interface—

In one aspect of the present invention, the downstream interface 510 receives the output of the programmable substrate 508, and transmits the signal to one or more subscribers. In one embodiment, the downlink interface has a Radio Frequency (RF) output. In alternative embodiments, the signal is modulated to a direct laser output. In yet other alternative embodiments, the signal may be modulated onto wiring or any other modes of physical transference.

RF Output—

RF-based embodiments are generally constructed from oscillators, modulators, and amplifiers. Wireless variants may additionally include one or more antennas. Generally, any method for transforming a digital signal to an analog waveform is sufficient. Laser embodiments are constructed from a gain medium which converts energy to light. Common implementations of lasers utilize reflective surfaces and other optical apparatus (lenses, mirrors, splitters, etc.) to further modify the emitted light.

Ideally, sufficiently large bandwidths are necessary to support all services (analog, digital broadcast, VOD, SDV, HSD (e.g., DOCSIS 1.0/3.0) and RF-Two-way, etc.). The aforementioned exemplary full spectrum edge device generates a RF spectrum spanning from baseband to 1 (one) GHz. In future implementations, spectrum generation can be expanded beyond the current capabilities to support advanced technologies. For example, MoCA (Multimedia Over Coax Alliance) type communications are supported at higher frequencies (above 1 GHz). In fact, it will be recognized that current frequencies may constrained by the physical media of the distribution plant (e.g., the attenuation characteristics of coaxial cable); future advances in materials, network topologies, and/or methods can ostensibly support much higher frequencies/rates.

The range is nominally sub-divided into 6 (six) MHz increments and quadrature-amplitude modulated (also referred to throughout as a “QAM”); other larger or smaller increments (e.g., 8 MHz) may be used as well. For example, as described in co-owned and co-pending U.S. patent application Ser. No. 11/013,671 filed Dec. 15, 2004 and entitled “METHOD AND APPARATUS FOR WIDEBAND DISTRIBUTION OF CONTENT” and incorporated by reference in its entirety herein, describes support for wideband QAMs having larger bandwidths (e.g., 8 (eight) MHz bandwidths, etc.). Moreover, an edge device could offer mixtures of bandwidths, e.g., 4 MHz, 6 MHz, 8 MHz, etc. Additionally, even though the aforementioned increments are 6 MHz wide, multiple increments can be bundled, to form larger slots in blocks of 2, 4, 8, 12, 16, etc. (i.e., 12 MHz, 24 MHz, 48 MHz, 72 MHz, 96 MHz, etc.).

It is appreciated that the spectrum described above may also include prohibited frequency bands or buffers (e.g., guard bands) so as to mitigate, inter alia, inter-carrier or other types of interference. As used herein the term “contiguous” refers both to cases where the individual frequency bands or carriers are actually contiguous to others (i.e., no guard band(s)), or are contiguous but for one or more intervening guard bands.

Still other limited capability variants could reproduce a smaller spectrum, containing only limited, or special engagement programming. For example, in low use rural areas or mobile applications (e.g., a cruise liner, train, plane, etc.), a reduced-capability edge device could provide only limited channel selection to a few tuners. Similarly, such devices could be used in areas having significantly less programming content. These reduced-capability variants could support spectrums having a corresponding bandwidths e.g., 300 MHz bandwidth, 600 MHz bandwidth, etc.

In yet other embodiments, the downstream interface may be wireless. For example, multiple WiMAX base stations may be established by the MSO or other content provider. One or more of the WiMAX stations are coordinated full spectrum generation devices. Received content and/or data are transmitted to the CPE (which may include simultaneous constructive interference systems).

It can also be appreciated that the methods of the present invention may be practiced using any configuration or combination of hardware, firmware, or software, and may be disposed within one or any number of different physical or logical entities. For example, the aforementioned programmable substrate functionality may take the form of one or more computer programs. Alternatively, such computer programs may have one or more components distributed across various hardware environments at the same or different locations, such as where a network process is distributed across multiple platforms.

As yet another example, portions of the functionality may be rendered as a dedicated or application specific IC having code running thereon. Myriad different configurations for practicing the invention will be recognized by those of ordinary skill in the art provided the present disclosure.

