HK1168225A - Method and apparatus for generating a radio link control protocol data unit for multi-carrier operation - Google Patents

Description

Method and apparatus for generating radio link control protocol data units for multi-carrier operation

Cross-referencing of related applications

This application claims benefit of U.S. provisional application No.61/172,499 filed on 24/4/2009 and is hereby incorporated by reference in its entirety.

Technical Field

The present application relates to wireless communications.

Background

Radio Link Control (RLC) entities in a wireless transmit/receive unit (WTRU) and a UMTS Terrestrial Radio Access Network (UTRAN) may operate in a Transparent Mode (TM), Unacknowledged Mode (UM), or Acknowledged Mode (AM). The UM RLC entity and the TM RLC entity may be configured as a transmission RLC entity or a reception RLC entity. The transmitting RLC entity transmits RLC Protocol Data Units (PDUs) and the receiving RLC entity receives RLC PDUs. The AM RLC entity includes a transmission side and a reception side. The transmitting side of the AM RLC entity transmits RLC PDUs and the receiving side of the AM RLC entity receives RLC PDUs.

Fig. 1A and 1B show conventional UM and AM RLC PDU formats, respectively. The sequence number field indicates a sequence number of the RLC PDU. The length indicator field is used to indicate the last octet (octet) at the end of each RLC Service Data Unit (SDU) in the RLC PDU. RLC SDUs or segments of RLC SDUs are mapped to data fields.

Conventionally, in Uplink (UL) configured by a network via Radio Resource Control (RRC) signaling, an AM RLC entity may generate an RLC PDU having a fixed size. Similarly, the UM RLC entity may select an RLC PDU size from a set of limited configured sizes.

In third generation partnership project (3GPP) release 7, the RLC protocol is extended to support flexible RLC PDU sizes in the Downlink (DL) but not in the UL. In 3GPP release 8, flexible RLC PDUs are also allowed in the UL, so that AM and UM RLC entities are allowed to create RLC PDUs of variable size on the UL.

The network may configure an uplink radio bearer in a wireless transmit/receive unit (WTRU) to generate RLC PDUs having variable sizes between a minimum RLC PDU size and a maximum RLC PDU size, where the maximum and minimum sizes are configured by the RRC layer. More specifically, the WTRU may segment and/or concatenate uplink RLC SDUs to create RLC PDUs greater than or equal to a minimum UL RLC PDU size and less than or equal to a maximum UL RLC PDU size. If the data to be transmitted is not large enough to create an RLC PDU of the minimum UL RLC PDU size, the RLC entity may create an AM PDU of less than the minimum UL RLC PDU size. This eliminates the padding requirement in case the amount of available data is smaller than the minimum UL RLC PDU size.

To maximize transmission efficiency, the size of the RLC PDU should match the number of bits that will be allowed to be transmitted over the air interface for a given logical channel within the current Transmission Time Interval (TTI). This improves transmission efficiency and greatly reduces layer 2(L2) header overhead.

Under current 3GPP specifications, the RLC entity may create an RLC PDU at a given transmission opportunity based on the number of bits requested for a given logical channel from a Medium Access Control (MAC) entity. The RLC entity selects the size of the data field of the RLC PDU to match the data requested by the MAC entity for a particular logical channel. With this option, the RLC entity needs to wait until a transmission opportunity to acquire information from the MAC entity, and thus some latent problems may occur.

Alternatively, the RLC entity may create more RLC PDUs than are transmitted in the upcoming TTI. This option relaxes the processing requirements as it effectively creates a delay between the creation of the RLC PDU and its inclusion in the MAC PDU. The size of the RLC PDU is based on the number of bits allowed to be transmitted according to the current grant, scheduled or unscheduled.

In order to further improve the throughput of the wireless system, multi-carrier operation is considered in 3 GPP. In multi-carrier operation, the WTRU and the node B may transmit and receive via multiple carriers.

Flexible RLC PDU creation currently deals with the case of RLC PDUs transmitted via single carrier. The inventors have recognized that in multi-carrier operation, a WTRU may choose to transmit more than one MAC PDU in a given TTI via multiple carriers. Since channel conditions, available power, and grants may not be the same across carriers, techniques for flexible RLC PDU creation for multiple carriers are needed.

