Apparatus and method for transmitting and receiving packets in a mobile communication system supporting hybrid automatic repeat request

Abstract

An apparatus and a method are provided for operating harq in a mobile communication system. The method includes receiving a number of harq processes of a semi-persistent resource allocation and semi-persistent resource allocation interval information for a first transmission; receiving data in the first transmission at a subframe based on the semi-persistent resource allocation interval information; calculating a harq process IDentifier (id) using the number of harq processes of the semi-persistent resource allocation, the semi-persistent resource allocation interval information, and time information; receiving control information including the harq process id on an L1 control channel; receiving data in a retransmission based on the control information including the harq process id; combining the data received in the first transmission and the data received in the retransmission; and decoding the combined data.

Description

For example, time information of semi-persistent resource 415 is (434, 6), and time information of semi-persistent resource 420 is (436, 6). Calculating a semi-persistent resource-dedicated HARQ process identifier from the time information of the semi-persistent resources at a particular time is possible by defining a function having, as its inputs, a semi-persistent resource allocation interval 430 and the number of HARQ processes allocated for (or associated with) semi-persistent resources. Therefore, a semi-persistent resource-dedicated HARQ process identifier can be expressed as shown in Equation (2).
semi-persistent resource-dedicated HARQ process identifier=F1(i,n,t)  (2)

In Equation (2), i denotes a semi-persistent resource allocation interval expressed in units of 10 msec, n denotes the number of semi-persistent resource-dedicated HARQ processes, and t denotes time information of the timing at which semi-persistent resources are allocated.

For example, regarding calculation of an index of the semi-persistent resource-dedicated HARQ process, an index of a HARQ process can be calculated from time information using the method of Equation (3), and an actual identifier of the HARQ process can be determined from the index.
semi-persistent resource-dedicated HARQ process's index=MOD[s,n],s=ceiling[t/i,1]  (3)

In Equation (3), i denotes a semi-persistent resource allocation interval expressed in units of 10 msec, n denotes the number of semi-persistent resource-dedicated HARQ processes, and t denotes time information of the timing at which semi-persistent resources are allocated.

The HARQ process index, converted into an integer of the semi-persistent resource-dedicated HARQ process, is information related to a relative sequence of the particular HARQ process in a set of semi-persistent resource-dedicated HARQ processes. For example, if x₀, x₁, x₂, . . . , x_n are assigned to an arbitrary UE as semi-persistent resource-dedicated HARQ process identifiers, a process index 0 indicates an HARQ process x₀, an index 1 indicates an HARQ process x₁, an index 2 indicates an HARQ process x₂, and an index n indicates an HARQ process x_n. A relation between the semi-persistent resource-dedicated HARQ process identifiers and the HARQ process indexes can be notified to the UE through a call setup process.

It is assumed in Equation (3) that one semi-persistent resource is allocated in one interval. That is, Equation (3) is applied when semi-persistent resources are allocated only for HARQ initial transmission. If several semi-persistent resources are allocated in one interval, for example, if semi-persistent resources are allocated so that they can be used for first n HARQ transmissions, t, in Equation (3), denotes time information for the time at which semi-persistent resources used for initial transmission are allocated. If Equation (3) is applied on the assumption that a semi-persistent resource allocation interval is 20 msec and the number of semi-persistent resource-dedicated HARQ processes is 3, a HARQ process index for the first semi-persistent resource 415 is 1, and its associated HARQ process identifier is x₁. Further, a HARQ process index for the second semi-persistent resource 420 is 2, and its associated HARQ process identifier is x₂. Finally, a HARQ process index for the semi-persistent resource 425 is 0, and its associated HARQ process identifier is x₀.

Therefore, if the UE initially receives a HARQ packet through semi-persistent resources, it calculates a HARQ process identifier associated with the HARQ packet using time information for the initial reception timing, and then identifies HARQ retransmission for the HARQ packet using the HARQ process identifier.

FIG. 5 is a flowchart illustrating an operation of HARQ-receiving data in a UE according to the second embodiment of the present invention.