Laser Output—

In another embodiment, the output of the edge device(s) comprises an optical domain (e.g., coherent or Laser) signal. As previously mentioned, laser embodiments are constructed from a gain medium which converts energy to light. Each bit stream (e.g., logical channel) is represented using a wavelength of light, which can be turned off-and-on independently. Fiber optic lasers “tune” light by changing various characteristics of the gain medium. For example, some “tuned” lasers adjust the size of the resonating cavity where the light is amplified. Heating or cooling the resonating cavity alters the resonating cavities refractive index (resulting in shorter or longer wavelengths). Common implementations of distributed feedback (DFB) lasers use a cooling system to maintain a constant temperature in the resonating cavity.

In one embodiment, a wave-division multiplexing (WDM) approach is used, wherein the various program streams received at the edge device via e.g., the time-multiplexed transports are converted to an amplitude, which is modulated onto the wavelength channel (i.e., amplitude modulation (AM)). For example, in one embodiment, the TDM signal is converted with an IFFT to a FDM equivalent; each of the resultant spectral coefficients specifies the amplitude of corresponding wavelength of optical energy within for a laser transceiver. Unlike the prior art solutions which route the entire RF spectrum to a converter which converts the analog waveform to a laser equivalent; exemplary embodiments can directly transform the data streams (TDM) to combined optical outputs (e.g., CWDM) within the same full spectrum edge device.

Furthermore, as appreciated by those skilled in the relevant arts, many schemes could exist for the foregoing WDM combining. For example, in one embodiment, the output of the edge device is provided to multiple inexpensive lasers, each of which generates only a subset (e.g., one) of light wavelengths. In other embodiments, the outputs of multiple edge devices can be coupled to multiple tunable lasers which can be configured to generate a wide range of spectrum. The different laser outputs can be multiplexed together on one or more optical mediums. To support legacy configurations, non-WDM approaches can also be used, wherein each discrete channel of information is carried over its own fiber from source to sink. For example, a laser with optical modulator receives electrical domain signals, and converts them to the optical domain.

In one variant, each of the separate wavelengths of light (here in the C-band (1528 to 1603 nm), L-band (1570 to 1604 nm), or S-band (1450 to 1500 nm) is generated by a distributed feedback (DFB) laser, and optically combined with other wavelengths within an optical multiplexer for carriage down a single fiber to one or more nodes, wherein the signal is then distributed to CPEs via the prevailing distribution medium (e.g., coaxial cable, CAT-5, optical fiber, wireless, etc.). Individual wavelengths are demultiplexed at the node via an optical demultiplexer. In one such implementation, each edge device 204 comprises a plurality of DFBs and an optical combiner to physically combine the various (e.g., 2, 4, 8, 16, etc.) different wavelengths onto the single fiber. This fiber is then used to service a given service group within the network.

Alternatively, these components may be distributed further downstream in the architecture, such as where the outputs from multiple edge devices are optically combined.]

Supported Modulation Schemes—

In the exemplary embodiment of the full spectrum edge device, various types of modulation schemes are supported, in order to make each edge device 204 “full service” (i.e., support each of the varied heterogeneous services now offered within the typical target network).

One such modulation type is QPSK (quadrature phase shift keying); this well known modulation supports e.g., “ALOHA”-based access protocols (e.g., pure ALOHA, slotted ALOHA, etc.), and DAVIC, for use in broadcasting system information, or low data rate transfers. More discerning QAM (e.g., 64-QAM or 256-QAM) modulation is used e.g., to support digital encrypted broadcast functions including Encrypted MPTS and SPTS multicast and unicast, Switched Digital Video (encrypted SPTS multicast), and VOD (encrypted SPTS unicast).

For example, DOCSIS services (e.g., DOCSIS 1.0, 3.0, etc.) utilize 64-level or 256-level QAM (64-QAM or 256-QAM) for modulation of downstream data, and QPSK or 16-level QAM (16-QAM) is used for upstream modulation. DOCSIS 2.0 and 3.0 also require that 32-QAM, 64-QAM and 128-QAM be available for upstream data.

