KR100780474B1 - Communication method, packet radio system, controller and user terminal - Google Patents

Abstract

The present invention is a communication method. Packet radio system, controller and user terminal. The packet radio system includes a controller 146, a user terminal 170 and one or more base stations 142, 144 in communication with the user terminal and the controller of the packet radio system. The processing unit 226 of the controller is further configured to define a subset of the soft handover active set based on the capabilities of the base stations of the active set as well as provide information as to whether the base stations are included in the defined subset, and the user The processing unit 220 of the terminal is further configured to monitor the HARQ information from only the base stations included in the defined subset.

Soft handover, packet radio system, HARQ information, uplink signal.

Description

Communication method, packet radio system, controller and user terminal {COMMUNICATION METHOD, PACKET RADIO SYSTEM, CONTROLLER AND USER TERMINAL}

The present invention is a communication method in a wireless packet system. A packet radio system, a controller for a packet radio system, and a user terminal for a packet radio system.

There are different approaches to Hybrid Automatic Repeat reQuest (HARQ) in soft handover situations. In one possible manner, each Node B in the soft handover active set receives data from the user terminal and sends an ACK / NACK (positive acknowledgment / negative acknowledgment) to the user terminal. If the user terminal does not receive any ACK from any Node B in the soft handover active set, retransmission occurs. If at least one ACK is received, new data is sent instead. For macro diversity gain and chase combining, this approach provides good performance when ACK / NACK signaling is free of errors.

Soft handover decisions are based on measurements of a DL CPICH (downlink common pilot channel) channel. Since the uplinks quality between the user terminal and the different Node Bs are not checked, the quality in soft handover cannot be guaranteed. In the '99 publication, for example, more Node Bs in the active set always mean more soft handover gains regardless of the individual gains of each Node B. In enhanced uplink packet access (EUPA), when HARQ is used, the more Node Bs, the more signaling and also possible signaling errors. EUPA is introducing Node B scheduling for improvements in throughput and reduction of delays and improvements in uplink such as L1-ARQ (physical layer automatic repeat request). Signaling errors (eg, NACK recognized as ACK) result in adverse effects in HARQ operations.

In the downlink direction, ACK / NACK signaling does not benefit from soft handover gain, which means an increase in the probability of error, especially for the worst links in the set. The effects of errors in this ACK / NACK recognition can be very detrimental. For example, if all Node Bs send a NACK and one of the NACKs is decrypted by the user terminal as an ACK, new data is sent, resulting in RLC (Radio Link Control) ARQ retransmission. Moreover, the delay gain of L1-HARQ is lost. Conversely, if all ACKs are received as NACK, unnecessary retransmissions occur and the delay increases. In the uplink direction, uplink signaling errors can result in unsynchronized HARQ being handled at different Node Bs.

The presence of Node Bs with poor uplink performance (uplink imbalance) in the soft handover active set does not result in any valuable soft handover gain. Moreover, the HARQ signaling error of Node Bs with such poor uplink performance can still cause harmful results. Thus, when HARQ is used in EUPA, more Node Bs in the active set do not always mean improved performance.

Regarding the ACK / NACK recognition error, different attempts have been made to overcome the problem. One attempt is to increase the energy of the ACK / NACK. However, user terminals may not have enough Rake fingers for all Node Bs, so even an increase in ACK / NACK energy does not guarantee that all ACK / NACKs are correctly received. Another solution is to decode ACK / NACK from only sufficiently strong Node Bs (in downlink signal strength). However, uplink macro diversity gain may be lost when one Node B has a good uplink connection but poor downlink signal strength. Another alternative solution is for each Node B to send an ACK / NACK to the Radio Network Controller (RNC) first, after which the RNC generates a combined result of the ACK / NACK, which is sent to each Node B. As a result, the user terminal can combine all ACK / NACKs from the Node Bs. However, this operation requires some additional delay of Node B from the RNC, which is contrary to HARQ purposes.

According to one aspect of the present invention, there is provided a communication method using a hybrid automatic retransmission request (HARQ) in a packet radio system, wherein the method is based on the capability of base stations in an active set by a controller of a server in a soft handover active set. Defining a set; Providing information as to whether the base stations are included in the defined subset; And monitoring, by the user terminal, HARQ information received from only base stations included in the defined subset.