Referring to FIG. 5, in step 505, the UE performs call setup. During the call setup, the UE receives information on semi-persistent resource-dedicated HARQ processes identifiers and soft-buffer size. When the number of HARQ processes allocated for semi-persistent resources is defined as n, the UE assigns n soft buffers corresponding to the buffer size for semi-persistent resources. In addition, the UE receives a signaling including mapping information between the semi-persistent resource-dedicated HARQ process identifier indexes and the HARQ process identifiers in the call setup process. In short, when n processes x₀, x₁, x₂, . . . , x_n-1 are allocated for semi-persistent resources, the UE perceives the relation between the HARQ process identifier indexes and the actual HARQ process identifiers based on the mapping information. For example, when HARQ process 1, HARQ process 3, and HARQ process 7 are allocated for semi-persistent resources, the mapping information between the semi-persistent resource-dedicated HARQ process identifier indexes and the HARQ process identifiers can be expressed as shown in Equation (4).
HARQ process 1=HARQ process identifier index 0
HARQ process 3=HARQ process identifier index 1
HARQ process 7=HARQ process identifier index 2  (4)

The UE receives a signaling indicating a semi-persistent resource allocation interval in the call setup process. For ease of explanation, the semi-persistent resource allocation interval expressed in units of frames will be referred to herein as “i”. If the semi-persistent resource allocation interval is 20 msec, i is set to 2 (i=2).

After semi-persistent resources are allocated to the UE at an arbitrary time, the UE receives, in step 510, a HARQ packet through semi-persistent resources that periodically come. Upon receiving the HARQ packet through semi-persistent resources, in step 515, the UE calculates a HARQ process index to be applied to the HARQ packet received through semi-persistent resources using Equation (3), and checks a HARQ process identifier indicated by the index. Further, the UE maps the HARQ packet received through semi-persistent resources to the HARQ process identifier. Thereafter, the UE performs CRC calculation on the HARQ packet received through semi-persistent resources in step 520 to check if there is an error in the HARQ packet.

If there is no error, the UE delivers the HARQ packet to an upper layer, and then waits until an HARQ packet is received through the next semi-persistent resources in step 510.

However, if there is an error, in step 525, the UE stores the packet received through semi-persistent resources in the HARQ process corresponding to the HARQ process identifier calculated in step 515, and transmits a negative response signal NACK through a response channel Thereafter, in step 530, the UE monitors an L1/L2 control channel to receive HARQ retransmission. Upon detecting a HARQ packet scheduled thereto, in step 535, the UE checks if the HARQ process identifier of the HARQ packet corresponds to the semi-persistent resource-dedicated HARQ process calculated in step 515. If the HARQ process identifier of the HARQ packet corresponds to the semi-persistent resource-dedicated HARQ process, the UE proceeds to step 545, and otherwise, proceeds to step 540.

In step 540, the UE performs a predetermined necessary operation according to the prior art. That is, the UE determines a HARQ process, a packet stored in which it will soft-combine with the received HARQ packet depending on the HARQ process identifier of the received HARQ packet, checking presence/absence of an error therein, and transmitting HARQ feedback information according to the check result. However, in step 545, the UE soft-combines the received HARQ packet with the data stored in the corresponding semi-persistent resource-dedicated HARQ process. Thereafter, the UE returns to step 520 where it performs an error detection operation. The UE then repeats the HARQ operation until a predetermined condition is satisfied.

Third Embodiment

The third embodiment of the present invention maps an arbitrary HARQ process identifier to a HARQ process where data to be subject to soft-combining is stored, using a relative allocation sequence of semi-persistent resources from the timing at which a semi-persistent resource-dedicated HARQ process identifier is received through an L1/L2 control channel. An ENB and a UE agree to use n HARQ processes for semi-persistent resources, and assign not the absolute identifiers, but relative identifiers to the semi-persistent resource-dedicated HARQ processes. For example, the relative identifier indicates what previous interval, a HARQ packet transmitted though semi-persistent resources in which should be soft-combined with the retransmission HARQ packet.

More specifically, the UE and the ENB agree on the meanings of the semi-persistent resource-dedicated HARQ process identifiers and the HARQ process identifiers in the call setup process, as follows. The agreement is previously made so that a HARQ process x₀ used for semi-persistent resources indicates a HARQ process in which a HARQ packet received through semi-persistent resources allocated in the just previous interval is stored; a HARQ process x₁ means an HARQ process in which an HARQ packet received through semi-persistent resources allocated in the second previous interval is stored; and a HARQ process x₂ means a HARQ process in which an HARQ packet received through semi-persistent resources allocated in a third previous interval is stored.

FIG. 6 is a diagram illustrating a procedure for HARQ-processing semi-persistent resources according to the third embodiment of the present invention.

Referring to FIG. 6, if a UE initially receives an HARQ packet through semi-persistent resource, the UE stores the HARQ packet in an arbitrary HARQ process where no data is stored, among the HARQ processes allocated for semi-persistent resources. Thereafter, the UE can receive retransmission of the HARQ packet at an arbitrary time as illustrated by reference numeral 620. Then the UE checks a HARQ process identifier of the HARQ packet. If the HARQ identifier is x₀ (625), the UE delivers the retransmission HARQ packet to an HARQ process in which an HARQ packet 615 received through the just previous semi-persistent resource is stored. That is, the UE soft-combines the HARQ packet 620 transmitted along with the HARQ process identifier x₀ with the data stored in the HARQ process in which the HARQ packet 615 received through the just previous semi-persistent resource is stored.