Disclosure of Invention

Apparatus and methods for efficient RLC PDU size determination and flexible RLC PDU creation for multi-carrier operation are disclosed. In one embodiment, the WTRU is configured to calculate a maximum amount of data allowed to be transmitted for each of the plurality of carriers in the current TTI, and select the RLC PDU data field size such that each RLC PDU multiplexed to the MAC PUD is matched to a minimum of the maximum amount of data calculated for the carriers. The calculation of the maximum amount of data may be based on, for example, the applicable current grant for each carrier for the current TTI. In case the amount of data in the outstanding pre-generated RLC PDUs for a particular logical channel is less than or equal to 4N times the minimum of the maximum amount of data allowed for transmission by the current grant applicable for the carrier of the current TTI, where N is the number of activated carriers, RLC PDUs for the following TTI may be generated. The maximum amount of data may be calculated based on the maximum remaining power on each carrier.

Drawings

A more particular understanding can be obtained from the following description which is given by way of example in connection with the accompanying drawings;

fig. 1A and 1B are format diagrams illustrating conventional UM and AM RLC PDU formats, respectively;

figure 2 is a block diagram illustrating a wireless communication system including a plurality of WTRUs, a node B, a Controlling Radio Network Controller (CRNC), a Serving Radio Network Controller (SRNC), and a core network;

figure 3 is a functional block diagram of a WTRU and a node-B of the wireless communication system of figure 2;

fig. 4 is a flow diagram of an example process for generating RLC PDUs, according to one embodiment.

Detailed Description

When referred to hereafter, the technical term "WTRU" includes but is not limited to a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a Personal Digital Assistant (PDA), a computer, a sensor, a machine-to-machine (M2M) device, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the technical term "base station" includes but is not limited to a node-B, a site controller, an Access Point (AP), or any other type of interfacing device capable of operating in a wireless environment. When referring to the following, the technical terms "carrier" and "frequency" may be used interchangeably and it should be understood that different systems may use different technical terms, such as "component carrier" in 3GPP Long Term Evolution (LTE).

Although the embodiments are disclosed with reference to control channels and data channels related to 3GPP High Speed Packet Access (HSPA), it should be noted that the embodiments are not limited to 3GPP HSPA, but are applicable to any wireless communication technology that currently exists or will be developed in the future, including but not limited to 3GPP LTE, LTE-advanced, CDMA2000, IEEE 802.xx, and the like. The embodiments described herein may be applied in any order or combination.

Referring to fig. 2, an exemplary wireless communication system 100 includes a plurality of WTRUs 110, a node B120, a Controlling Radio Network Controller (CRNC)130, a Serving Radio Network Controller (SRNC)140, and a core network 150. Together, the node B120 and the CRNC 130 are referred to as a Universal Terrestrial Radio Access Network (UTRAN).

As shown in fig. 2, the WTRU 110 communicates with the node B120, which communicates with the CRNC 130 and the SRNC140 via an Iub interface, and the CRNC 130 and the SRNC140 are connected via an Iur interface. Although three WTRUs 110, one node B120, one CRNC 130, and one SRNC140 are shown in fig. 2, any combination of wireless and wired devices may be included in the wireless communication system 100.

Figure 3 is a functional block diagram of a WTRU 110 and a node-B120 of the wireless communication system 100 of figure 2. As shown in fig. 3, according to any one of the embodiments, the WTRU 110 communicates with the node-B120 and both are configured to determine the RLC PDU size for multi-carrier operation and generate RLC PDUs.

In addition to the components that may be found in a typical WTRU, the exemplary WTRU 110 includes a processor 115, a receiver 116, a transmitter 117, a memory 118, and an antenna 119. The WTRU 110 (i.e., the processor 115, the receiver 116, and the transmitter 117) is configured to transmit and/or receive on the uplink and/or downlink via multiple carriers. Memory 118 is provided to store software including an operating system, application programs, and the like. According to any of the embodiments, the processor 115 may be configured to perform RLC PDU size determination and RLC PDU generation for multiple carrier operation, either alone or in association with software. The receiver 116 and the transmitter 117 are in communication with the processor 115. An antenna 119 is in communication with the receiver 116 and the transmitter 117 to facilitate the transmission and reception of wireless data.

