KR200379942Y1 - Apparatus for supporting an enhanced uplink soft handover operation - Google Patents

Abstract

The present invention relates to a method and apparatus for supporting enhanced uplink soft handover (EU-SHO) operation of a wireless transmit / receive unit (WTRU). The apparatus may be a multi-cell wireless communication system comprising at least two EU-SHO Node Bs and a Radio Network Controller (RNC). The RNC includes a medium access control (MAC) entity that handles enhanced uplink dedicated channel (EU-DCH) functionality. The RNC is configured according to the first architecture when the EU-SHO operation of the WTRU is not occurring, and according to the second architecture when the WTRU is operating in the EU-SHO operation. According to the second architecture, the MAC entity of the RNC includes an ACK / NACK generator for generating a signal indicating whether EU transmission from the WTRU has been successfully received by the RNC, and an uplink scheduler for scheduling the EU transmission of the WTRU. do.

Description

APAPATUS FOR SUPPORTING AN ENHANCED UPLINK SOFT HANDOVER OPERATION}

The present invention relates to a wireless communication system. More specifically, the present invention provides a method and apparatus for supporting enhanced uplink soft handover (EU-SHO) operation by reconfiguring the radio network controller (RNC) and node B architecture. It is about.

Currently, the third generation partnership project (3GPP) is working under the background of the study item "FDD Uplink Enhancement" of Release 6 (R6) 's universal mobile telecommunications system (UMTS). Methods to improve link coverage, throughput and transmission latency have been studied.

To achieve this goal, it is widely expected that Node B (base station) will assume responsibility for scheduling and assigning uplink resources (physical channels) to users. The principle is that Node B can more effectively determine and manage uplink radio resources in a shorter period of time than RNC, even if the RNC performs rough control. The downlink already has a similar method: release 5 (R5) high speed downlink packet access (HSDPA) in UMTS frequency division duplex (FDD) and time division duplex (TDD) modes. ) Was adopted.

It is also contemplated that several independent uplink transmissions can be handled between a wireless transmit / receive unit (WTRU) and a universal terrestrial radio access network (UTRAN) within a common time interval. . Examples of this include hybrid automatic repeat request (HARQ) operations in the medium access control (MAC) layer or simply automatic ARQ (ARQ) operations in the MAC layer. The number of times for requesting retransmission may vary. To limit the impact on the system architecture, the introduction of an enhanced uplink dedicated channel (EU-DCH) should not affect the protocol layer above the MAC. One requirement for this is that data must be delivered sequentially to the radio link control (RLC) protocol layer. Therefore, like HSDPA in the downlink, UTRAN reordering functionality is required to organize the received data blocks in the order generated by the WTRU RLC entities.

Soft handover macro diversity operation requires centralized control of uplink transmissions in each cell in the active set. The active set may include a plurality of Node Bs. It is retransmitted until successful transmission by at least one Node B is realized. Not all Node Bs guarantee successful transmission. Therefore, it is not possible to guarantee a completely successful transmission within any Node B, so that resequencing of successful transmissions cannot be achieved.

The present invention relates to a method and apparatus for supporting EU-SHO operation of a WTRU. The apparatus may be a multi-cell wireless communication system, an RNC or an integrated circuit (IC) located within the RNC. The multi-cell wireless communication system includes at least two EU-SHO Node Bs and an RNC. The RNC includes a first MAC entity that handles EU-DCH functionality. The RNC is configured according to the first architecture when the EU-SHO operation of the WTRU is not occurring, and according to the second architecture when the WTRU is operating in the EU-SHO operation. According to a second architecture, the first MAC entity of the RNC is configured to generate a signal indicating whether EU transmission from the WTRU has been successfully received by the RNC, and a first ACK / NACK generator to generate a signal indicating scheduling of EU transmission of the WTRU. Includes 1 uplink scheduler.

Each EU-SHO Node B includes a second MAC entity that handles EU-DCH functionality. The second MAC entity includes an HARQ / ARQ entity that communicates with the RNC over its respective signaling channel.

If the EU-SHO operation of the WTRU is not occurring, a second MAC entity in Node B that is currently operating with respect to the WTRU is sent a signal indicating whether EU transmission from the WTRU was successfully received by Node B. And a second ACK / NACK generator to send to the WTRU, and a second uplink scheduler to schedule EU transmissions of the WTRU. The first uplink scheduler may communicate with each EU-SHO Node B via the EU frame protocol.