If the HARQ identifier is x₁ (630), the UE identifies that the HARQ identifier indicates a HARQ process in which a HARQ packet 610 received through the second previous semi-persistent resource is stored. Then the UE soft-combines the HARQ packet 620 with the data stored in the HARQ process. If the HARQ identifier is x₂ (635), the UE identifies that the HARQ identifier indicates a HARQ process in which a HARQ packet 605 received through the third previous semi-persistent resource is stored. Then the UE soft-combines the HARQ packet 620 with the HARQ packet stored in the HARQ process.

FIG. 7 is a flowchart illustrating an operation for receiving a HARQ packet in a UE according to the third embodiment of the present invention.

Referring to FIG. 7, in a call setup process of step 705, the UE receives a signal including semi-persistent resource-dedicated HARQ processes identifiers and soft-buffer size. When the number of HARQ processes allocated for semi-persistent resources is defined as n, the UE allocates n soft buffers corresponding to the buffer size for semi-persistent resources. The UE receives a signal indicating the meaning of the semi-persistent resource-dedicated HARQ process identifier in the call setup process. That is, the UE receives a signaling including information indicating what previous semi-persistent resource, an identifier of a process associated with which a particular HARQ process identifier corresponds to. The UE identifies n processes x₀, x₁, x₂, . . . , x_n-1 as semi-persistent resource-dedicated HARQ process identifiers, and the meaning of each HARQ process identifier is defined as Equation (5).
HARQ process x₀=process identifier associated with just previous semi-persistent resource
HARQ process x₁=process identifier associated with second previous semi-persistent resource
HARQ process x₂=process identifier associated with third previous semi-persistent resource
HARQ process x_n-1=process identifier associated with n^th previous semi-persistent resource  (5)

If the UE, which has completed the call setup process, is allocated semi-persistent resources at an arbitrary time, the UE receives a HARQ packet through the semi-persistent resources in step 710. Thereafter, the UE performs CRC calculation on the HARQ packet received through the semi-persistent resource in step 715 to check if there is an error in the HARQ packet. If there is no error, the UE delivers the HARQ packet to an upper layer, and then waits until an HARQ packet is received through the next semi-persistent resources in step 710.

However, if there is an error, in step 720, the UE stores the HARQ packet including the error as it is received through the semi-persistent resources, in one of the currently unused semi-persistent resource-dedicated HARQ processes in which no data is stored, and then transmits a NACK signal. Thereafter, in step 725, the UE monitors an L1/L2 control channel to receive HARQ retransmission. If the UE receives a HARQ packet scheduled thereto while monitoring the L1/L2 control channel, the UE checks in step 730 if a HARQ process identifier of the HARQ packet corresponds to any one of the semi-persistent resource-dedicated HARQ processes calculated in step 715. If the HARQ process identifier of the received HARQ packet corresponds to any one of the semi-persistent resource-dedicated HARQ processes, the UE proceeds to step 735, and otherwise, proceeds to step 740.

In step 740, the UE performs a predetermined operation according to the prior art. That is, the UE performs an operation of soft-combining the received HARQ packet with the packet stored in the HARQ process indicated by an HARQ process identifier of the HARQ packet, checking presence/absence of an error therein, and transmitting HARQ feedback information.

However, in step 735, the UE checks the process, a packet associated with which corresponds to the HARQ packet, depending on the HARQ process identifier of the received HARQ packet. That is, if the HARQ process identifier is x_m, the UE identifies that the process identifier indicates a process associated with the m^th previous semi-persistent resource. Therefore, the UE soft-combines the received HARQ packet with the data stored in the process in which the HARQ packet received through the m^th previous semi-persistent resource was stored. Thereafter, the UE returns to step 715 where it performs an error detection operation. The UE repeats the HARQ operation until a predetermined condition is satisfied.

FIG. 8 is a flowchart illustrating an operation for transmitting a HARQ packet through semi-persistent resources in an ENB according to the present invention.

Referring to FIG. 8, in step 805, the ENB allocates semi-persistent resources to a UE to which it should allocate semi-persistent resources, such as VoIP. Thereafter, in step 810, the ENB transmits a HARQ packet to the UE using the semi-persistent resources. In step 815, the ENB determines whether to perform retransmission based on a HARQ feedback received from the UE. That is, the ENB checks a response channel from the UE to determine whether it has received a NACK signal (NACK) or an Acknowledge signal (ACK). If it has received an ACK signal, the ENB transmits an HARQ packet through semi-persistent resources at the next timing in step 810.