In addition to the components that can be found in a typical node B, the exemplary node B120 includes a processor 125, a receiver 126, a transmitter 127, a memory 128, and an antenna 129. The node B120 (i.e., the processor 125, the receiver 126, and the transmitter 127) is configured to transmit and/or receive on the downlink and/or uplink via multiple carriers. According to any of the embodiments, the processor 125 may be configured to determine RLC PDU sizes and generate RLC PDUs for multiple carrier operation. The receiver 126 and the transmitter 127 are in communication with the processor 125. An antenna 129 is in communication with the receiver 126 and the transmitter 127 to facilitate the transmission and reception of wireless data.

According to one embodiment, the WTRU (i.e., the RLC entity of the WTRU) may be configured to select one RLC PDU size for all activated carriers, (equivalently the RLC PDU data field size when considering the header), and pre-generate RLC PDUs for the current and/or subsequent TTIs if the WTRU has data available for transmission.

The WTRU may be configured to select the size of the data field of the RLC PDU, whereby each RLC PDU to be multiplexed into a MAC PDU for any carrier matches the maximum amount of data allowed to be transmitted given by the minimum applicable current grant across carriers. For example, in the case where two carriers (e.g., a primary and a secondary carrier) are activated, the size of the data field of the RLC PDU may be selected such that each RLC PDU multiplexed into a MAC PDU (e.g., a MAC-iPDU) matches the following minimum value:

the maximum data volume allowed to be transmitted by the current authorization can be applied on the primary uplink frequency in the current TTI; and

the maximum amount of data that the current grant allows for transmission may be applied on the secondary uplink frequency in the current TTI.

A grant, i.e., a grant for enhanced dedicated channel (E-DCH) transmission, may be configured for each carrier. The grants may be scheduled grants and/or non-scheduled grants. For scheduled grants, the WTRU maintains a serving grant that is updated based on information received from the network. The serving grant directly specifies the maximum power that the WTRU may use on the E-DCH dedicated physical data channel (E-DPDCH) in the corresponding TTI. The serving grant is updated by an E-DCH absolute grant channel (E-AGCH) and an E-DCH relative grant channel (E-RGCH). The network also provides non-scheduling grants to the WTRU to configure the maximum block size that the WTRU may transmit on the E-DCH during the TTI.

The "applicable grant" corresponds to a scheduled grant or an unscheduled grant according to a logical channel. The applicable grant for a logical channel corresponds to a serving grant (i.e., a scheduled grant) if the logical channel belongs to a scheduled MAC-d flow. If the logical channel belongs to a non-scheduled MAC-d flow, the applicable grant for the logical channel corresponds to the non-scheduled grant configured for the corresponding MAC-d flow.

For dual carrier operation, non-scheduled flows may be allowed on the primary uplink frequency but not on the secondary uplink frequency. In this case, if the logical channel belongs to an unscheduled MAC-d flow, the RLC PDU data field size may be determined such that each RLC PDU to be multiplexed into a MAC PDU (i.e., MAC-i PDU) matches the amount of data that the unscheduled grant for the corresponding MAC-d flow allows to transmit. Thus, if non-scheduled flows are not allowed in the secondary frequency, the RLC PDU data field size may be selected such that it matches the following minimum:

maximum amount of data that the current grant (scheduled or non-scheduled) allows for transmission on the primary uplink frequency applicable during the current TTI; and

the maximum amount of data that the current grant (scheduled) applicable at the secondary uplink frequency during the current TTI allows to be transmitted.

Thus, if the WTRU is not allowed to transmit non-scheduled data on the secondary uplink frequency, the RLC PDU size for the logical channel belonging to the non-scheduled MAC-d flow is determined based on the applicable grant for the primary uplink frequency.

When determining the RLC PDU size or the size of the data field of the RLC PDU, the RLC PDU size will not exceed the configured maximum RLC PDU size and will not be less than the configured minimum RLC PDU size unless there is insufficient data available in the buffer.