If the WTRU is operating in EU-SHO operation, only the second MAC entity in EU-SHO Node B includes a HARQ / ARQ entity.

The invention is now described with reference to the drawings, in which like elements are designated by like reference numerals.

Hereinafter, the term "WTRU" includes, but is not limited to, user equipment (UE), mobile station, fixed or mobile subscriber unit, pager, or any kind of device operable in a wireless environment. The term "base station" also includes, but is not limited to, Node B, site controller, access point, or any kind of interfacing device in a wireless environment.

The present invention is applicable to TDD, FDD and time division synchronous code division multiple access (TD-SCDMA), as is generally applied to UMTS, CDMA 2000 and CDMA, and also to other wireless systems. Applicable In CDMA 2000, the present invention can be implemented in EV-DO (ie, data only) and EV-DV (ie, data and voice).

Features of the present invention may be integrated into the IC, or may consist of circuitry that includes a plurality of interconnected components.

The present invention, in one embodiment, provides a distributed UTRAN MAC architecture solution for enhanced uplink incorporating a reordering function, an uplink scheduling function, an ACK / NACK generation function, and an HARQ / ARQ entity. Appropriate use of the UTRAN MAC architecture can efficiently support soft and hard handover, reducing MAC data loss and RLC recovery. The present invention proposes details of the preferred MAC architecture for addressing these requirements.

In addition, the present invention proposes a distributed UTRAN MAC architecture for enhanced uplink. The present invention also proposes to implement a HARQ / ARQ entity at Node B and to implement a reordering function in the RNC regardless of the WTRU operating scenario.

In addition, the present invention proposes to implement the uplink scheduling function in the Node B and RNC. However, in the case of a WTRU, only one uplink scheduling function is configured at any time. Whether the uplink scheduling function is configured in Node B or RNC depends on the WTRU operating scenario (with or without soft handover).

It is important to note that the present invention also proposes to implement the ACK / NACK generation function at the Node B and RNC. However, in the case of a WTRU, only one ACK / NACK generation function is configured at any time. Whether the ACK / NACK generation function is configured in Node B or RNC depends on the WTRU operation scenario (whether soft handover or not).

During EU-SHO operation, the upper layer maintains an active subset of EU-DCH EU cells, and the EU-DCH remains in soft handover macro diversity state. The cells in these active subsets are controlled by different EU-SHO Node Bs.

According to the present invention, the architecture of a multi-cell wireless communication system is changed to either the first configuration or the second configuration according to whether EU-SHO operation occurs.

1 is a diagram illustrating a first system configuration 100 of a wireless communication system including an RNC 105 and a Node B 110 during normal operation (not a soft handover operation). Node B communicates with WTRU 115. The RNC 105 is configured to include the first MAC entity 120. The first MAC entity 120 in the RNC 105 handles the EU-DCH functionality and includes one or more reordering functionality entities 125. Each reordering functional entity 125 is in communication with a higher protocol layer 130 in the RNC 105 and includes an associated data buffer (not shown). Node B 110 is configured to include a second MAC entity 135, the second MAC entity 135 handling the EU-DCH functionality and having an HARQ / ARQ entity 140 with an ACK / NACK generator 145. ) And uplink scheduler 150.

HARQ / ARQ entity 140 is configured in Node B 110 to handle HARQ / ARQ functionality for either user. The reordering functional entity 125 is configured in the RNC 105 to perform sequencing on the correctly received data block, that is, the packet data unit (PDU), thereby sequencing to the higher protocol layer 130. Support delivery. Uplink scheduler 150 is configured in Node B 110 to schedule EU transmissions of WTRU 115. The ACK / NACK generator 145 is configured in the Node B 110 to inform the WTRU 115 whether the EU transmission was successful. As shown in FIG. 1, the ACK / NACK generator 145 is integrated into the HARQ / ARQ entity 140 of the Node B 110 in a normal operation scenario.

