HK1125761B - Method and apparatus for forwarding non-consecutive data blocks in enhanced uplink transmissions - Google Patents

Description

Method and apparatus for delivering non-consecutive data blocks in enhanced uplink transmissions

Technical Field

The present invention relates to a wireless communication system including a wireless transmit/receive unit (WTRU), at least one node-B, and a Radio Network Controller (RNC). More particularly, the present invention relates to a method and system for delivering non-consecutive data blocks in eu transmission.

Background

In the R6 version of the third generation partnership project, methods for improving Uplink (UL) flooding, throughput, and transmission latency have been investigated. To successfully perform these methods, the scheduling and allocation of uplink physical resources has been moved from the rnc to the node-B, so that the node-B can make decisions and manage uplink radio resources on a short-term basis more efficiently than the rnc, even though the rnc retains control over the node-B.

One or more independent uplink transmissions are processed on an enhanced dedicated channel (E-DCH) between a WTRU and a Universal Mobile Telecommunications Service (UMTS) terrestrial radio access network (UTRAN) in a common time interval. A Medium Access Control (MAC) layer hybrid automatic repeat request (H-ARQ), or a simple MAC layer automatic repeat request (ARQ) operation paradigm, each respective transmission may require a different number of retransmissions for successful reception by the umts utran. This operation may form a transmission sequence loss at the mac layer.

For proper operation, the Radio Link Control (RLC) layer requires an in-sequence data transfer. A reordering function is required to identify the sequence of received data blocks generated by the wtru radio link control entity. In the prior art, a data delivery timer (referred to as the T1 timer in hsdpa) has been used to deliver non-consecutive data blocks to higher layers. The timer is started when a data block that has been correctly received cannot be delivered to the higher layer due to discontinuous reception. When the timer expires, all data blocks in the reorder buffer that are busy with the next discontinuously received data block are delivered to higher layers.

Even in normal operation, the duration for the data delivery timer is difficult to set properly because cell congestion occasionally results in relatively long periods between transmissions. Furthermore, because the radio link controls Authentication Mode (AM) out of sequence delivery, unnecessary retransmissions may result, and the setting of the data delivery timer must account for the worst case delay for proper operation. Since transmission errors are inevitable, this timer mechanism results in increased and potentially unacceptable radio link control retransmission procedures.

In order to maintain quality of service (QoS), the transmission should not be unnecessarily delayed in the delivery of the sequence provided. The timer mechanism does not provide adequate quality of service. If the duration of the timer is too short, an incorrect sensing of out-of-order transmission may result in unnecessary requests for the channel for radio link control retransmission procedures or potential releases when only a particular transmission is delayed. If the timer is too long in duration, detection and recovery of failed transmissions is delayed, making it more difficult to achieve a transmission latency qos requirement. Determining the duration of the out-of-order transmission delivery timer is more complicated in retransmission scheduling which varies relatively widely.

Disclosure of Invention

The present invention relates to a method and apparatus for delivering non-consecutive data blocks in enhanced uplink transmissions. A WTRU and one or more node-Bs including one or more ARQ/HARQ processes for supporting enhanced uplink transmissions. The data blocks transmitted by the wtru are reordered in a reordering entity located in the node-B or rnc. Upon identifying the missing data block, a data delivery timer in the node-B or rnc is started and monitors subsequent wtru transmissions to determine whether the missing data block has been discarded by the wtru. Based on the discard identification of the missing data block, the non-consecutive data blocks are delivered to a higher layer.

In an absolute priority structure, a higher priority data block is always processed before a lower priority data block, and a data block with the earliest tsn value is processed first in the same high priority data block. In such a mechanism, if at the node B, all available and active hybrid automatic repeat request processes for the wtru have successfully received: 1) a new transmission having the same priority and a higher tsn than the missing data block; or 2) one of the new transmissions having a lower priority than the missing data block, the node-B recognizes that the WTRU has discarded the missing data block.

Drawings

A more particular understanding of the present invention will be afforded to a preferred embodiment thereof as illustrated by the following examples taken in conjunction with the accompanying drawings, in which:

fig. 1A is a block diagram of a wireless communication system including one or more node bs with data reordering entities, in accordance with an embodiment of the present invention;

fig. 1B is a block diagram of a wireless communication system including a rnc with a data reordering entity, in accordance with an embodiment of the present invention;

FIG. 2 is a flow chart of a process for delivering non-contiguous data blocks using the system of one of FIGS. 1A and 1B; and

FIG. 3 is a flow chart of a process for delivering non-contiguous data blocks using the system of FIG. 1B.