For single carrier operation, for example, RLC PDUs may be pre-generated if the amount of data in the outstanding pre-generated RLC PDUs for a particular logical channel is less than or equal to four (4) times the maximum amount of data that the current grant (scheduled or unscheduled) allows for transmission applicable during the current TTI. According to one embodiment, for multi-carrier operation, a WTRU may be configured to pre-generate RLC PDUs in the case that the amount of data in outstanding pre-generated RLC PDUs for a particular logical channel is less than or equal to 4 × N times the minimum of the maximum amount of data that the applicable current grant for a carrier allows for transmission during the current TTI, where N is the number of active carriers. For example, in dual carrier operation, N is accordingly 2, so if the amount of data in the outstanding pre-generated RLC PDUs for the logical channel is less than or equal to 8 times the minimum of the maximum amount of data allowed to be transmitted for the carrier's applicable current grant during the current TTI (i.e., 4 × 2), then the WTRU is allowed to pre-generate RLC PDUs. For other examples, any integer multiple of the number of configured carriers may be configured other than 4N.

Fig. 4 is a flow diagram of an example process 400 for generating RLC PDUs, in accordance with one embodiment. The WTRU (i.e., the RLC entity of the WTRU) selects a logical channel (step 402). For example, the logical channel may be selected according to an E-DCH transport format combination (E-TFC) selection rule. The WTRU may be configured to determine whether there is data available for transmission on the selected logical channel (step 404). Alternatively, this may be a determination of a sufficient amount of data to exceed a threshold. Optionally, the WTRU may also be configured to determine whether pre-generation of RLC PDUs is allowed for the selected logical channel. If no data is available, and/or alternatively, if pre-generation of RLC PDUs is not allowed for the logical channel, then a determination is made as to whether another logical channel is available for processing (step 414). In this case, process 400 either branches back to step 402 for another logical channel selection or ends based on the determination in step 414.

If there is data available for the logical channel (optionally, pre-generation of RLC PDUs is allowed for the selected logical channel), the WTRU in this example determines whether the amount of data in outstanding pre-generated RLC PDUs for the selected logical channel in the previous TTI exceeds a configured threshold (step 406). For example, the configured threshold may be 4 × N times the minimum of the maximum amount of data that the applicable current grant for a carrier allows for transmission during the current TTI, where N is the number of activated carriers. If the configured threshold is exceeded, the WTRU in this example does not allow for pre-generation of more RLC PDUs for the logical channel, and the process 400 branches to step 414 to determine if there is another logical channel. If the configured threshold is not exceeded, the WTRU is allowed to pre-generate RLC PDUs for the logical channels. Alternatively, the WTRU is configured not to check whether it is allowed to pre-generate RLC PDUs (i.e., step 416 is skipped), but may proceed directly with the remaining steps (i.e., 408, 410, 412) to determine the RLC PDU size and how many RLC PDUs it may create. In the case where RLC PDUs cannot be pre-generated, the number of RLC PDUs that the WTRU may pre-generate will be equal to 1.

In pre-generating the RLC PDU, the WTRU in this example determines the type of logical channel (i.e., scheduled or non-scheduled) and determines the maximum amount of data that the current grant can allow for transmission on each carrier during the current TTI (step 408). If the logical channel belongs to a scheduled MAC flow, the applicable grant is a serving grant, and if the logical channel belongs to a non-scheduled MAC flow, the applicable grant is a non-scheduled grant configured for the corresponding MAC-d flow. Alternatively or additionally, the maximum amount of data will be calculated based on the power on each carrier (maximum remaining power, WTRU power headroom (headroom), etc.), as explained in detail below.

The WTRU in this example selects the size of the data field of the RLC PDU (equivalently the size of the RLC PDU) such that each RLC PDU multiplexed to a MAC PDU (e.g., MAC-PDU) matches the minimum of the maximum amount of data allowed to be transmitted in the activated carriers during the current TTI (scheduled or non-scheduled) (step 410).