According to one embodiment of the invention, there is provided a packet radio system using a hybrid automatic retransmission request (HARQ), wherein the packet radio system is configured to control radio resources of a packet radio system, wherein the controller is a packet A transceiver for communicating with a user terminal and one or more base stations of a wireless system, and a processing unit for controlling controller functions; A user terminal, wherein the user terminal comprises a transceiver in communication with a controller in the packet radio system and one or more base stations, and a processing unit for controlling user terminal functions; And one or more base stations in communication with a controller and a user terminal of a packet radio system. The processing unit of the controller is further configured to define a subset of the soft handover active set based on the capabilities of the base stations of the active set as well as to provide information as to whether the base stations are included in the defined set, and the processing of the user terminal. The unit is further configured to monitor the HARQ information received from only the base stations included in the defined subset.

According to one embodiment of the invention, there is provided a controller for a packet radio system using a hybrid automatic retransmission request (HARQ), the controller comprising: a transceiver for communicating with one or more base stations and user terminals of the packet radio system; And a processing unit for controlling the controller functions. The processing unit of the controller defines a subset of the soft handover active set based on the capabilities of the base stations of the active set and provides information as to whether the base stations are included in the defined subset, thereby causing the user terminal to It is further configured to be able to monitor HARQ information received from only base stations included in the defined subset.

According to one embodiment of the present invention, a user terminal for a packet radio system using an automatic retransmission request (HARQ) is provided, the user terminal comprising a transceiver for communicating with a controller and one or more base stations of the packet radio system; and A processing unit for controlling user terminal functions. The processing unit is further configured to monitor the HARQ information received from only the base stations included in the subset defined by the controller based on the capabilities of the base stations of the soft handover active set.

According to one embodiment of the present invention, a packet radio system using an automatic retransmission request (HARQ) is provided, the packet radio system comprising a controller controlling one or more base stations of a packet radio system, wherein the controller is a packet radio Communication means for communicating with a user terminal and one or more base stations of the system; A user terminal comprising a controller in a packet radio system and communication means for communicating with one or more base stations; And one or more base stations including communication means for communicating with a controller and a user terminal of a packet radio system. The controller further comprises defining means for defining a subset of the soft handover active set based on the capabilities of the base stations of the active set, and indicating means for providing information as to whether the base stations are included in the defined subset. The user terminal further includes monitoring means for monitoring HARQ information received from only base stations included in the defined subset.

According to an embodiment of the present invention, there is provided a controller for a packet radio system using an automatic retransmission request (HARQ), the controller comprising: communication means for communicating with one or more base stations and user terminals of the packet radio system; And control means for controlling the controller functions. The control means provides definition means for defining a subset of the soft handover active set based on capabilities of base stations in the active set, and information as to whether the base stations are included in the defined subset, to the user terminal. Indicator means for enabling the monitoring of HARQ information received from only base stations included in the defined subset.

According to an embodiment of the present invention, a user terminal for a packet radio system using an automatic retransmission request (HARQ) is provided, the user terminal comprising: communication means for communicating with a controller and one or more base stations of the packet radio system; And control means for controlling user terminal functions. The control means is further configured to monitor the HARQ information received from only the base stations included in the subset defined by the controller based on the base station capabilities of the soft handover active set.

Embodiments of the present invention provide several advantages. The traffic load of the packet radio system is simultaneously reduced without losing the main soft handover gain.

In the following, the invention will be explained in more detail with reference to preferred embodiments and the accompanying drawings.

1 is an example of a packet radio system.

2 is another example of a packet radio system.

3 is an example of a communication method in a packet radio system.

4 is another example of a communication method in a packet radio system.

Referring to Fig. 1, an example of a packet radio system to which preferred embodiments of the present invention can be applied is shown. The packet radio system of FIG. 1, known at least as UMTS (Universal Mobile Communications System) and IMT-2000 (International Mobile Communicationss 2000), represents third generation wireless systems. However, embodiments are not limited to these systems described by way of example, and those skilled in the art may also apply the present descriptions to other wireless systems that include corresponding features.

1 is a simplified block diagram illustrating the most important parts of a packet radio system and the interfaces between them at the network element level. Because they are generally known, the structure and functions of network elements are not described in detail.

The main parts of a packet radio system are the core network (CN) 100, the radio access network 130 and the user terminal (UE) 170. The term UTRAN is an abbreviation for UMTS terrestrial radio access network, ie radio access network 130 belongs to the third generation and is performed by wideband code division multiple access (WCDMA) technology. The main elements of the UTRAN are the radio network controller (RNC) 146 and 156, the Node Bs 142, 144, 152 and 154 and the user terminal 170. The UTRAN is attached to the existing GSM core network 100 via an interface called Iu. This interface is supported by RNCs 146 and 156 which manage a set of base stations called Node Bs 142, 144, 152 and 154 via interfaces called Iub. The UTRAN is highly autonomous from the core network 100 because the RNCs 146 and 156 are interconnected by an Iur interface.