Accordingly, the exemplary configuration of the edge device programmable substrate includes multiple modulation logic in order to support these various modulation types.

Methods—

Referring now to FIG. 9, one embodiment of the generalized process for spectrum generation in accordance with the present invention is described. In one aspect, the spectrum generation entity 500 manages service delivery between a number of sources and sinks (e.g., adding, removing, and/or modifying distribution paths). In one exemplary embodiment, a single spectrum generation entity generates a full spectrum signal encapsulating broadcast and narrowcast services. It is appreciated that in alternative variants, spectrum generation may be performed by a number of devices or subsystems (e.g., multiple rack units at a hubsite, etc.).

At step 902, the spectrum generation entity requests one or more services or content from a plurality of content sources 208. Typical cable networks comprise a number of content sources including e.g., Standard Definition (SD) content, High Definition (HD) content, Video-on-Demand (VOD) content, Switched Digital Video content, and High Speed Data (e.g., DOCSIS). However, content sources broadly include any source of digital data such as for example a third party data source, mass storage devices (e.g., RAID system), file servers, etc.

In one embodiment of the present invention, the requests for one or more services are based on one or more requests received from a plurality of served Consumer Premises Equipment (CPE) 202. The CPE includes any equipment in the “customers' premises” (or other locations, whether local or remote to the distribution server) that can receive the outputs generated by the spectrum generation device. In alternative embodiments, the requests for one or more services are based on one or more directives received from an external network management entity.

In yet other embodiments, the requests for one or more services may be responsively sent, based on conditions detected at another spectrum generation entity. For example, additional spectrum generation entities may be used to supplement service offerings, or prevent noticeable service blackout during device failure.

At step 904, the spectrum generation entity receives content for delivery. Content may be scheduled for reception in segments, downloaded into a queue, etc. In one variant the subscriber content is composed of both broadcast and narrowcast elements. Examples of such data sources includes e.g., Standard Definition (SD) content, High Definition (HD) content, Video-on-Demand (VOD) content, Switched Digital Video content, and High Speed Data Over Cable Services Interface Specification (HSD DOCSIS), etc.

It is also appreciated that the spectrum or edge device may be “flooded” with all available programming (at least in the linear domain), akin to a prior art switched digital broadcast model. In the prior art model, the lack of any demand with the serviced subscriber group for a given program allows that program to be “switched out” from delivery, thereby freeing bandwidth for other programs or services which are being actively utilized. When a “first” request for the switched-out content is received, the switch responsively switches that program stream back into the delivered set.

Similarly, one embodiment of the present invention floods the edge device with all relevant program streams, and the processor 504 and/or substrate 508 are configured to selectively include or remove these streams based on serviced user requests for the content. In one such variant, a given program stream within the time-multiplexed stream is simply allocated to a buffer or other mechanism which is not included in the IFFT operation. Likewise, another stream can readily be mapped onto a frequency resource in place of the removed stream.

In one exemplary embodiment, the content is received via a Time Domain Division Multiplexed (TDM) network. Alternate embodiments may receive the plurality of content via other multiplexing schemes (e.g., FDM, etc.). Furthermore, system design considerations may require the flexibility of packet-switched delivery, or alternately, the bandwidth guarantees of circuit-switched delivery. Additionally, network content delivery may further include capabilities and support for Quality-of-Service (QoS) parameters. QoS parameters support resource reservation control mechanisms and may, inter alia, provide different priorities to different content data, or guarantee a minimum delivery rate. Consistent spectrum generation may require guarantees for consistent bit rates, delays, jitter, packet loss, bit error rates, etc. Real-time streaming multimedia applications often require fixed data rates, and are delay sensitive.

In one aspect of the present invention, the content data can be flexibly sourced from a wide variety of devices. In one embodiment, the content data is generically formatted in accordance with one or more broadcast services, and/or one or more narrowcast services. Alternatively, the content data may be specific to a particular service, and provided via specialized or proprietary formats. In certain embodiments, narrowcast data content can include user-centric and/or user-specified content (various examples for narrowcast user content are described in greater detail herein, see discussion of On Demand Services) as well as targeted secondary content.