The WTRU based on the selected RLC PDU data field size (e.g., X)_{RLC PDU size}) At least one RLC PDU for a subsequent TTI is generated for the selected logical channel (step 412). The WTRU in one example determines the amount of data (i.e., the number of RLC PDUs) to pre-generate for the logical channel as follows. The number of RLC PDUs pre-generated in the previous TTI is called K_{pre-generated}. The maximum amount of data that is allowed to be pre-generated without the RLC PDU being pre-generated (Kmax) may be determined to be 4 × N × X_{RLC PDU size}Where N is the number of activated carriers, X_{RLC PDU size}Is the minimum of the maximum amount of data that the current grant (scheduled or non-scheduled) allows for transmission on all carriers, applicable during the current TTI. Alternatively, according to any one of the embodiments described herein, X_{RLC PDU size}May correspond to the RLC PDU size that the WTRU is able to create based on the determination.

The WTRU may be configured to pre-generate RLC PDUs for the logical channel up to the remaining available space (K)_{remaining allowed}) It is calculated by the following formula:

K_{remaining allowed}＝min(K_{available data}，(K_{max，allowed data}-K_{pre-generated}) Equation (1)

Wherein K_{available data}Is the amount of data available for transmission of the logical channel. Alternatively, the WTRU may be configured to calculate K after considering the data to be transmitted in the current TTI_{remaining allowed}. More specifically, the WTRU may be configured to receive data from K if data is capable of or to be transmitted in the current TTI_{pre-generated}The amount of this data is subtracted. K if RLC PDU creation is performed after the E-TFC selection procedure and MAC-i/is PDU creation are completed_{pre-generated}Containing the remaining number of bits or bytes that have been pre-generated.

The WTRU may be configured to calculate the maximum number of RLC PDUs pre-generated for a logical channel (N) as follows_{MAX RLC PDU})：

N_{MAX RLC PDU}＝[K_{remaining allowed}/X_{RLC PDU size}]Equation (2)

Wherein [ x ]]To give a floor function (floor function) of the largest integer less than or equal to x, N_{MAX RLC PDU}Is a non-negative integer. This may result in lower RLC PDUs than the WTRU generated.

Alternatively, the WTRU may be configured to calculate the maximum number of rlc pdus generated for the logical channel as follows:

N_{MAX RLC PDU}＝[K_{remaining allowed}/X_{RLC PDU size}]equation (3)

Where [ x ] is a ceiling function (ceiling function) that gives the smallest integer greater than or equal to x. This may result in the generation of a slightly more coordinated RLC PDU.

Alternatively, the WTRU may be configured to generate N size X s_{RLC PDU size}Complete RLC PDU of [ K ]_{remaining allowed}/X_{RLC PDU size}]And generating another RLC PDU with a size equal to min (minimum RLC PDU size, mod (K)_{remaining allowed}，X_{RLC PDU size}))。

The WTRU may be configured to pre-generate RLC PDUs when data becomes available in the RLC entity regardless of the logical channel being multiplexed or allowed to be transmitted over a given TTI. For example, a WTRU may pre-generate RLC PDUs according to embodiments described herein even though the WTRU is not allowed to transmit scheduled or non-scheduled transmissions within a given TTI.

Alternatively, the WTRU may be configured to pre-generate RLC PDUs for a particular logical channel when data becomes available in the RLC entity and the WTRU is allowed to transmit that type of data for the logical channel in a given TTI. For example, if data becomes available for a logical channel configured as an unscheduled MAC-d flow, but the WTRU is not allowed to transmit unscheduled transmissions within a given TTI, the WTRU may be configured to not pre-generate RLC PDUs. Alternatively, this rule may be applied to the scheduled flows. Alternatively, for non-scheduled flows, the WTRU may be configured to pre-generate RLC PDUs after data arrives from higher layers if the non-scheduling grant for the corresponding MAC-d flow is semi-static.

Alternatively, the WTRU may be configured to pre-generate RLC PDUs when data is available and the WTRU is allowed to transmit data for the logical channel in a given TTI according to multiplexing constraints based on the priority of the MAC-d flow.

Alternatively, the WTRU may be configured to pre-generate RLC PDUs when data is available and the WTRU is able to multiplex the data in a given TTI (e.g., data from the logical channel will be transmitted in that TTI).