The reordering functional entity 125 is not affected by internal Node B EU serving cell changes, ie hard handover. In other words, the RNC's reordering buffer (not shown) does not need to be flushed during internal Node B EU serving cell changes. Since the reordering buffer is not flushed, it is not delivered out of order to the RLC due to internal Node B EU serving cell changes and there is no RLC recovery (WTRU side). The ACK / NACK and uplink scheduling information is sent to the WTRU 115 via fast layer one signaling.

FIG. 2 is a diagram illustrating a second system configuration 200 of the wireless communication system shown in FIG. 1. When the RNC 105 detects that the WTRU 115 changes from a normal operation to an EU-SHO operation, a change from the first system configuration 100 to the second system configuration 200 occurs. The second system configuration 200 includes an RNC 205 and at least two EU-SHO Node B 210 (210A ... 210N) operating during EU-SHO. The RNC 205 is configured to include a first MAC entity 215 located at the RNC 205. The first MAC entity 215 handles EU-DCH functionality and includes one or more reordering functionality entities 220, an ACK / NACK generator 225 and an uplink scheduler 230. Each reordering functional entity 220 communicates with a higher protocol layer 235 in the RNC 205 and includes an associated data buffer (not shown). Each Node B 210 is configured to include a second MAC entity 240 (240A ... 240N), the second MAC entity 240A ... 240N handles EU-DCH functionality, and a HARQ / ARQ entity. (245) (245A ... 245N). Each HARQ / ARQ entity 245 handles HARQ / ARQ functionality for either user. The uplink scheduler 230 in the first MAC entity 215 located in the RNC 205 communicates with each Node B 210 via the EU frame protocol 250A ... 250N. HARQ / ARQ entities 245A ... 245N communicate with RNC 205 via signaling channels 255A ... 255N, respectively.

2, during the EU-SHO operation, if a data block received at an EU-SHO Node B 210 is successfully decoded, that is, the data block passes a cyclic redundancy check (CRC). Is transmitted to the RNC 205 via EU frame protocol (255A ... 255N). Reordering functional entity 220 in RNC 205 supports sequential delivery to higher protocol layer 235 by performing reordering on correctly received data blocks. The uplink scheduler 230 in the RNC 205 schedules EU transmissions of WTRUs in the cell controlled by different EU-SHO Node B 210. The ACK / NACK generator 225 in the RNC 205 sends to the WTRU if the RNC 205 received at least one copy of a successfully decoded data block that received a good CRC result from the EU-SHO Node B 210. Generate a positive acknowledgment (ACK) to send. Otherwise, it determines that the data block has not been received correctly, and the ACK / NACK generator 225 in the RNC 205 generates a negative acknowledgment (NACK) to send to the WTRU.

Data blocks received from different EU-SHO Node B 210 may be combined and organized to be sequentially delivered to higher protocol layer 235. The reordering functional entity 220 located within the RNC 205 may process the EU MAC PDUs to be successfully received and delivered appropriately to the higher protocol layer 235 regardless of the Node B that provided each received PDU. Thus, loss of MAC data and RLC recovery are reduced.

By using the uplink scheduler 230 in the RNC 205 during EU-SHO operation, EU transmissions scheduled by one EU-SHO Node B 210 are controlled by another EU-SHO Node B 210. It is acceptable in terms of resources and interference of the cell.

3 is a flow diagram of a process 300 including method steps for implementing the system configuration 100, 200 shown in FIGS. 1 and 2, respectively. During normal operation, the RNC 105 continues to monitor any indication that the EU soft handover operation is about to begin (step 305). As shown in the system configuration 100 of FIG. 1, during normal operation, i.e., before and after the EU-SHO operation, the current Node B 110 of the WTRU 115 is connected to the ACK / NACK generator 145 and uplink. It is configured to include a scheduler 150 (step 310). If in step 305 the RNC 105 detects any indication that the EU-SHO operation is about to be initiated, the architecture of the MAC entity 120 in the RNC 105 of FIG. 1 may cause the MAC entity 215 in the RNC 205 of FIG. By reconstructing according to the architecture of the C, the MAC entity 215 includes the ACK / NACK generator 225 and the uplink scheduler 230 (step 315). As determined in step 320, after the soft handover operation is completed, the ACK / NACK generator 225 and the uplink scheduler 230 in the MAC entity 215 of the RNC 205 are disassembled and shown in FIG. As shown, a new Node B 110 associated with the WTRU 115 during the EU-SHO operation is configured to include an ACK / NACK generator 145 and an uplink scheduler 150 (step 310).