In one variant, the content data is dynamically included based on one or more business optimizations (e.g., maximize narrowcast service, maximize subscriber coverage, etc.). In other variants, the content data may be dynamically included based on one or more network considerations (e.g., robust service coverage, service recovery, etc.). In yet other variants, the content data may be selected based on one or more apparatus considerations (e.g., device limitations, subscriber CPE limitations, etc.). Such considerations may also be remotely handled via a centralized network management entity.

The plurality of data content may be received from one or more encryption devices, or “in the clear” (unencrypted) from one or more source content devices. Still other variants may support encryption for a portion of the received streams (e.g., to support mixtures of externally encrypted and unencrypted sources, etc.).

At step 906, the spectrum generation device transforms the plurality of content to a full spectrum format. The received data content is organized, assigned, or collated into a number of channels for transfer. In one embodiment, one stream of data content (which may include one or more program streams) is assigned to a channel suitable for generating 6 (six) MHz of bandwidth. Such organization may include filling a suitably sized buffer memory for spectrum conversion. In some variants, larger channels can be created by aggregating 2, 4, 8, 12, 16, etc. buffer memories (content streams) together.

In yet other variants, variably sized channels may be created by providing a variably sized memory buffer, which can be dynamically changed. Still other variants may provide “padding” to support spectrum generation without content (such as may be useful when rolling out new features, or removing old features, etc.).

Additionally, in some implementations, the channel data is collated first (e.g., as stored within memories), and then assigned to a spectrum resource. Multiple stage processes can add additional data delivery flexibility, at increased complexity. For example, in one embodiment, the channels may be further organized based on one or more optimization processes (e.g., so as to avoid bandwidth constraints, or achieve other operational goals). In other embodiments, the channels may be organized based on a coherent standard or policy deployed on a network-wide basis.

Similarly, in yet other embodiments, the channels may be further organized flexibly within a certain range. For example, various portions of the spectrum may be allocated for legacy devices (e.g., analog and digital standard definition service), whereas other portions of the spectrum may be restricted for specific users (e.g., to support various narrowcast options).

At step 908, the spectrum generation device transmits the transformed (frequency time domain) content for reception by the plurality of sinks, such as subscriber CPE 106. In one exemplary Radio Frequency (RF) embodiment, transmission of the frequency channels includes conversion from digital samples to an analog baseband waveform, and frequency mixing for transmission. In alternate embodiments, direct laser transmission of the channels includes conversion from digital samples to an optical waveform for transmission via a fiber optic cable.

Referring now to FIG. 9a, one exemplary implementation of the generalized method of FIG. 9 is illustrated.

As shown, the method 950 comprises the edge device 204 first receiving a time-domain division multiplexed stream of content from its Gig-E interface (step 952). For instance, the stream may comprise several multiplexed program streams collectively forming a packet stream encapsulated in an appropriate protocol. Since a packet-switched delivery network is utilized, it is feasible that some packets may arrive out-of-order, and hence may be buffered and reordered upon receipt.

Next, per step 954, the received stream is demultiplexed, such as by packet identifiers 30 that associate each packet with a particular stream. The individual streams demultiplexed from the parent stream are then individually buffered (step 956), and allocated to particular frequency domain resources per step 958. For example, as shown in FIGS. 8a and 8b, various program streams may be mapped to one or more RF output channels (e.g., QAMs), including: (i) one program stream per QAM; (ii) multiple streams per QAM; and (iii) multiple QAMs per stream (e.g., using the aforementioned wideband tuner).

Next, per step 960, the edge device transforms the individual program streams into a full-spectrum representation of the input data. For example, in one embodiment, the input bitstream for each individual program stream is allocated to an individual frequency band or subcarrier using an IFFT. Alternatively, a bitstream may be allocated across multiple different carriers (akin to OFDM), thereby providing both time and frequency diversity if desired.

Lastly, per step 962, the data output from the IFFT operation is converted to the analog domain (e.g., using a D/A converter), upconverted as required, and transmitted over the frequency spectrum effectively as a wideband RF signal.