In the above embodiments, the WTRU may be configured to select the size of the data field of the RLC PDU (i.e., equivalently the size of the RLC PDU) such that each RLC PDU multiplexed to a MAC PDU (e.g., MAC-iPDU) matches the minimum of the maximum amount of data allowed to be transmitted on all carriers during the current TTI (scheduled or unscheduled).

Alternatively, the WTRU may be configured to select the size of the data field of the RLC PDU such that each RLC PDU multiplexed into a MAC PDU (e.g., MAC-i/is PDU) for any carrier matches the maximum amount of data allowed to be transmitted given the maximum value of the applicable current grant for the carrier.

Alternatively, the WTRU may be configured to select the size of the data field of the RLC PDU such that each RLC PDU multiplexed into a MAC PDU (e.g., MAC-i/is PDU) for any carrier matches the maximum amount of data allowed for transmission given by the sum of the applicable current grants for the carrier. In the case where the current grant is a scheduled grant that appears in terms of power ratio, the sum may be calculated by first summing the power ratios (on a linear element) and then determining the amount of data that may be transmitted at the summed power ratio. Alternatively, the sum may be calculated by first determining the amount of data transmitted with the separate grants and then summing these amounts of data.

Alternatively, the WTRU may be configured to select the size of the data field of the RLC PDU such that each RLC PDU multiplexed into a MAC PDU (e.g., MAC-i/is PDU) for any carrier matches the average of all applicable grants for all carriers given the maximum amount of data allowed to be transmitted. In the case where the current grant is a scheduled grant that appears in terms of power ratio, the average may be calculated by first calculating the average of the power ratios (on a linear element) and then determining the amount of data that may be transmitted at the average power ratio. Alternatively, the average may be calculated by first determining the amount of data that can be transmitted with independent authorization and then calculating the average of these amounts of data.

Alternatively, the WTRU may be configured to select the size of the data field of the RLC PDU such that each RLC PDU multiplexed to a MAC PDU (e.g., MAC-i/is PDU) for any carrier matches the running average (running average) of the maximum amount of data allowed by the applicable grant for all carriers within a predetermined number of TTIs (or number of valid TTIs if an Infinite Impulse Response (IIR) filter is used).

According to another embodiment, the WTRU may be configured to create multiple sets of RLC PDUs, where the data field size of the RLC PDUs in each set is selected to match the maximum amount of data that is allowed to be transmitted by the grant applicable in each carrier. For example, if the WTRU is configured to communicate on two carriers, the WTRU may be configured to generate two sets of RLC PDUs for the two carriers, where the RLC PDU data field size in each set is selected to match the maximum amount of data that is allowed to be transmitted by the applicable grant in the respective carrier.

In any TTI, the WTRU may be configured to be limited by power rather than a grant. Thus, in determining the size of the RLC PDU data field (i.e., the maximum amount of data allowed to be transmitted for each carrier in the current TTI), the WTRU may optionally be configured to consider the power available on the carrier in addition to the grant.

Where each carrier is configured or allocated a separate maximum power, the WTRU may be configured, for example, to calculate the maximum remaining power allowed for E-DCH transmission on each carrier. The maximum remaining power allowed for E-DCH transmission for each carrier is a power calculated by subtracting a power required for a control channel, i.e., a Dedicated Physical Control Channel (DPCCH) and a high speed dedicated physical control channel (HS-DPCCH), from the maximum power allocated for the carrier. The WTRU may be configured to calculate the maximum amount of data that may be transmitted based on the current grant applicable on each carrier in the current TTI and the maximum remaining power allowed for E-DCH transmission. The WTRU may then be configured to select the data field size of the RLC PDU for RLC PDU pre-generation such that each RLC PDU multiplexed to a MAC PDU (e.g., MAC-i/is PDU) matches the minimum of the maximum amount of data on all carriers.

The maximum remaining power allowed for E-DCH transmissions may be calculated according to E-DCH transmission various combination (E-TFC) restriction mechanisms dedicated to multi-cell operation. When determining the maximum amount of data that may be transmitted on a given carrier based on the normalized remaining power, the WTRU may be configured to determine the supported E-TFC based on the power offset of the MAC-d flow corresponding to the given logical channel, or alternatively, based on the power offset of a higher priority MAC-d flow, or the power offset of the highest priority MAC-d flow (e.g., scheduled or non-scheduled) for that type of flow. The WTRU may be configured to also consider hybrid automatic repeat request (HARQ) offsets for the corresponding logical channels.