However, if the ENB has received a NACK signal, in step 820, the ENB performs a predetermined scheduling algorithm to determine transmission resources for HARQ retransmission. Thereafter, in step 825, the ENB determines an identifier of a HARQ process to be used for retransmission. When the above-described first embodiment is applied, the ENB uses the semi-persistent resource-dedicated HARQ process identifier agreed upon with the UE in the call setup process, for the retransmission. When the second embodiment is applied, the ENB uses, for the retransmission, a HARQ process identifier derived from time information of the timing at which an HARQ packet is transmitted through semi-persistent resources, among the semi-persistent resource-dedicated HARQ process identifiers agreed upon with the UE in the call setup process. When the third embodiment is applied, the ENB selects a proper HARQ process identifier depending on a time difference between the timing at which a retransmission packet is transmitted and the time at which a HARQ packet is transmitted through semi-persistent resources, among the semi-persistent resource-dedicated HARQ process identifiers agreed upon with the UE in the call setup process. In step 830, the ENB retransmits an HARQ packet using the allocated transmission resources and the selected HARQ process identifier. Thereafter, in step 815, the ENB checks if there is a need for another retransmission.

FIG. 9 is a block diagram illustrating an internal structure of a UE apparatus to which the present invention is applied. It should be noted in FIG. 9 that only the elements essential to the present invention are shown and other elements irrelevant to the present invention are not shown for simplicity.

Referring to FIG. 9, the UE apparatus includes an upper layer device 905, a HARQ process 910, in which a normal HARQ processor 913 and a semi-persistent resource-dedicated HARQ processor 915 are included, a transceiver 925, and a controller 920. For each of the HARQ processors 913 and 915, at least one processor is provided in association with the service.

The controller 920 receives L1/L2 control information via the transceiver 925, and receives a HARQ packet using transmission resources identified through the received L1/L2 control information. Further, the controller 920 determines to which HARQ process it will deliver the received HARQ packet. The controller 920, when it receives a HARQ packet through semi-persistent resources, stores it in a HARQ process allocated for semi-persistent resources. That is, the controller 920 determines on which packet the corresponding retransmission is made, for the HARQ packet received through semi-persistent resources, depending on the HARQ process identifier acquired through an L1/L2 control channel, and controls the transceiver 925 so that the retransmitted HARQ packet is delivered to a proper HARQ process. In other words, the controller 920 controls the transceiver 925 so that it receives a retransmission packet having a semi-persistent resource-dedicated HARQ process identifier agreed upon in the call setup process according to the first embodiment.

Further, the controller 920 controls the transceiver 925 so that it receives a retransmission packet by checking a HARQ process identifier derived from time information of the timing at which a HARQ packet is transmitted through semi-persistent resources using the information acquired in the call setup process according to the second embodiment.

In addition, the controller 920 controls the transceiver 925 to select a HARQ process identifier depending on a time difference between the time at which a retransmission packet is transmitted and the time at which an HARQ packet is transmitted through semi-persistent resources according to the third embodiment, and receives a retransmission packet having the selected identifier.

Moreover, according to the fourth embodiment, the controller 920 detects an identifier through a relation with the semi-persistent resource allocation timing, using a Retransmission Sequence Number (RSN) signaled from an ENB, and selects a HARQ process associated with the corresponding identifier.

The transceiver 925 receives L1/L2 control information or a HARQ packet through a wireless channel. Generally, the transceiver 925 can include a Radio Frequency (RF) unit, an antenna, and a modem.

The HARQ process 910 includes soft buffers provided for performing a HARQ operation, and is identified by a HARQ process identifier. Therefore, the HARQ process 910 can be implemented with a memory. The semi-persistent resource-dedicated HARQ processor 915 stores therein the HARQ packet associated with semi-persistent resources.

The upper layer device 905 is for receiving the packet successfully received in the HARQ process, and performing a predetermined operation thereon.

FIG. 10 is a block diagram illustrating an internal structure of an ENB apparatus according to the present invention.

Referring to FIG. 10, the ENB apparatus includes an upper layer device 1005, a HARQ layer device (or HARQ process) 1010 in which a normal HARQ processor 1013 and a semi-persistent resource-dedicated HARQ processor 1015 are included, a transceiver 1025, a scheduler and control channel processor 1020, and a semi-persistent resource-dedicated HARQ process identifier manager 1030.