Example Operation—

The following scenarios illustrate the operational and other benefits of one or more aspects of the present invention. Specifically, similar functions implemented within an extant cable distribution system using prior art solutions required extensive capital expenditure, and extensive maintenance. In contrast, the present invention quickly and efficiently provides deployments of improved functionality in a substantially seamless fashion.

Analog Reclamation—

As previously described, the cable spectrum may be composed of analog channels, digital channels, High Definition (HD) channels, video-on-demand (VOD) channels, switched digital video (SDV) and high speed data (HSD). Efforts to replace less efficient analog channel usage with digital counterparts are currently under both federal and commercial consideration. Prior art networks are both difficult to maintain, and upgrade; the restructuring of channel structure is an expensive and onerous task requiring significant amounts of capital outlay, and rewiring.

FIG. 10 illustrates one possible allocation 1000 of radio resources allocated to various services provided by a cable network provider. The cable spectrum is composed of QAMs which are allocated to analog channels 302, digital channels 304, High Definition (HD) channels 306, video-on-demand (VOD) channels 308, switched digital video (SDV) 310 and high speed data (HSD) 312, etc. The relative proportion of these various content types are based on business considerations; as previously mentioned. Narrowcast services such as HD, VOD, and SDV services are considerably more profitable; however, customers demand both breadth and legacy compatibility offered by analog and digital channels.

FIG. 10 illustrates a second spectrum allocation 1050, which is representative of current and future planned efforts to replace less efficient analog channel usage with digital counterparts, while expanding more profitable narrowcast offerings.

The previously described spectrum generation entity can accommodate analog reclamation (or any spectrum allocation changes) by reprogramming the network interface to receive data from new content sources, and a reconfiguration of the output frequency channel locations. Instead of receiving the current allocation of analog services, the spectrum device can be programmed to receive content data from another networked content source. Similarly, channel structure can be changed to back-fill the reclaimed spectrum. New digital content can be addressed with new parameters for connecting to content servers, and channel assignments. Thus, various embodiments of the present invention can advantageously configure networks (in compliance with federal analog reclamation efforts) remotely, entirely in firmware or software, and virtually instantly.

On Demand Services—

The present invention provides previously unattainable degrees of freedom for allocating between broadcast and narrowcast capabilities. This includes instantiation of user-specific narrowcast or unicast channels for delivery of on-demand content. For example, “entitlement” based content data control is provided to a CPE via an on-demand session, if the CPE or subscriber is entitled to the content. In one embodiment, this is accomplished via the methods and apparatus disclosed in co-owned, co-pending U.S. patent application Ser. No. 12/536,724 filed on Aug. 6, 2009 and entitled “SYSTEM AND METHOD FOR MANAGING ENTITLEMENTS TO DATA OVER A NETWORK”, incorporated herein by reference in its entirety. As discussed therein, in one embodiment, a request for content is received from the CPE at an entity (e.g., headend server) of the content and data distribution network. The network entity obtains information identifying the user account (such as subscriber identification number, account number, etc.), and uses this information to request entitlements from an entitlements server (also located at the headend in one embodiment). Based on the results returned from the entitlements server, the network entity either grants or denies the request. The entitlements server accesses subscription information in a subscriber database to obtain sufficient information to determine the entitlements of the subscriber. When the requesting user is determined to be entitled, the content (e.g., movie) can be provided to the spectrum generation device 204 for transmission via a limited engagement channel that is instantiated for that user only. The present invention can thus temporarily create a limited engagement channel specific to the entitled CPE or subscriber only. At the conclusion of the delivery, the resources are no longer used, and may be readily reabsorbed into the spectrum budget.

Switched Digital Video (SDV)—

As another example, the edge device 204 of the invention can be disposed at a hubsite within a network, and operate according to an SDV paradigm. As previously described, traditional SDV floods the hubsite switch with all of the available programming; delivery of each program stream downstream however is predicated upon one or more users watching a given stream. When no users within the serviced group are watching a given program, that program is switched out from downstream delivery, and the bandwidth that was being used to deliver it reclaimed.