In view of the Node Bs 142, 144, 152 and 154, ie the base station, there is one control RNC 146 and 156, where the Iub interface terminates. The control RNCs 146 and 156 are also responsible for admission control for new moves or services that wish to use the Node Bs 142, 144, 152 and 154. Control RNC 146 and 156 and their Node Bs 142, 144, 152 and 154 form RNS (Wireless Network Subsystem) 140 and 150.

User terminal 170 may include a mobile equipment (UE) 172 and a UMTS subscriber identification module (USIM) 174. USIM 174 includes information related to the user and information security, particularly information related to, for example, encryption algorithms. In UMTS networks, user terminal 170 may be connected to a plurality of Node Bs at the same time when a soft handover occurs.

In terms of user terminal 170, there is one serving RNC 146 and 156 that terminates link layer communications of mobile devices. In terms of core network 100, serving RNCs 146 and 156 terminate Iu for this user terminal 170. The serving RNCs 146 and 156 also perform subscription control for new mobile devices or services that wish to use the core network 100 via the lu interface. Subscription control ensures that mobile devices are assigned only radio resources (bandwidth and signal / noise ratio) available in the network.

In UMTS, the most important interfaces between network elements are the Iu interface between the core network 100 and the radio access network 130 and the Uu interface between the radio access network and the user terminal.

In the following, a packet radio system will be described by FIG. 2 shows a simplified packet radio system including a user terminal 170, two base stations 142 and 144, and a wireless network controller 146. The first base station 142 includes a transceiver 202, an antenna 204 and a processing unit 200. Similarly, the second base station 144 includes a transceiver 212, an antenna 214 and a processing unit 210. The radio network controller 146 also includes a transceiver 228 and a processing unit 226. The user terminal 170 includes an antenna 224, a transceiver 222, and a processing unit 220 for establishing a wireless connection.

In existing wireless systems, wireless connections are established by user terminals and base stations that communicate with each other via a wireless connection, that is, call or data transfer connections between different terminals are established through base stations. This is illustrated by wireless connections 208 and 218 in FIG. 2.

Processing units 200, 210, 220, and 226 refer to blocks that control device functions, which are currently typically implemented as a processor and its software, but circuitry formed from various hardware solutions, eg, logic components. Or one or more application-specific integrated circuits (ASICs) are also feasible. Hybrids of these different implementations are also feasible.

The user terminal 170 may periodically send channel quality indicator (CQI) reports to the Node Bs 142 and 144 to indicate the currently supported data rates at certain packet error thresholds. The CQI report indicates the number of multicodes that the user terminal can support under coding and modulation schemes and current radio conditions. The user terminal 170 monitors HARQ information including ACK / NACK from Node Bs 142 and 144. Moreover, user terminal 170 also transmits an acknowledgment message (ACK / NACK) for each packet to indicate when to initiate retransmissions. In the channel quality measurements available for each user of the cell, the Node B's packet scheduler can optimize scheduling between users.

In one embodiment, the processing unit 226 of the wireless network controller 146 defines the subset of the soft handover active set based on the capabilities of all the Node Bs in the active set, as well as the Node Bs 142 and 144. Is included in the defined active set. The processing unit 220 of the user terminal 170 is configured to monitor the HARQ information from only the Node Bs 142 and 144 included in the later defined subset.

Accordingly, the user terminal 170 monitors the HARQ process including ACK / NACK of only the Node Bs of the defined subset, not the Node Bs of the entire active set.

The subset can typically be defined to include, for example, one or more Node Bs 142 and 144 from the active set. However, it is also possible for the subset to be defined such that it does not include any Node Bs 142 and 144 from the active set. If the subset is defined not to include any Node Bs 142 and 144, the HARQ procedure may be suspended during soft handover in these situations.

In one embodiment, the wireless network controller 146 is configured to determine which Node Bs 142 and 144 should be in a subset. In one embodiment, wireless network controller 146 includes in the subset Node Bs 142 and 144 with good uplink performance based on uplink measurement reports received from Node Bs 142 and 144. Choose to Thus, a major soft handover gain can be achieved with this subset, and the user terminal needs to listen to fewer ACK / NACKs, which is beneficial.