The scheduler and control channel processor 1020 allocates transmission resources to a UE through a predetermined scheduling operation, generates L1/L2 control information, and transmits it to the UE. The scheduler and control channel processor 1020 receives an HARQ process identifier notified from the semi-persistent resource-dedicated HARQ process identifier manager 1030 during retransmission on a HARQ packet to be transmitted through semi-persistent resources.

The semi-persistent resource-dedicated HARQ process identifier manager 1030 manages identifiers of HARQ processes allocated for semi-persistent resources. The semi-persistent resource-dedicated HARQ process identifier manager 1030, before execution of retransmission on the HARQ packet to be transmitted through semi-persistent resource, selects a semi-persistent resource-dedicated HARQ process identifier to be used, and notifies it to the scheduler and control channel processor 1020. That is, the semi-persistent resource-dedicated HARQ process identifier manager 1030 uses, for the retransmission, a semi-persistent resource-dedicated HARQ process identifier agreed upon in the call setup process according to the first embodiment of the present invention.

When the second embodiment is applied, the semi-persistent resource-dedicated HARQ process identifier manager 1030 uses, for the retransmission, a HARQ process identifier derived from time information of the timing at which a HARQ packet is transmitted through semi-persistent resources, among the semi-persistent resource-dedicated HARQ process identifiers agreed upon in the call setup process.

When the third embodiment is applied, the ENB selects a proper HARQ process identifier among the semi-persistent resource-dedicated HARQ process identifiers agreed upon with the UE in the call setup process, depending on a time difference between the timing at which a retransmission packet is transmitted and the timing at which a HARQ packet is transmitted through semi-persistent resources.

In the fourth embodiment, the semi-persistent resource-dedicated HARQ process identifier manager 1030 selects an identifier using RSN based on a relation with the semi-persistent resource allocation timing.

The transceiver 1025 is a device for transmitting L1/L2 control information or a HARQ packet through a wireless channel. The transceiver 1025 can include an antenna, an RF unit, and a modem. The HARQ process 1010 includes soft buffers provided for performing a HARQ operation, and can be implemented with a memory. The soft buffers are identified by HARQ process identifiers. The semi-persistent resource-dedicated HARQ processor 1015 processes only the HARQ packet associated with semi-persistent resources.

The upper layer device 1005 is for receiving a packet successfully received in the HARQ process 1010, and performing a predetermined operation thereon.

Fourth Embodiment

The fourth embodiment of the present invention provides a method for identifying a HARQ process in which a packet to be subject to soft-combining is stored, using other information rather than the HARQ process identifier. The fourth embodiment of the present invention indicates a HARQ process identifier using the soft-combining-related information like the RSN.

RSN is information indicating the sequence of HARQ retransmission. The fourth embodiment of the present invention restricts an RSN range available for a predetermined interval, thereby determining one of several HARQ processes, data stored in which should be soft-combined with the received data, using an RSN value of the received data. For example, in a system where 8 RSN code points r₁-r₈ are defined, an RSN for retransmission of an HARQ packet received through semi-persistent resources at an arbitrary timing is determined according to the rule defined as shown in Equation (6).
RSN=r₁,r₂ which can be used until the timing at which the first semi-persistent resource is allocated after semi-persistent resources
RSN=r₃,r₄ which can be used until the timing at which the second semi-persistent resource is allocated after semi-persistent resources
RSN=r₅,r₆ which can be used until the timing at which the third semi-persistent resource is allocated after semi-persistent resources
RSN=r₇,r₈ which can be used until the timing at which the fourth semi-persistent resource is allocated after semi-persistent resources  (6)

Upon successfully in decoding an L1/L2 control channel at an arbitrary timing, the UE checks a HARQ process identifier in the L1/L2 control channel, and if the HARQ process identifier indicates retransmission for the data received through semi-persistent resources, the UE checks an RSN of the L1/L2 control channel. If the RSN is r₁ or r₂ (1125), because the data indicates retransmission for the data 1115 received through semi-persistent resources at the nearest semi-persistent resource allocation timing, the UE soft-combines it with the data 1115 received through the nearest semi-persistent resources. If the RSN is r₃ or r₄ (1130), because the data indicates retransmission for the data 1110 received through semi-persistent resources at the second previous semi-persistent resource allocation timing from the current timing, the UE soft-combines it with the data 1110 received through the second previous semi-persistent resource from the current one. If the RSN is r₅ or r₆ (1135), because the data indicates retransmission for the data 1105 received through semi-persistent resources at the third previous semi-persistent resource allocation timing from the current timing, the UE soft-combines it with the data 1105 received through the third previous semi-persistent resource allocation timing from the current timing.

