Medium access control layer architecture for supporting enhanced uplink

The present invention relates to a wireless communication system comprising a wireless transceiver (WTRU) and a Node-B node. In particular, the invention relates to an architecture of a medium access control (MAC) layer and functionality for supporting an improved uplink (EU) in a wireless communication system.

BACKGROUND [0002] Methods for improving coverage, bandwidth, and uplink transmission delay (UL) are considered in Release 6 of the Third Generation Partnership Project (3GPP). In order to successfully implement these methods, the scheduling and assignment of the UL link physical resources has been transferred from the radio network controller (RNC) to the Node-B node, so that the Node-B node can make decisions and manage the UL radio resources in the short term more efficiently than the controller RNC, even if the RNC controller retains overall control over the Node-B node.

[0003] One or more independent UL links are processed in an enhanced dedicated channel (E-DCH) between the WTRU and the UMTS of the universal mobile telecommunications system (UMTS) within a common time interval. . One example of this is the hybrid MAC automatic layer request (H-ARQ) or normal MAC layer ARQ operation in which an individual transmission may require a different number

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This means that it can be successfully received by the network

UTRAN.

[0004] Several documents have been developed in 3GPP that provide general information about the technological principles of the invention. For example, the 3GPP TR report 25.896, V2.0.0 (March 2004), includes a feasibility study by computer simulations of a streamlined uplink for a UMTS terrestrial radio frequency division duplex (UMTS Terrestrial Radio Access Frequency-Division

Duplex). The "E-DCH L2 / L3 issues, MAC multiplexing report (R2-040470)", 3GPP TSG-RAN WG2 # 41 (February 16, 2004) also contains background information that is relevant to the understanding of the present invention.

SUMMARY OF THE INVENTION [0005] The present invention relates to an improved MAC layer architecture and functionality for supporting an EU link according to the independent claims. The new MAC unit for the EU link referred to as the MAC-e entity is defined and entered in the WTRU, Node-B and RNC. The WTRU MAC-e unit supports H-ARQ transmissions and retransmissions, performs priority handling, supports MAC-e multiplexing and selects a combination of transport formats (TFCs). The Node-B node's MAC-e supports H-ARQ transmissions and retransmissions, improved dedicated channel (E-DCH) scheduling and MAC-e demultiplexing. The RNC's MAC-e unit provides in-sequence delivery and supports data connection from different Node-B nodes.

[0006] The MAC-e entity of the WTRU comprises an EU speed request / assignment unit, a priority serving unit, a TFC combination selection entity, and an H-ARQ entity. Speed ​​request / assign unit

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The UE sends a rate request to the Node-B for transmitting data via the E-DCH and for processing the grant grant received from the Node-B. The priority service unit manages the data assignment and the H-ARQ process according to the priority of the data to be transmitted. The TFC combination selection unit selects the TFC data combination. The H-ARQ unit retransmits the data according to the transmission feedback from the Node-B node. The MAC-e entity of the Node-B node comprises a scheduler, a demultiplexer and an H-ARQ unit.

BRIEF DESCRIPTION OF THE DRAWINGS [0007] A more detailed understanding of the invention may take place on the basis of the following description of preferred embodiments, given as an example, and which may be understood in connection with the accompanying drawing in which:

Figure 1 is a block diagram of a wireless communication system in accordance with the present invention;

Figure 2 is a block diagram of the protocol architecture of the WTRU according to the present invention;

Figure 3 is a block diagram of the MAC-e architecture in a WTRU according to the present invention;

Figure 4 is a block diagram of the MAC-e architecture at a Node-B node in accordance with the present invention; and Figure 5 is a block diagram of the MAC-e architecture of the WTRU and the Node-B node together with the signaling process between the WTRU and the Node-B in accordance with the present invention.

DETAILED DESCRIPTION OF PREVIOUS EXEMPLARY EMBODIMENTS

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[0008] Hereinafter, the term "WTRU" includes a user equipment, a mobile station, a fixed or mobile subscriber unit, a pager or any other type of device capable of operating in a wireless environment, but is not limited to devices. In further references, the name & quot; Node-B & quot; includes a base station, a site controller, an access point or any other type of interface device in a wireless environment, but is not limited to said devices.

[0009] The features of the present invention may be included in an integrated circuit (IC) or may be configured in a system comprising a large number of interconnected components.

[0010] Figure 1 is a block diagram of a wireless communication system 10 in accordance with the present invention. The system 10 includes a WTRU 100, a Node-B 200 node and an RNC 300 controller. The RNC 300 controller controls the entire operation of the EU link by configuring the EU link parameters for the Node-B 200 and the WTRU 100, such as the initial transmit power level, the maximum allowed EU transmit power or available channel resources per node Node-B. Between the WTRU 100 and the Node-B node 200, an E-DCH 102 is established to support the transmission of the EU link.