Detailed Description

The term wtru hereinafter includes, but is not limited to, a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. The term node-B hereinafter includes, but is not limited to, a base station, a location controller, an access point, or any other form of interfacing device operable in a wireless environment.

The features of the present invention may be incorporated into an Integrated Circuit (IC) or be configured in a circuit comprising a plurality of interconnected components.

Fig. 1A is a block diagram of a wireless communication system 100 including one or more node bs with data reordering entities 122, in accordance with an embodiment of the present invention. The system 100 includes a wtru 102, one or more node-bs 104, and a radio network controller 106. The wtru 102 transmits the enhanced dedicated channel data by assigning an enhanced dedicated channel 142. The node-B104 transmits an authentication message or an unauthenticated message based on the success or failure of decoding the data at the node-B104, as indicated by arq/h arq processes 112 and 128 in the wtru 102 and node-B104, respectively, using a harq or simple arq operation via the Downlink (DL) eu signaling channel 144.

Referring to fig. 1A, each of the wtru 102, the node-B104 and the rnc 106 includes a new mac entity 110, 120, 130, respectively, for ul transmissions. The mac entity 120 of the node B104 includes a reordering entity 122, a data reordering buffer 124, and a data delivery timer 126, respectively, for communicating in the sequence of data blocks. Data transmitted by the wtru 102 over the enhanced dedicated channel 142 is reordered by the reordering entity 122 before being delivered to a higher layer. The re-ordering entity 122 receives data blocks (mac standard Protocol Data Units (PDUs)) and delivers the PDUs to a higher layer in consecutive transmission sequence values. Non-consecutive mac-std pdus (i.e., causing a missing data block) are not delivered to the higher layer until the data delivery timer 126 expires. The re-ordering entity 122 uses the knowledge of the arq/h-arq process 128 to determine whether the missing data block is discarded by the wtru 102 and delivers non-consecutive data blocks to higher layers.

Fig. 1B is a block diagram of a wireless communication system 150 including a rnc with data reordering entity 132 operation, in accordance with one embodiment of the present invention. The system is the same as the system 100 of fig. 1A, and includes a wtru 102, one or more node-bs 104, and a radio network controller 106. However, instead of the node B104 including a reordering entity 122, the mac entity 130 of the rnc 106 includes a reordering entity 132, a reordering buffer 134 and a data delivery timer 136, respectively, for in-sequence delivery of the data blocks. Data transmitted by the wtru 102 over the enhanced dedicated channel 142 is reordered by the reordering entity 132 before being delivered to a higher layer. The re-ordering entity 132 receives data blocks (mac standard Protocol Data Units (PDUs)) via the node B104 and delivers the PDUs to a higher layer in consecutive transmission sequence numbers. Non-consecutive mac-std pdus (i.e., causing a missing data block) are not delivered to the higher layer until the data delivery timer 136 expires. The re-ordering entity 132 uses the knowledge of the arq/h-arq process 128 in the node-B104 to determine whether the missing data block is discarded by the wtru 102 and to deliver non-consecutive data blocks to higher layers.

The h-arq process dispatch mechanism is preferably based on the absolute priority of the data block. After identifying that a data block of a specific tsn is missing in the ordering buffer of the utran (i.e., a node B or a rnc), if for the wtru, all subsequent missing data block detections of arq/h-arq processes available and active in the node B have: 1) initiating a new transmission for transmissions of the same priority class having a higher sequence number; or 2) to initiate one of the new transmissions in order to have a lower priority level transmission, the re-ordering entity 122, 132 determines that the missing data block is missing. In such a case, the re-ordering entity 122, 132 determines that the missing data block is missing at the Medium Access Control (MAC) layer and delivers the non-consecutive data blocks to a higher layer.