Similarly, in the context of the present invention, the edge device 204 may act as a switch, being controlled either remotely or by a local process which determines whether any subscribers have selected a given program stream, and if not, remove this stream from delivery, such as by (i) simply not demultiplexing it from the incoming multiplexed content stream; (ii) demultiplexing it but discarding the packets; or (iii) causing an upstream entity to remove it from the received multiplexed stream. Advantageously, however, the edge device 204 can also reallocate reclaimed spectrum for use in the same or other services (e.g., for a VOD session).

Passive Optical Networking (PON)—

In yet another example, the edge device 204 of the present invention can support yet other physical mediums and protocols. For example, in one embodiment, the output of the full spectrum generation device may couple directly to a Passive Optical Network (PON) architecture (e.g., Ethernet over PON, or EPON). A typical PON is a point-to-multipoint, fiber-to-premises network architecture where unpowered optical splitters are multiplexed over a single optical fiber to serve multiple premises. For example, a full spectrum device that acting as an optical line terminal (OLT) can transmit data to a number of optical network unit (ONU) CPEs. Yet other fiber optic distribution schemes may be readily implemented by ones of ordinary skill in the related arts given the present disclosure.

Business Models and “Rules” Engine—

In another aspect of the invention, one or more computer programs running on the processor 506 of the fall spectrum apparatus 204 includes a so-called “rules” engine. This engine comprises, in an exemplary embodiment, one or more software routines adapted to control the operation of the apparatus in order to achieve one or more goals relating to operations or business (e.g., profit). Included within these areas are network optimization and reliability goals, increased maintenance intervals, increased subscriber or user satisfaction, increased subscription base, higher revenue or profit (e.g., from increased advertising revenues), more subscriber “views” of given content, higher data download speed, increased bandwidth and responsiveness to changing demands for bandwidth, reduction of undue channel replication, and so forth.

These rules engine may comprise a separate entity or process, and may also be fully integrated within other processing entities, and controlled via e.g., a GUI displayed at a central network management facility, coupled via the network interface 502. In effect, the rules engine comprises a supervisory entity which monitors and selectively controls the operation of the spectrum generation device(s) at a higher level, so as to implement desired operational or business rules.

For example, the central network entity may invoke certain operational protocols or decision processes based on, inter alia, information or requests received from the service group, conditions existing within the network, demographic data, geographic data, user preferences, etc. However, these processes may not always be compatible with higher-level business or operational goals, such as maximizing profit or system reliability. Hence, when imposed, the business/operational rules can be used to dynamically (or manually) control the operation of the full spectrum apparatus 204. The rules may be, e.g., operational or business-oriented in nature, and may also be applied selectively in terms of time of day, duration, specific local areas, or even at the individual user level.

For example, when sufficient bandwidth is present, the apparatus may deliver narrowcast programming to optimize programming revenues. However, during instances of increased demand on the network, narrowcast programming may be greatly limited. In other words, as bandwidth demand increases, lower-revenue narrowcast programming may be pruned out. Similarly, the central network authority can balance between targeted narrowcasting, and service coverage. Highly targeted narrowcast services are generally tailored to small coverage areas; thus as a service group diminishes in size, the proportion of targeted narrowcast services can increase (and vice versa). Dynamic adjustment of narrowcast relevancy can greatly improve network profitability. These features are readily leveraged within the edge device 204 of the invention due to its ability to be almost instantaneously remotely reprogrammed to adjust is spectral output

Additionally, the benefits of remote monitoring, configuration and provisioning capability enable greater flexibility in, inter alia, (i) troubleshooting and repairing faults within the content delivery network; and (ii) changing or reconfiguring content delivery within the content delivery network. The reduced maintenance and upgrade costs have tangible value, as realized in both saved labor costs, and reduced infrastructure investments.

Many other approaches and combinations of various operational and business paradigms are envisaged consistent with the invention, as will be recognized by those of ordinary skill when provided this disclosure.

