Provided is a method and system for a radio system including at least one base station and terminal equipment including a receiver and a transmitter. The transmitter is structured and arranged to independently adjust a symbol rate of at least two signals and combine the two signals after adjusting the symbol rate. The transmitter then transmits the combined signal along one physical path. By adjusting the signal rate before combining the two signals, the transmitter optimizes the signal qualities of each of the signals.
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1. A data transmission method used in a radio system including at least one base station and terminal equipment, the terminal equipment including at least a transmitter and a receiver, the transmitter and the receiver being adapted to communicate with each other over at least one physical channel, the method comprising:
receiving in the a transmitter, at least two signals, each having a unique differing signal quality requirements; independently adjusting a symbol rate of the at least two received signals if a signal quality requirement of one of the at least two received signals is different from a the signal quality requirement of the other of the at least two received signals by a predetermined amount, the adjusting compensating for the difference; combining the at least two received signals to produce a combined signal; and transmitting the combined signal along the at least one physical path configured to carry communication between the transmitter and a receiver, wherein independently adjusting a symbol rate is performed prior to combining the at least two received signals.
10. A radio system including at least one base station and terminal equipment, the terminal equipment at least one of which including a receiver and or a transmitter, the receiver and the transmitter being configured to communicate with each other over at least one physical channel, wherein the transmitter is structured and arranged to transmit at least two received signals over one physical path, each the received signal signals having a unique differing signal quality requirements, the transmitter comprising at least:
a symbol rate adjuster configured to independently adjust a symbol rate of each of the at least two received signals if a signal quality requirement of one of the at least two received signals is different from a signal quality requirement of the other of the at least two received signals by a predetermined amount; and a combiner configured to combine the at least two received signals to produce a combined signal for transmission along the at least one physical path; wherein the symbol rate adjuster adjusts, if necessary, the symbol rate of at least one of the at least two received signals before the combiner combines the at least two received signals.
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This application is the national phase of international application PCT/FI99/00248 filed Mar. 25, 1999 which designated the U.S.
The invention relates to a data transmission method, which is used in a radio system comprising at least one base station and terminal equipment comprising a receiver and a transmitter and communicating with each other over at least one physical channel.
The invention further relates to a radio system, particularly a radio system comprising at least one base station and terminal equipment comprising a receiver and a transmitter and communicating with each other over at least one physical channel.
Present mobile telephone systems attempt to provide the user with increasingly versatile services. This goal is shared by IMT-2000 (International Mobile Telecommunications for the Year 2000) services which aim to offer high-quality speech/audio signal transmission, high-rate data transfer, photograph transmission and video image transmission. In addition, the IMT-2000 service encompasses interactivity, multimedia electric mail, video conferences and target location determination, for example.
Transferring different data requires different symbol rate and signal transmission power. In the present radio systems the symbol rate is not optimized for the changing channel conditions since the symbol rate of several signals cannot be adapted in one physical channel. If, for example, two service signals transmitted over the same physical channel have differing quality requirements when received and the signals act differently when the delay profile of the channel changes, problems affecting the power level of the two signals occur. Such a problem typically arises when Reed-Solomon coding and convolution coding are used together. When the channel delay profile changes, a situation may arise when the first signal in accordance with the example is barely acceptable in terms of quality, while the other signal is of unnecessarily high quality. The simulation is particularly critical when a service signal only requiring a low symbol rate forces a service signal requiring a high symbol rate to use extra transmission power. The prior art solutions fail to resolve this disparity. Unresolved, the disparity will cause interference over the whole area of the radio system.
An object of the invention is thus to provide a method and a radio system implementing the method so as to solve the above problems and balance the signal quality. This is achieved by a method of the type described in the introduction, the method being characterized by the transmitter transmitting at least over one physical channel at least two signals having differing quality requirements when received, and the transmitter changing, if necessary, signal-specifically the symbol rates of the signals used over the physical channel in order to meet the quality requirements.
The radio system of the invention is characterized by the transmitter being arranged a transmit over one physical channel at least two signals having differing quality requirements when received, the transmitter therefore comprising at least means for changing the symbol rate of the signals signal-specifically in order to meet the quality requirements, and combination means for combining the signals in the same physical channel.
A plurality of advantage can be achieved with the method and system of the invention. The desired quality requirements of a signal to be received can be balanced, which enables optimized transmission power be used. The result is less interference in the radio system.