In one embodiment, the wireless network controller 146 is configured to define a subset based on the downlink capabilities measurements. The wireless network controller 146 may receive measurement reports, such as CQI information, from the user terminal 170. In another embodiment, both uplink and downlink performance measurements are used when defining a subset.

The Node Bs 142 and 144 included in the subset may have normal HARQ procedures, and the user terminal 170 receives and monitors HARQ information transmitted by the Node Bs 142 and 144 in the subset. . On the other hand, Node Bs 142 and 144 that are in a soft handover active set but outside the subset may still decrypt the uplink data and transmit it to the wireless network controller 146 as before. Regarding their ACK / NACK operation, different alternatives may be selected. In one embodiment, Node Bs 142 and 144 outside the subset still send ACK / NACK to user terminal 170, but user terminal 170 does not decrypt them. In an alternate embodiment, Node Bs 142 and 144 outside the subset may stop transmitting HARQ information including ACK / NACK. The latter alternative requires that the determination of the subset need to be sent by the Node Bs 142 and 144 to the user terminal 170, so that each Node B can know whether it is included in the subset. It is possible because there is. The latter alternative means the reduction of unnecessary interference to the wireless system.

In one embodiment, for an update of each active set, wireless network controller 146 is configured to check whether new Node Bs of the active set should be included in the subset. The wireless network controller 146 may, for example, send an update check result with a soft handover active set update command. With regard to subset updates, such updates may also be event-triggered, similar to active set updates.

The wireless network controller 146 is configured to use certain algorithms and thresholds to make the necessary decisions when defining a subset based on uplink and / or downlink measurement reports. Measurement reports may include, for example, signal-to-noise ratio (EbNo) or other thresholds. In one embodiment, when the measured signal-to-noise ratio of one Node B is lower than the noise ratio of Node B, which is the strongest by a certain amount relative to the signal-to-noise ratio of Node B, which is the strongest, this Node B is an example For example, it is not included in the subset. For example, when the signal-to-noise ratio of the first Node B 142 is 3 dB lower than the signal-to-noise ratio of the strongest Node B 144, the first Node B 142 is included in the subset. It doesn't work. The reason for this is that the weak Node B contributes small, and the user terminal 170 is unlikely to follow the HARQ information of this Node B.

In one embodiment, the wireless network controller 146 is configured to add at least one additional subset update command. This command informs the user terminal 170 as to which Node Bs 142 and 144 of the active set should be included in the subset. The update of the subset can be event-triggered. The trigger source can be, for example, a new radio network controller 146 decision on the subset.

With regard to setting up and updating the soft handover active set, two alternative approaches may be selected. In one embodiment, at least one bit is added to the current soft handover active set command and to the soft handover active set update command to indicate whether new Node Bs 142 and 144 should be included in the subset. In another embodiment, the subset update command is sent immediately after the active set set command or the update command.

In one embodiment, Node Bs 142 and 144 outside the subset may stop transmitting HARQ information. Node Bs 142 and 144 may use discontinuous transmission (DTX) to stop transmitting HARQ information. Thus, there is no need to provide the user terminal 170 with information about the Node Bs 142 and 144 included in the subset, and in one embodiment, the Node Bs 142 only in the Node Bs 142 and 144. And information about whether 144 is included in the defined subset.

In one embodiment, the user terminal 170 follows the subset commands to determine whether to listen for ACK / NACK, for example. In one embodiment, the subset of Node Bs 142 and 144 may increase the ACK / NACK energy for good performance. This is possible because small, unnecessary Node Bs 142 and 144 are not included, and therefore a smaller number of ACK / NACKs must be received by the user terminal 170.

It is also possible that all Node Bs 142 and 144 of the active set are defined to be included in the subset. Thus, because all Bs are also included in the subset, user terminal 170 monitors all Node Bs in the active set. In one embodiment, only primary Node Bs 142 and 144 are included in the subset. Thus, only HARQ information of the primary Node Bs 142 and 144 is monitored by the user terminal 170.

3 illustrates one embodiment of a communication method using hybrid automatic retransmission request (HARQ) in a packet radio system. The method begins at 300. In step 302, a subset of the active set of soft handover is defined based on the capabilities of all base stations of the active set. Defining a subset may be based on uplink performance levels or uplink and / or downlink measurement reports of active set base stations. In step 304, information is provided to the user terminal as to whether the base stations should be included in the defined subset. In step 306, the user terminal receives HARQ information from the base stations, and in step 308, the HARQ information from only the base stations included in the defined subset is monitored. Thus, the user terminal can still receive HARQ information from all base stations in the active set, but does not decrypt HARQ information from base stations outside the subset, for example. The method ends at 310.