[0011] For transmission of the E-DCH channel, the WTRU 100 sends a speed request to the Node-B node via the UL EU signal channel 104. In response, the Node-B 200 sends a speed grant to the WTRU 100 via the downlink (DL) UE signaling channel 106. After allocation of the EU radio resources to the WTRU 100, the WTRU 100 transmits the E-DCH data via the E-DCH 102 channel. In response to E-DCH channel transmissions, the Node-B sends a confirmation (ACK) or negative acknowledgment ( NACK) for H-ARQ operations via DL UE signaling channel 106. Node-B 200

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EP 2 276 301 B1 may also correspond to speed assignments to the WTRU 100 in response to E-DCH data transmissions. [0012] Figure 2 is a block diagram of the channel protocol architecture E-DCH 102 in accordance with the present invention. The new MAC entity for the EU link referred to as MAC-e is formed in the WTRU 100, the Node-B 200 and the RNC 300 to support all functions related to the transmission and reception of the E-DCH. The MAC-e entity is inserted in the WTRU 100 unit between the MAC-d 130 unit and the physical layer unit 110 (PHY). MAC-e 120 in the WTRU unit supports H-ARQ transmissions and retransmissions, performs priority handling, supports MAC multiplexing and selects TFC combinations. A MAC-e 220 unit is implemented in the Node-B 200 node that supports H-ARQ transmissions and retransmissions, E-DCH channel planning and MAC demultiplexing. A MAC-e 320 unit is inserted in the RNC 300 to provide sequence delivery and to handle data connection from different Node-B nodes.

[0013] Figure 3 is a block diagram of the architecture of the MAC-e unit 120 in the WTRU 100 in accordance with the present invention. The MAC-e entity 120 of the WTRU comprises an EU speed request / uplink unit 122, a priority service unit 124, a TFC combination selection unit 126, and an H-ARQ 128 unit. It should be noted that FIG. 3 is provided as an example of a preferred embodiment of the present invention and that the units shown in Figure 3 may be incorporated into a common functional unit MAC and that the functions may be implemented by a larger or smaller number of functional units.

[0014] The link speed request / assignment unit 122

The EU is responsible for requesting radio resources from the node

Node-B 200, when the WTRU 100 has E-DCH channel data waiting to be transmitted via the E-DCH channel

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Emitted to signaling

102. The UE link speed request could be one of magnitude: traffic flow rate, desired data rate, TFC combination index, and traffic flow measurement (TVM) for each data stream. The speed request may be a Node-B node via either physical or MAC layer signaling.

Speed ​​requests are generated based on TVM measurement of radio link control (RLC) data. TVM measurement may include data traffic intensity for E-DCH transmission or optionally may further include data waiting for retransmission with active H-ARQ processes.

[0015] When velocities (i.e. Node-B 200, unit

WTRU

100 receives the allocation of speed and / or time planning), from the unit nodes

The WTRU may receive a speed grant from more than one Node-B), the UE speed request / ratio entity 122 notifies the priority handler 124 that resources are available for data transmission. The received speed assignments specify the subset of the E-DCH transport combination combination of transport formats (TFCS), and / or the start time, and duration (optional).

[0016] By sending a speed request, the WTRU 100 may request the Node-B 200 to change the set of acceptable UL combination TFCs in the TFCS set, and the Node-B 200 may change the set of allowed UL combination TFCs in the TFCS by sending granting speed. The WTRU 100 may send an update of the scheduling information to the Node-B 200 to provide buffer occupancy and / or available transmit power information, such that the scheduler 222 at the Node-B node 200 may determine an appropriate TFCS indicator and a transmission time interval. For fast planning by continuous control, the Node-B 200 can send parameters that represent available interference, what system can tolerate, and thus

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In addition, the specified sequential number prevents additional interference by WTRUs in the speed control mode. One way to accomplish this is to signal the Node-B node 200 of the allowable transmit power that the WTRU 100 may use for the transmission of the EU link in speed allocation.

[0017] The priority serving entity 124 manages the allocation of data streams and H-ARQ processes according to the priority of the data. Based on the feedback information from the transmission of the associated DL UE signaling, either a new transmission or retransmission is determined.

is the transmission sequence number identification (ID) and transmission sequence number (TSN) for each MAC protocol data layer (PDU). The TSN number is unique for each priority class in the E-DCH channel, and is incremented for each new data block. Optionally, the priority serving unit 124 may pause the retransmission of the low priority data. New data transmission with a higher priority may be initiated instead of an ongoing retransmission of the low priority data at any time to support prioritization.

[0018] The TFC combination selection unit 126 selects a TFC combination for data to be transmitted on the E-DCH 102 according to information signaled in the speed grant, and multiplexes multiple MAC-d flows into one MAC-e PDU. Granting speed can either be an absolute grant or a relative grant. The absolute grant provides an absolute limit to the maximum amount of UL link resources that the WTRU may use. The relative grant increases or decreases the resource constraint compared to the previously used value.

[0019] The selection of the TFC combination is dependent on the maximum allowable transmit power and the respective subset

TFCS allowed by the speed grant from the Node-B node

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200. The selection of the TFC combination is based on the priorities of the logical channels, so that the selection of the TFC combination maximizes the transmission of data with a higher priority. Permissible combinations of MAC-d flows in one MAC-e PDU, which is configured by the RNC, are also included in the selection of the TFC combination.