While the present invention has been shown and described in connection with particularly preferred embodiments, it will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the scope of the present invention.

According to the present invention, a method and apparatus for supporting enhanced uplink soft handover (EU-SHO) operation by reconfiguring the architecture of a radio network controller (RNC) and a Node B can be provided.

1 is a diagram showing a first system configuration during normal operation (not a soft handover operation) according to the present invention.

2 illustrates a second system configuration when the WTRU is operating in EU-SHO operation in accordance with the present invention.

3 is a flow diagram of a process including method steps for implementing the system configuration of FIGS. 1 and 2.

<Explanation of symbols for the main parts of the drawings>

110: node B

120: first MAC entity

125: reorder function entity

130: upper protocol layer

135: second MAC entity

140: HARQ / ARQ entity

145: ACK / NACK Generator

150: uplink scheduler

210: EU soft handover node B

210A, 210N: Node B 1, Node B N

215: first MAC entity

220: reorder function entity

225: ACK / NACK Generator

230: uplink scheduler

235: upper protocol layer

240A, 240N: second MAC entity

245A, 245N: HARQ / ARQ entity

Claims (11)

A multi-cell wireless communication system supporting enhanced uplink soft handover (EU-SHO) operation of a wireless transmit / receive unit (WTRU), (a) at least two enhanced uplink soft handover (EU-SHO) Node Bs, (b) a radio network controller (RNC) including a first medium access control (MAC) entity that handles enhanced uplink dedicated channel (EU-DCH) functionality; The first MAC entity, (i) a first generator for generating a signal indicating whether EU transmission from the WTRU has been successfully received by the RNC; (ii) a first uplink scheduler for scheduling EU transmissions of the WTRU, The first MAC entity is activated when the RNC begins to detect EU-SHO operation for the WTRU. delete The method of claim 1, Each EU-SHO Node B includes a second MAC entity that handles EU-DCH functionality, The second MAC entity, (iii) a second generator for transmitting a signal for the WTRU indicating whether EU transmission from the WTRU was successfully received by the Node B; (iv) a second uplink scheduler for scheduling EU transmissions for the WTRU, And if the soft handover operation does not occur for the WTRU, the second MAC entity is activated. The method of claim 3, wherein And the second MAC entity comprises a hybrid auto repeat request / auto repeat request (HARQ / ARQ) entity in communication with the RNC via a respective signaling channel. The method of claim 1, And the first uplink scheduler communicates with each EU-SHO Node B via an EU frame protocol. In a multi-cell wireless communication system comprising a radio network controller (RNC), a wireless transmit / receive unit (WTRU) and at least two enhanced uplink soft handover (EU-SHO) Node Bs in communication with the RNC, The RNC includes a medium access control (MAC) entity in communication with a higher protocol layer and handling enhanced uplink dedicated channel (EU-DCH) functionality, wherein the MAC entity is an enhanced uplink dedicated channel (EU-DCH). Cover functions, The MAC entity, (a) a generator for generating a signal indicating whether EU transmissions from the WTRU have been successfully received by the RNC; (b) an uplink scheduler for scheduling EU transmissions for the WTRU, When the RNC begins to detect EU-SHO operation for the WTRU, the MAC entity is activated. delete The method of claim 6, The uplink scheduler is in communication with each EU-SHO Node B via an EU frame protocol. A radio network controller (RNC) including at least one integrated circuit (IC), a wireless transmit / receive unit (WTRU) and at least two enhanced uplink soft handover (EU-SHO) Node Bs in communication with the RNC. In a multi-cell wireless communication system, The IC comprises a medium access control (MAC) entity in communication with a higher protocol layer, The MAC entity, (a) a generator for generating a signal indicating whether EU transmission from the WTRU has been successfully received by the RNC; (b) an uplink scheduler for scheduling EU transmissions of the WTRU, And when the RNC starts to detect EU-SHO operation for the WTRU, the MAC entity is activated. delete The method of claim 10, The uplink scheduler is in communication with each EU-SHO Node B via an EU frame protocol.