4 illustrates another embodiment of a communication method in a packet wireless system. The method begins at 400. In step 402, a subset is defined to include, for example, one or more base stations from the soft handover active set based on all base station capabilities of the active set. Defining the subset may be based on uplink performance levels or uplink and / or downlink measurement reports of base stations in the active set. In step 404, information is provided to the user terminal as to whether the base stations should be included in the defined subset. Since information as to whether the base stations should be included in the subset is transmitted to the user terminal via the base stations, the base stations may also have information as to whether they should be included in the subset. In step 406, the user terminal receives HARQ information from only the base stations included in the subset. Base stations outside the subset may have, for example, stopped transmitting their HARQ information to the user terminal. In step 404, information as to whether the base stations are included in the defined subset may not be provided to the user terminal at all. At this time, for example, only base stations included in the subset transmit HARQ information to the user terminal. Thus, in step 408, HARQ information from only the base stations included in the defined subset is monitored. The method ends at step 410.

Although the invention has been described with reference to examples in accordance with the accompanying drawings, it is clear that the invention is not limited thereto and may be modified in many ways within the scope of the following claims.

Claims (34)

In a packet radio system, a communication method using a hybrid automatic repeat reQuest (HARQ), Defining, by the controller, a subset of the soft handover active set based on the base station capabilities of the active set (302); Providing (304) information as to whether base stations are included in the subset; And Monitoring, by a user terminal, HARQ information received from only base stations included in the subset (308). 2. The method of claim 1, wherein defining the subset is further based on at least one of uplink and downlink measurement reports. 3. The method of claim 2, wherein defining the subset is further based on uplink performance levels of base stations in an active set. 3. The packet radio of claim 2, wherein the defining step includes defining a subset based on at least one of the uplink and downlink measurement reports comprising channel quality indicator (CQI) reports. Communication method in the system. The method of claim 1, Transmitting HARQ information from base stations in a soft handover active set to the user terminal; And And transmitting information to the user terminal as to which base stations are included in the subset. The method of claim 1, Transmitting information regarding which base stations are included in the subset to base stations in an active set; And Terminating transmission of the HARQ information from the base stations excluded from the subset to the user terminal. The method of claim 1, When the new base stations to be included in the subset are detected in the soft handover active set, updating the subset. 2. The method of claim 1, wherein defining the subset is further based on measurements of at least one of signal-to-noise ratio and other thresholds of base stations in the active set. . The method of claim 8, When the signal-to-noise ratio of a given base station is lower by a predetermined amount than the signal-to-noise ratio of the strongest base station of the active set, further comprising defining the given base station to be excluded from the subset. A communication method in a packet radio system. The method of claim 1, Generating at least one additional subset update command to indicate to the user terminal whether base stations of an active set are included in the subset. The method of claim 1, Adding at least one additional bit to the current soft handover activation set command and to the soft handover active set update command to indicate that a given base station should be included in the subset. A communication method in a packet radio system. The method of claim 10, Transmitting a subset update command after at least one of an active set set command and an active set update command. A packet radio system using hybrid automatic retransmission request (HARQ), A controller for controlling radio resources of a packet radio system, wherein the controller is a transceiver 228 in communication with at least one base station and a user terminal of the packet radio system, and a first processing unit for controlling the functions of the controller. 226; A user terminal 170, wherein the user terminal comprises a transceiver 222 in communication with the at least one base station and the controller of the packet radio system, and a second processing unit for controlling the functions of the user terminal. To; And One or more base stations 142 and 144 in communication with the controller and the user terminal of the packet radio system, Wherein the first processing unit 226 defines a subset of the soft handover active set based on the capabilities of the base stations of the active set and provides information as to which base stations are included in the subset, And the second processing unit (220) monitors HARQ information received from only base stations included in the subset. 14. The packet radio system of claim 13, wherein the first processing unit defines the subset based on at least one of uplink and downlink measurement reports. 14. The apparatus of claim 13, wherein the base stations of a soft handover active set transmit the HARQ information to the user terminal, and the first processing unit transmits information to the user terminal regarding which base stations are included in the subset. Packet wireless system, characterized in that. 14. The apparatus of claim 13, wherein the first processing unit transmits information about which base stations are included in the subset to the base stations and the user terminal in communication with the controller, and base stations excluded from the subset Packet transmission system, characterized in that to terminate the transmission of the HARQ information to the user terminal. 