[0020] The H-ARQ 128 unit handles all the tasks that are required for the H-ARQ protocols. The H-ARQ 128 unit is responsible for storing the MAC-e content and retransmitting it in case of unsuccessful transmission. The H-ARQ 128 unit can support multiple instances, (H-ARQ processes), H-ARQ protocol. There may be more than one H-ARQ process for the EU link configured in the WTRU 100.

[0021] In accordance with the present invention, synchronous H-ARQ is preferably implemented. Thus, the operation of H-ARQ is based on synchronous ACK and NACK DL link confirmation and synchronous retransmissions on the UL link.

[0022] Figure 4 is a block diagram of the architecture of the MAC-e 220 unit at the Node-B node 200 in accordance with the present invention. The MAC-e entity 220 of the Node-B includes a scheduling unit 222, a demultiplexer 224 and an H-ARQ 226. In the Node-B node, one MAC-e 220 is preferably provided for each WTRU and one scheduler is preferably provided for every cell. The scheduler 222 manages the E-DCH channel cell resources between the WTRUs.

[0023] The scheduler 222 manages E-DCH resource resources between WTRUs and H-ARQ processes. Based on speed requests from the WTRUs 100, the scheduler 222 generates rate assignments and sends them to WTRUs 100 via DL UE signaling channels 106. The speed grant provides information that determines the set of TFC combinations from which the WTRU 100 can

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Select and indicate the maximum resources whose use is acceptable for the WTRU for E-DCH transmission. The scheduling unit 222 controls the reception of the speed request and the transmission of the speed grants in the corresponding UE signaling channel. Alternatively, a separate control unit (not shown) may be provided in the MAC-e unit 220 of the Node-B node to receive speed grant and speed grant assignments and the scheduler 222 may be provided outside the MAC-e 220 of the Node-B node.

[0024] The demultiplexer 224 demultiplexes the MAC-e PDUs to the MAC-d PDUs. Multiplexing of the MAC-d stream to the MAC-e PDU is handled in the WTRU 100 unit. Many MAC-d flows can be configured for one WTRU and can be multiplexed in the same MAC-e PDU. The combination of MAC-d flows that can be multiplexed in one MAC-e PDU is configured by the RNC 300. The multiplexed MAC-e PDUs are demultiplexed to MAC-d flows by the demultiplexer 224. The demultiplexing of the Node-B can result in a change the MAC-d or RLC PDU sequence, and the MAC-e PDU sequence change can be performed by the RNC 300 controller.

[0025] The change of order may be performed either in the MAC-e of the Node-B node, where the H-ARQ process number is known, or in the MAC-e of the RNC controller. Referring again to Figure 2, the MAC-e 320 of the RNC controller includes a reordering unit to change the order of received MAC-e units by sequential transmission number (TSN).

PDU compatible with the received MACU PDUs with consecutive numbers

The TSNs are delivered to the separation function and the PDUs with the missing lower number

The TSNs are not provided for the separation function. The separation function deletes the MAC-e header before sending it to the higher one

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Layer. The RNC 300 controller includes multiple reordering queues to reorder the PDUs with different priority classes.

[0026] In the case where the reordering is carried out in the RNC MAC-e entity, the Node-B 200 transmits the H-ARQ process number with successfully decoded data to the RNC 300. The H-ARQ process may also be indirectly known by the reception time in the Node-B node passed to the RNC controller. The H-ARQ process number can be indirectly determined either from the system frame number (SFN) or from the connection frame number (CFN) along with the knowledge of the H-ARQ process allocation scheme in the WTRU 100 unit.

[0027] The H-ARQ 226 entity generates ACK acknowledgments and NACK acknowledgment indications indicating the delivery status of the E-DCH channel transmission. One H-ARQ unit can support multiple instances of H-ARQ "stop and wait".

[0028] Figure 5 is a block diagram of the MAC-e architecture of the WTRU 100 and node Node-B 200 together with signaling processes between the WTRU 100 and the Node-B node 200 in accordance with the present invention. When the MAC unit 120 of the WTRU receives data from the WLC layer 140 of the WTRU to be transmitted via the E-DCH 102 in step 502, the UE speed request unit 122 sends a speed request to the Node-B node (step 504). The Node-B node 200 corresponds to the speed grant (step 506). Upon receipt of the speed grant, the UE speed request unit 122 notifies the priority serving unit 124 that the radio resources are available for data transmission (step 508). The priority serving unit 124 then multiplexes the data and assigns the H-ARQ process according to the priority of the data,

510, 512). Data is transmitted with the assigned H-ARQ process

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EP 2 276 301 B1 via channel E-DCH 102 (step 514). The Node-B node 200 sends a feedback signal via DL UE signal channel 106 (step 516). If the response is NACK confirmation, the data may be autonomously retransmitted (step 518), or may be retransmitted after the next speed grant (step 520).

[0029] Although the features and elements of the present invention are described in preferred embodiments in particular combinations, each feature or element may be used alone without other features and elements of preferred embodiments or in various combinations with or without other features and elements of the present invention. .

[0030] Although the present invention has been described in terms of a preferred embodiment, other variations will be apparent to those skilled in the art which fall within the scope of the invention as defined in the claims below.

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