FIG. 12 is a flowchart illustrating an operation of receiving a HARQ packet in a UE according to the fourth embodiment of the present invention.

Referring to FIG. 12, in the call setup process of step 1205, the UE receives a signaling including a HARQ process identifier indicating a semi-persistent resource-dedicated HARQ process, the number and soft-buffer size of semi-persistent resource-dedicated HARQ processes, and an available interval of RSN. More specifically, when the number of HARQ processes allocated for semi-persistent resources is defined as n, the UE allocates n soft buffers corresponding to the buffer size for semi-persistent resources.

In addition, the UE receives a signaling including an identifier of a semi-persistent resource-dedicated HARQ process in the call setup process. The number of the identifiers is always one, regardless of the number of HARQ processes allocated for semi-persistent resources, and the semi-persistent resource-dedicated HARQ process identifier only indicates that the data received at an arbitrary timing is retransmission for the data received through semi-persistent resources, and RSN/retransmission mapping information indicates the HARQ process, retransmission for the data stored in which the received data corresponds to.

The UE receives a signaling including information by which it can identify a semi-persistent resource-dedicated HARQ process, i.e., the information on a relation between the RSN and the semi-persistent resource allocation timing, in the call setup process. This information indicates what previous semi-persistent resource allocation timing, retransmission for a packet received through semi-persistent resources in which an arbitrary RSN x is used for. This information is will be referred to herein as RSN/retransmission mapping information. In this case, when there are n RSNs of r₁ to r_n, the RSN/retransmission mapping information can be generated as defined in Equation (7).
r₁: It is used for retransmission on a packet received through semi-persistent resources at the just previous semi-persistent resource allocation timing
r_m: It is used for retransmission on a packet received through semi-persistent resources at the x^th previous semi-persistent resource allocation timing
r_n: It is used for retransmission on a packet received through semi-persistent resources at the y^th previous semi-persistent resource allocation timing  (7)

The details of Equation (7) will be described by way of example. Assuming there are 4 RSNs, 0 to 3, the RSN/retransmission mapping information can be generated as defined below.

0: It is used for retransmission on a packet received through semi-persistent resources at the just previous semi-persistent resource allocation timing.

1: It is used for retransmission on a packet received through semi-persistent resources at the just previous semi-persistent resource allocation timing.

2: It is used for retransmission on a packet received through semi-persistent resources at the second previous semi-persistent resource allocation timing.

3: It is used for retransmission on a packet received through semi-persistent resources at the third previous semi-persistent resource allocation timing.

If the UE, which has completed the call setup process, is allocated semi-persistent resources at an arbitrary timing, the UE receives an HARQ packet through the semi-persistent resources in step 1210. Thereafter, the UE performs CRC calculation on the HARQ packet received through semi-persistent resources in step 1215 to check if there is an error in the HARQ packet. If there is no error, the UE delivers the HARQ packet to an upper layer, and waits until an HARQ packet is received through the next semi-persistent resources in step 1210.

If there is an error, in step 1220, the UE receives the HARQ packet through semi-persistent resources, and stores the HARQ packet having an error in one of the currently unused semi-persistent resource-dedicated HARQ processes in which no other data is stored, and then transmits a NACK signal. Thereafter, in step 1225, the UE monitors an L1/L2 control channel to receive HARQ retransmission.

Upon receiving an HARQ packet scheduled thereto, while monitoring the L1/L2 control channel, in step 1230, the UE checks if a HARQ process identifier of the HARQ packet corresponds to the semi-persistent resource-dedicated HARQ process identifier perceived in the call setup process. If the HARQ process identifier of the received HARQ packet indicates the fact that the HARQ packet is retransmission for a HARQ packet received through semi-persistent resources, the UE proceeds to step 1235, and otherwise, proceeds to step 1240.

In step 1240, the UE performs a predetermined operation according to the prior art. That is, the UE performs an operation of soft-combining the received HARQ packet with the packet stored in the HARQ process indicated by the HARQ process identifier of the packet, checking presence/absence of an error therein, and transmitting HARQ feedback information.

However, in step 1235, the UE checks the process, a packet associated with which the HARQ packet corresponds to, depending on the RSN of the received HARQ packet. That is, if RSN is an arbitrary k, the UE checks what previous semi-persistent resource allocation timing, retransmission on a packet received through semi-persistent resources in which is indicated by the k, depending on the RSN/retransmission mapping information, and soft-combines the packet with the received HARQ packet. Thereafter, in step 1215, the UE performs an error detection operation. The UE repeats the HARQ operation until a predetermined condition is satisfied.