FIG. 2 is a flow chart of a process 200 for delivering non-consecutive data blocks, consistent with an embodiment of the present invention. The process 200 may be performed using one of the system 100 of FIG. 1A or the system 150 configuration of FIG. 1B. The node B104 maintains a limited number of arq/h-arq processes 128 for each wtru 102. The re-ordering entity 132 in the rnc 106 may not have knowledge of the h-arq process 128 in the wtru 102 and the node-B104. Thus, when using the system 150 configuration shown in fig. 1B, the node-B104 provides the required information to the rnc 106 for the re-ordering entity 132 to determine whether the wtru 102 has discarded the missing data block.

The data blocks received and correctly decoded by the node B104 or the rnc 106 from the wtru 102 are reordered in a reordering buffer 124 for the node B104 or the reordering buffer 134 for the rnc 106. When using the configuration of the system 150, the node-B104 delivers the successfully decoded data block to the rnc 106 along with the h-arq process number and/or the frame value when the transmission was received. The frame number value may be the frame at which the new data pointer was received or the frame at which the successful transmission was made.

The re-ordering entity 122 of the node-B104 or the re-ordering entity 132 of the rnc 106 identifies a missing data block using the tsn (step 202). A unique transmit sequence value is assigned to each data block by the wtru 102. Based on the identification of the missing data block, the node-B104 starts the data delivery timer 126 or the rnc 106 starts the data delivery timer 136 (step 204). The re-ordering entity 122 or 132 determines whether the data delivery timer 126 or 136, respectively, has expired (step 206). If the timer 126 or 136 has expired, the re-ordering entity 122 or 132 delivers non-consecutive data blocks to higher layers (step 210) and initiates a higher layer data recovery step.

If the timer 126 or 136 has not expired, the re-ordering entity 122 or 132 further determines whether the missing data block is discarded by the wtru 102 based on a known arq process assignment scheme at the wtru 102 (step 208). When the rnc 106 determines to discard data blocks in step 208, the number of frames implicitly transmitted from the received transmission is determined for the h-arq. Thereafter, when the wtru 102 discards the particular transmission, the node-B104 or the rnc 106 may determine an out-of-order reception based on subsequent assignment rules for h-arq process assignment and h-arq process.

The h-arq process assignment mechanism at the wtru 102 is preferably based on the absolute priority of the data block, although other mechanisms may be used. In an absolute priority structure, a higher priority data block is always processed before a lower priority data block, and a data block with the earliest tsn value is processed first in the same high priority data block. In such a mechanism, if at the node B104, there has been successful reception for all available and active arq/h arq processes 128 of the wtru 102: 1) a new transmission having the same priority and a higher tsn than the missing data block; or 2) one of the new transmissions having a lower priority than the missing data block, the node-B104 or the rnc 106 recognizes that the wtru 102 has discarded the missing data block.

Alternatively, if the hybrid automatic repeat request process associated with the missing data has been successfully received: 1) a new transmission having the same priority and a higher tsn than the missing data block; or 2) one of the new transmissions having a lower priority than the missing data block, the node-B104 or the rnc 106 recognizes that the wtru 102 has discarded the missing data block. The hybrid automatic repeat request processing is known from the time of transmission/reception. The time may be specified as a frame or a sub-frame value.

If either condition is met, the node-B104 or rnc 106 determines that the missing data block has been discarded by the wtru 102 at the mac layer. Then, the re-ordering entity 122 or 132 waits for the expiration of the data delivery timer 126 or 136 to deliver non-consecutive data blocks to higher layers. If neither case is met, the node-B104 or rnc 106 determines that the missing data block has not been discarded, the process 200 proceeds to step 212 to wait for the next Transmission Time Interval (TTI) or data block, and the process 200 then returns to step 206.

Upon receiving a new data pointer, the node B104 performs a new transmission. The new data pointer is used to indicate whether a transmission is new or old (re-transmission). For old data, some combining may be performed at the node B104. A new data pointer may also be represented by a hybrid automatic repeat request processing transmission counter. When the h-arq process transmission is set to an initial value, this indicates the new data pointer. The new transmission may also be determined by receiving transmission queue Identities (IDs) and the transmitted sequence values from the subsequent decoding.

The node-B104 may support a plurality of reordering queues for each wtru 102 and the out-of-sequence detection and delivery logic may operate separately for each reordering queue.