It will be recognized that while certain aspects of the invention are described in terms of a specific sequence of steps of a method, these descriptions are only illustrative of the broader methods of the invention, and may be modified as required by the particular application. Certain steps may be rendered unnecessary or optional under certain circumstances. Additionally, certain steps or functionality may be added to the disclosed embodiments, or the order of performance of two or more steps permuted. All such variations are considered to be encompassed within the invention disclosed and claimed herein.

While the above detailed description has shown, described, and pointed out novel features of the invention as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the invention. The foregoing description is of the best mode presently contemplated of carrying out the invention. This description is in no way meant to be limiting, but rather should be taken as illustrative of the general principles of the invention. The scope of the invention should be determined with reference to the claims.

Claims

1. A method of providing a plurality of content elements to a plurality of users of a content distribution network, said method comprising:

receiving a plurality of digital content elements which are accessed from a plurality of digital content sources having different content types, said plurality of digital content elements received as part of a multi-program transport stream (MPTS) at a transformation device;

including or removing one or more of said plurality of digital content elements from said plurality of digital content elements based on serviced user requests for said plurality of digital content elements;

transforming, at said transformation device, said received plurality of digital content elements to one or more frequency time domain signals using digital domain processing;

assigning one or more radio frequency carriers to channel allocations for respective ones of said transformed signals; and

transmitting said transformed signals to said plurality of users over said assigned one or more radio frequency carriers;

wherein said act of transforming comprises performing digital domain processing that aggregates respective ones of said transformed signals together according to at least one of said content types by dynamically reprogramming said channel allocations.

2. The method of claim 1, wherein said transformation device comprises a demultiplexer function configured to demultiplex said MPTS to recover individual program streams associated with said plurality of digital content elements.

3. The method of claim 1, wherein said one or more frequency carriers comprise quadrature amplitude modulation (QAM)-modulated channels each having a frequency bandwidth of approximately 6 MHz.

4. The method of claim 1, wherein said digital domain processing comprises an inverse Fast Fourier Transform (IFFT).

5. The method of claim 1, wherein said plurality of users are associated with a common service group within said network.

6. The method of claim 1, wherein said transformation device is substantially remotely reprogrammable, and said method further comprises dynamically changing an allocation of said transformed digital content elements to said one or more frequency carriers remotely.

7. The method of claim 1, further comprising dynamically inserting secondary content elements into said plurality of digital content elements before said transforming.

8. A network apparatus configured to deliver content from a plurality of content sources to a plurality of users associated with a content distribution network, said network apparatus comprising:

at least one first interface configured to access at least one of a plurality of digital content sources in communication with said content distribution network;

a storage apparatus configured to at least temporarily store a plurality of accessed digital content elements from said plurality of digital content sources;

a transformation device configured to:

receive said accessed at least one of said plurality of digital content elements as part of a multi-program transport stream (MPTS);

include or remove one or more of said at least one of said plurality of digital content elements from said plurality of digital content elements based on serviced user requests for said plurality of digital content elements; and

transform said plurality of digital content elements from one or more time frequency domain signals to one or more frequency time domain signals via digital domain processing; and

dynamically reprogram one or more channel allocations so as to aggregate respective ones of said transformed signals together by a content type; and

at least one second interface configured to transmit said transformed one or more frequency time domain signals to said plurality of users over respective ones of a plurality of radio frequency carriers.

9. The apparatus of claim 8, wherein said plurality of radio frequency carriers comprise quadrature amplitude modulation (QAM)-modulated channels.

10. The apparatus of claim 8, wherein said digital domain processing comprises an inverse Fast Fourier Transform (IFFT) apparatus.

11. The apparatus of claim 8, wherein said at least one first interface comprises a gigabit Ethernet network, and said at least one second interface comprises a substantially circuit switched frequency distribution network.

12. The apparatus of claim 8, wherein said transformation device is disposed at a hubsite of a content distribution network and away from a core of said content distribution network.

13. The apparatus of claim 8, further comprising a radio frequency (RF) combiner adapted to combine said one or more frequency time domain signals output from said transformation device with that of another transformation device in said network.

14. The apparatus of claim 8, wherein said transformation device is remotely programmable.