As is apparent from the foregoing description, the application of the present invention identifies a packet HARQ-retransmitted through semi-persistent resources. Further, the present invention provides HARQ soft-combining by mapping the packet received through semi-persistent resources to the retransmitted HARQ packet. When there are several HARQ packets received through semi-persistent resources at an arbitrary time, a corresponding processor performs correct soft-combining by determining with which packet an arbitrary retransmission packet should be combined. Therefore, the present invention can prevent the communication failure or unnecessary retransmission caused by the packet perception error. In addition, the present invention can use semi-persistent resource-based HARQ without increasing complexity of the receiver.

While the present invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method for receiving data in a communication system, the method comprising:

acquiring a number of hybrid automatic repeat request (harq) processes of a semi-persistent resource allocation and semi-persistent resource allocation interval information;

identifying the semi-persistent resource allocation for a subframe based on the semi-persistent resource allocation interval information and time information;

acquiring a harq process identifier (id) using the number of harq processes of the semi-persistent resource allocation, the semi-persistent resource allocation interval information, and the time information;

acquiring soft buffer information; and

receiving data based on the semi-persistent resource allocation for the subframe, the harq process id, and the soft buffer information.

2. The method of claim 1, further comprising setting the acquired harq process id to a harq process id for the subframe.

3. The method of claim 1, wherein the time information includes a system frame number (SFN) and a sub-frame number.

4. The method of claim 1, wherein the harq process id is acquired based on:

harq process ID=s modulo n,

where s is an integer derived from t/i, wherein t represents the time information, i represents the semi-persistent resource allocation interval information, and n represents the number of harq processes of the semi-persistent resource allocation.

5. A method for transmitting data in a communication system, the method comprising:

transmitting information representative of a number of hybrid automatic repeat request (harq) processes of a semi-persistent resource allocation and semi-persistent resource allocation interval information;

allocating the semi-persistent resource for a subframe based on the semi-persistent resource allocation interval information and time information;

acquiring a harq process identifier (id) using the number of harq processes of the semi-persistent resource allocation, the semi-persistent resource allocation interval information, and the time information;

transmitting soft buffer information; and

transmitting data based on the semi-persistent resource allocation for the subframe, the harq process id, and the soft buffer information.

6. The method of claim 5, further comprising setting the acquired harq process id to a harq process id for the subframe.

7. The method of claim 5, wherein the time information includes a system frame number (SFN) and a sub-frame number.

8. The method of claim 5, wherein the harq process id is acquired based on:

harq process ID=s modulo n,

wherein s is an integer derived from t/i, t represents the time information, i represents the semi-persistent resource allocation interval information, and n represents the number of harq processes of the semi-persistent resource allocation.

9. An apparatus for receiving data in a communication system, the apparatus comprising:

a controller configured to

acquire a number of hybrid automatic repeat request (harq) processes of a semi-persistent resource allocation and semi-persistent resource allocation interval information,

identify the semi-persistent resource allocation for a subframe based on the semi-persistent resource allocation interval information and time information,

acquire a harq process identifier (id) using the number of harq processes of the semi-persistent resource allocation, the semi-persistent resource allocation interval information, and the time information; and

a receiver configured to receive data based on the semi-persistent resource allocation for the subframe, the harq process id, and the soft buffer information.

10. The apparatus of claim 9, wherein the controller is further configured to set the acquired harq process id to a harq process id for the subframe.

11. The apparatus of claim 9, wherein the time information includes a system frame number (SFN) and a sub-frame number.

12. The apparatus of claim 9, wherein the harq process id is acquired based on:

harq process ID=s modulo n,

wherein s is an integer derived from t/i, t represents the time information, i represents the semi-persistent resource allocation interval information, and n represents the number of harq processes of the semi-persistent resource allocation.

13. An apparatus for transmitting data in a communication system, the apparatus comprising:

a transmitter configured to transmit information representative of a number of hybrid automatic repeat request (harq) processes of a semi-persistent resource allocation and semi-persistent resource allocation interval information, transmit soft buffer information, and transmit data based on the semi-persistent resource allocation for a subframe, the harq) process id, and the soft buffer information; and

a controller configured to allocate the semi-persistent resource for the subframe based on the semi-persistent resource allocation interval information and time information, and acquire a harq process identifier (id) using the number of harq processes of the semi-persistent resource allocation, the semi-persistent resource allocation interval information, and the time information.

14. The apparatus of claim 13, wherein the controller is further configured to set the acquired harq process id to a harq process id for the subframe.