In another embodiment, the h-arq process assignment mechanism at the wtru 102 is associated with the missing data block. In an absolute priority structure, a higher priority data block is always processed before a lower priority data block, and a data block with the earliest tsn value is processed first in the same high priority data block. In such a mechanism, if at the node B104, there has been successful reception for all available and active arq/h arq processes 128 of the wtru 102: 1) a new transmission having the same priority and a higher tsn than the missing data block; or 2) one of the new transmissions having a lower priority than the missing data block, the node-B104 recognizes that the wtru 102 has discarded the missing data block.

If either condition is met, the node-B104 determines that the missing data block has been discarded by the wtru 102 at the mac layer and then the re-ordering entity 122 delivers non-consecutive data blocks to higher layers without waiting for the expiration of the data delivery timer 126. If neither case is met, the node-B104 determines that the missing data block has not been discarded and the process 200 proceeds to step 212 to wait for the next tti in the case of the node-B104 or the next data block in the case of the rnc 106. The process 200 returns to step 206 after the next tti occurs or the next data block is received.

Upon receiving a new data pointer, the node B104 performs a new transmission. The use of the new data pointer may also incorporate hybrid automatic repeat request tracking in the node B104. The new transmission may also be determined by receiving the transmit queue Identities (IDs) and the subsequently decoded tsn.

FIG. 3 is a flow chart of a process 300 for delivering non-consecutive data blocks in accordance with a third embodiment of the present invention. In this embodiment, the rnc 106 notifies the node-B104 of a missing data block, and the node-B104 detects whether the wtru 102 has discarded the missing data block and reports it to the rnc 106.

A reordering entity 132 in the rnc 106 checks whether there is a missing data block in the reordering buffer 134 (step 302). If there are no missing data blocks, the process 300 proceeds to step 312 to wait for the next received data block. If there is a missing data block, the re-ordering entity 132 starts a data delivery timer 136 and sends a "start monitor" command to the node B104 (step 304). When the out-of-order data block in the reorder buffer 134 is identified, the frame count reported by the node B104, and the ghost-complete-sequence value of the missing data block, are also included in the "start watch" command.

After receiving the start monitor command from the rnc 106, the node-B104 checks its current database to check all data blocks after the frame number indicated by the rnc 106 and monitors subsequent transmissions to determine whether the wtru 102 has discarded the missing data block based on the known h-arq process non-dispatch mechanism at the wtru 102 (step 306). As described above, the arq/h-arq processes 112 are preferably assigned according to an absolute priority structure. In such a case, the node B104 determines whether there is any arq/h-arq process 128 available and active in the node B104 for the wtru 102: 1) a new transmission having the same priority and a higher tsn than the missing data block; or 2) a new transmission having a lower priority than the missing data block.

If either is true, the node-B104 sends a transmission failure message to a re-ordering entity 132 in the rnc 106 via the e-dch frame standard protocol (step 308). The transmission failure information also includes the priority indicating the reordering queue body and the sequence value of the data block. The node B104 then stops monitoring for this event. If neither case is met, the process 300 proceeds to step 312 to wait for the next received data block.

Based on receiving the transmission failure message, the reordering function in the rnc 106 delivers the non-consecutive data blocks to higher layers before the timer expires (step 310).

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention.

While the invention has been described in terms of preferred embodiments, other variations upon the inventive concepts will be apparent to those skilled in the art from the following claims.

Claims (2)

1. A wireless communication method performed in a wireless communication system for forwarding non-consecutive data blocks that have not been previously forwarded due to a missing data block, the wireless communication system including a wtru, a node-B and a rnc, the method comprising:

reordering the data blocks by the wtru according to the specific tsn values assigned to each data block, wherein the wtru and node-B include one or more arq/h-arq processes for supporting transmission and reception of data blocks over an enhanced dedicated channel;

the rnc receiving a data transmission comprising a plurality of data blocks;

the RNC identifying a missing data block in the plurality of data blocks;

the RNC starting a timer for delivering non-consecutive data blocks;

the rnc transmitting a start monitor command to the node-B, wherein the node-B monitors transmissions of subsequent wtrus to determine whether the missing data block has been discarded by the wtru;

the rnc receiving a transmission failure message from the node-B indicating that the missing data block is discarded; and

upon receiving the transmission failure message, the rnc forwards the non-consecutive data blocks to a higher layer before the timer expires.

2. The method of claim 1 wherein the start watch command includes a number of frames, a priority, and a sequence number of the missing data blocks.