14. The packet radio system of claim 13, wherein the first processing unit updates the subset when new base stations to be included in the subset are detected in a soft handover active set. 14. The packet radio system of claim 13, wherein the first processing unit defines the subset based on measurements of at least one of signal-to-noise ratio and other thresholds of the base stations of an active set. . 19. The method of claim 18, wherein the first processing unit is further configured to cause the given base station to be in the subset when the signal-to-noise ratio of a given base station is lower by a predetermined amount than the signal-to-noise ratio of the strongest base station of the active set. Packet radio system, characterized in that it is defined to be excluded from. 14. The packet radio system of claim 13, wherein the first processing unit generates at least one additional subset update command to indicate to the user terminal whether base stations of an active set are included in the subset. . 14. The apparatus of claim 13, wherein the first processing unit assigns at least one additional bit to a current soft handover activation set command and soft handover active to indicate that a given base station should be included in the subset. A packet radio system, characterized in that it is added to a set update command. A controller for a packet radio system using hybrid automatic retransmission request (HARQ), A transceiver 228 in communication with at least one base station and a user terminal of a packet radio system; And A processing unit 226 for controlling the functions of the controller, Here, the controller processing unit 226 defines a subset of the soft handover active set based on the capabilities of the base stations of the active set and provides information as to which base stations are included in the subset, so that the user Enable a terminal to monitor HARQ information received from only base stations included in the subset. 23. The controller of claim 22 wherein the processing unit defines the subset based on at least one of uplink and downlink measurement reports. 23. The controller of claim 22 wherein the processing unit transmits information to the user terminal as to which base stations should be included in the subset. 23. The controller of claim 22 wherein the processing unit transmits information to which base stations of the packet radio system which base stations are to be included in the subset. 23. The controller of claim 22 wherein the processing unit updates the subset when new base stations to be included in the subset are detected in a soft handover active set. 23. The controller of claim 22, wherein the processing unit defines the subset based on at least one of signal-to-noise ratio measurements and other thresholds of the base stations of an active set. . 28. The system of claim 27, wherein the processing unit is configured to exclude the given base station from the subset when the signal-to-noise ratio of a given base station is lower by a predetermined amount than the signal-to-noise ratio of the strongest base station of the active set. A controller for a packet radio system, characterized in that it is defined to be. A user terminal for a packet radio system using hybrid automatic retransmission request (HARQ), A transceiver 222 in communication with a controller of the packet radio system and at least one base station; And A processing unit 226 for controlling the functions of the user terminal, Wherein the processing unit monitors HARQ information received from only the base stations included in the subset defined by the controller based on the capabilities of the base stations of the soft handover active set. terminal. 30. The user of claim 29, wherein the user terminal receives from the controller information regarding which base stations of a soft handover active set are included in the subset defined by the controller. terminal. 31. The method of claim 30, wherein upon receiving information from the controller, receive at least one additional subset update command to indicate whether base stations of an active set are included in the subset. User terminal. A packet radio system using hybrid automatic retransmission request (HARQ), A controller for controlling at least one base station of the packet radio system, wherein the controller comprises first communication means for communicating with a user terminal of the packet radio system and the at least one base station; A user terminal including second communication means for communicating with the controller US base stations of the packet radio system; And One or more base stations including third communication means for communicating with the controller and the user terminal of the packet radio system, Wherein the controller comprises defining means for defining a subset of the soft handover active set based on the capabilities of the base stations of the active set and indication means for providing information as to which base station is included in the subset. Wherein the user terminal comprises monitoring means for monitoring HARQ information received from only base stations included in the subset. A controller for a packet radio system using hybrid automatic retransmission request (HARQ), Communication means for communicating with at least one base station and user terminals of a packet radio system; And It comprises a control means for controlling the functions of the controller, Wherein the control means provides definition means for defining a subset of a soft handover active set based on capabilities of base stations in an active set, and information about which base stations are included in the subset, so that the user And indicating means for causing terminals to monitor HARQ information received from only base stations included in the subset. A user terminal for a packet radio system using hybrid automatic retransmission request (HARQ), Communication means for communicating with a controller of the packet radio system and one or more base stations; And It comprises a control means for controlling the functions of the user terminal, Wherein the control means monitors HARQ information received from only the base stations included in the subset defined by the controller based on the capabilities of the base stations of the soft handover active set. terminal.

Images