15. The apparatus of claim 13, wherein the time information includes a system frame number (SFN) and a sub-frame number.

16. The apparatus of claim 13, wherein the harq process id is acquired based on:

harq process ID=s modulo n,

wherein s is an integer derived from t/i, t represents the time information, i represents the semi-persistent resource allocation interval information, and n represents the number of harq processes of the semi-persistent resource allocation.

17. A method for receiving data in a communication system, the method comprising:

acquiring information on a quantity of hybrid automatic repeat request (harq) processes for a semi-persistent resource allocation and information indicating an interval of resources for the semi-persistent resource allocation, wherein consecutive harq process identifiers (ids) from 0 to N−1 are used for the semi-persistent resource allocation in case that the quantity of harq processes for the semi-persistent resource allocation is N;

identifying a harq process id by using the quantity of harq processes for the semi-persistent resource allocation, the interval for the semi-persistent resource allocation, and a system frame number; and

receiving data for an initial transmission, associated with the semi-persistent resource allocation, corresponding to the identified harq process id.

18. The method of claim 17, wherein resource information for the semi-persistent resource allocation is acquired at a timing of data reception.

19. The method of claim 17, wherein the harq process id is identified based on a modulo function for the interval for the semi-persistent resource allocation and the system frame number by the quantity of harq processes for the semi-persistent resource allocation.

20. The method of claim 17, further comprising identifying a size of a soft buffer for the data.

21. A method for transmitting data in a communication system, the method comprising:

transmitting information representative of a quantity of hybrid automatic repeat request (harq) processes for a semi-persistent resource allocation and information indicating an interval of resources for the semi-persistent resource allocation, wherein consecutive harq process identifiers (ids) from 0 to N−1 are used for the semi-persistent resource allocation in case that the quantity of harq processes for the semi-persistent resource allocation is N; and

transmitting data for an initial transmission, associated with the semi-persistent resource allocation, corresponding to a harq process id,

wherein the harq process id is based on the quantity of harq processes for the semi-persistent resource allocation, the interval for the semi-persistent resource allocation, and a system frame number.

22. The method of claim 21, wherein resource information for the semi-persistent resource allocation is acquired at a timing of data transmission.

23. The method of claim 21, wherein the harq process id is identified based on a modulo function for the interval for the semi-persistent resource allocation and the system frame number by the quantity of harq processes for the semi-persistent resource allocation.

24. The method of claim 21, further comprising identifying a size of a soft buffer for the data.

25. An apparatus for receiving data in a communication system, the apparatus comprising:

a controller configured to:

acquire information on a quantity of hybrid automatic repeat request (harq) processes for a semi-persistent resource allocation and information indicating an interval of resources for the semi-persistent resource allocation, wherein consecutive harq process identifiers (ids) from 0 to N−1 are used for the semi-persistent resource allocation in case that the quantity of harq processes for the semi-persistent resource allocation is N, and

identify a harq process id by using the quantity of harq processes for the semi-persistent resource allocation, the interval for the semi-persistent resource allocation, and a system frame number; and

a receiver configured to receive data for an initial transmission, associated with the semi-persistent resource allocation, corresponding to the identified harq process id.

26. The apparatus of claim 25, wherein resource information for the semi-persistent resource allocation is acquired at a timing of data reception.

27. The apparatus of claim 25, wherein the harq process id is identified based on a modulo function for the interval for the semi-persistent resource allocation and the system frame number by the quantity of harq processes for the semi-persistent resource allocation.

28. The apparatus of claim 25, wherein the controller is further configured to identify a size of a soft buffer for the data.

29. An apparatus for transmitting data in a communication system, the apparatus comprising:

a transmitter configured to:

transmit information representative of a quantity of hybrid automatic repeat request (harq) processes for a semi-persistent resource allocation and information indicating an interval of resources for the semi-persistent resource allocation, wherein consecutive harq process identifiers (ids) from 0 to N−1 are used for the semi-persistent resource allocation in case that the quantity of harq processes for the semi-persistent resource allocation is N, and

transmit data for an initial transmission, associated with the semi-persistent resource allocation, corresponding to a harq process id,

wherein the harq process id is based on the quantity of harq processes for the semi-persistent resource allocation, the interval for the semi-persistent resource allocation, and a system frame number.

30. The apparatus of claim 29, wherein resource information for the semi-persistent resource allocation is acquired at a timing of data transmission.

31. The apparatus of claim 29, wherein the harq process id is identified based on a modulo function for the interval for the semi-persistent resource allocation and the system frame number by the quantity of harq processes for the semi-persistent resource allocation.

32. The apparatus of claim 29, wherein the controller is further configured to identify a size of a soft buffer for the data.