The invention is now described in closer detail in connection with the preferred embodiments with reference to the accompanying drawings, in which
The solution of the invention is suited particularly for WCDMA (Wideband Code Division Multiple Access), UMTS (Universal Mobile Telephone System) and IMT-2000 radio systems. Hence, the invention is suitable for at least TDMA-based (Time Division Multiple Access) and CDMA-based radio systems.
Examine first by means of
Examine now a solution of the invention by means of
In a preferred embodiment of the invention the symbol rate of the transmitter 190 can be controlled by a receiver. In such a case, a control signal (CONTROL SIGNAL FROM RECEIVER) is supplied from the receiver to a control unit 224 of the transmitter, the control unit controlling the blocks 202, 208 changing the symbol rate as instructed by the control signal. The control block 224 can also control the block 214 changing the symbol rate if such a block is in use at the transmitter 190. The signals 1 to P are also supplied to the control block 224, whereby the control block 224 knows the required symbol rate. Removal coding and/or repetition coding changing the symbol rate and the transmission power is performed both for the transmitter and the receiver in a known manner. Consequently, the change does not otherwise affect the data transmission.
In the solution of the invention, a receiver 280 operates in the following manner. The antenna 334 receives the signal, which is a combination signal consisting of several signals. The received signal propagates via the duplex-filter 332 to a filter 336, which only allows the desired band to pass. The filtered signal is demodulated by multiplying the signal at a multiplier 340 by the signal of a local oscillator 342, and low-pass-filtering the signal at a filter 344. Next, the aim is to keep the power level of the received signal unchanged with an ACC amplifier 346. The signal is changed to digital by an analogue/digital converter 348. Since the signal is a multipath-propagated signal, the situ is to combine the signal components propagated via different paths in a block 350 which, in accordance with the prior art, comprises a plurality of RAKE branches. The signal components received by the RAKE branches at different delays are searched by correlating the received signal with the spreading codes used, which are delayed by predetermined delays. When the signal component delays are found out, signal components belonging to the same signal are combined. Simultaneously, the spreading coding of the signal components is decoded. Next, the control signals and data signals included in the received signal are separated by demultiplexing at means 352. The signal part containing data is conveyed to be deinterleaved at means 354. Here, the interleaving of the block corresponding to the interleaving means 316 is thus deinterleaved. Next, at means 356, the signal undergoes an inverse operation of the symbol rate change corresponding to the transmitter block 314. Hence, if the transmitter block 314 has performed removal coding, the block 356 performs repetition coding of a corresponding extent. Next, the combination signal is divided into P signals at demultiplexing means 358. The interleaving of the first signal is deinterleaved at deinterleaving means 360, the symbol rate is inversely adapted in relation to the adaptation of the transmitter block 302 at means 362 and the signal coding is decoded at the means 362, in which case the signal 1 is available to the receiver. A similar procedure is repeated in connection with other demultiplexed signals; similarly, the interleaving of the signal P is deinterleaved at means 366, removal coding or repetition coding is performed at means 368, and the signal is decoded at means 370. The means 300, 306 of the transmitter usually perform convolution coding, the convolution coding being decoded by the means 364, 370 of the receiver.
The receiver 280 further comprises a block 372 measuring the signal quality. If any of the received signals does not meet the quality requirements or exceeds the quality requirements too dramatically, in other words deviates too much from a predetermined quality requirement, a signal controlling the symbol rate is supplied from the block 372 to the block 318 of the transmitter part for the control channel.
The solution of the invention is also suited for radio systems wherein the physical channel is based on bursts instead of spreading code(s), as is the case with the TDMA-based transmissions for example in a GSM radio system. In such a case, a plurality of service signals can be transmitted at an optimal power level in the same burst. The advantage of this is that the receiver does not need to receive separate signals from each service. This also applies to the TDMA/CDMA radio system wherein spreading coding is used within the burst. Hence, several different services can be simultaneously placed for the code or group of codes to be used in the burst.
Although the invention is described above with reference to the example in accordance with the accompanying drawings, it is obvious that the invention is not restricted thereto but can be modified in various ways within the scope of the inventive idea disclosed in the attached claims.
Rikkinen, Kari, Pehkonen, Kari, Toskala, Antti, Holma, Harri
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