In the case where one maximum power is configured for all carriers to be shared by all carriers, the WTRU may be configured to calculate the maximum remaining power allowed for E-DCH transmission for each carrier based on the ratio of serving grants on the carriers after pre-allocating power for non-scheduled transmissions. The WTRU may be configured to assume that the applicable remaining power for each carrier may be used by the respective carrier. Alternatively, the WTRU may be configured to assume that half of the total available remaining power is available for each carrier.

For example, in dual carrier operation, the WTRU may be configured to first pre-allocate power for non-scheduled transmissions for one (or both) carriers and then divide the remaining values for scheduled transmissions according to the serving grant ratio (i.e., the serving grant ratio over the carriers). For example, if non-scheduled transmissions are not allowed on the secondary carriers, the maximum remaining power allowed for E-DCH transmissions on the primary carrier may be the sum of the power pre-allocated for non-scheduled transmissions and the power allocated for scheduled transmissions, which may be calculated based on the service grant ratio and a remaining value calculated by subtracting the power pre-allocated for non-scheduled transmissions and the power required for the control channels (i.e., DPCCH and HS-DPCCH) from the maximum power allocated for all carriers. The maximum remaining power allowed for E-DCH transmission on the secondary carriers may be the power allocated for scheduled transmission, which may be calculated based on the service grant ratio and a remaining value calculated by subtracting the power pre-allocated for non-scheduled transmission and the power required for the control channels (i.e., DPCCH and HS-DPCCH) from the maximum power allocated for all carriers.

These embodiments are equally applicable to operation with more than two carriers, whereby the normalized remaining power for each carrier may determine the maximum allowed data that can be transmitted on the carrier based on power.

The WTRU may be configured to determine the maximum amount of data K it may transmit based on the power and grant for each carrier_maxdata，xWhere x corresponds to the number of carriers. For example, for each carrier, a maximum amount of data based on the allocated power and the E-TFC restriction for that carrier and a maximum amount of data based on the serving grant for that carrier are determined, and K for that carrier_maxdata，xThe smallest of the two. The WTRU may be configured to determine the size of the data field of the RLC PDU for RLC PDU pre-generation as K in all carriers_maxdata，xIs measured. For example, if two carriers are activated (X ═ 1, 2), RLC PDU size (e.g., X) for RLC PDU pre-generation_{RLC PDU size}) Can be determined as K_maxdata，1And K_maxdata，2Minimum value of (1). Maximum and minimum configured RLC PDU values as described above may also be considered.

The power offset or the profile of the HARQ used to calculate the number of bits may be determined according to one embodiment described above.

According to another embodiment, the WTRU may be configured to determine the maximum amount of data that the current grant applicable on all carriers allows transmission in the current TTI (i.e., based on the minimum (or maximum, sum, or average) of grants applicable on all carriers). The WTRU then determines the maximum amount of data that the remaining power allows for transmission on all carriers in the current TTI. The WRTU then determines the size of the RLC PDU data field that needs to be pre-generated for the subsequent TTI to be the minimum of the maximum amount of data calculated based on the applicable grants on all carriers and the maximum amount of data calculated based on the remaining power on all carriers.

Examples

1. A method of generating RLC PDUs for multi-carrier operation.

2. The method of embodiment 1 comprising selecting a logical channel.

3. The method of embodiment 2 comprising determining whether there is data available for a logical channel.

4. A method as in any of embodiments 2-3 comprising calculating, for each carrier of a plurality of carriers, a maximum amount of data allowed to be transmitted within a current TTI.

5. The method of embodiment 4 comprising selecting an RLC PDU data field size for the logical channel whereby each RLC PDU multiplexed to the MAC PDU matches the minimum of the maximum amount of data calculated for the carrier.

6. The method of embodiment 5 comprising generating at least one RLC PDU for a subsequent TTI based on the selected RLC PDU data field size.

7. The method as in any one of embodiments 4-6 wherein the maximum amount of data that can be transmitted on each carrier is calculated based on the applicable current grant for each carrier in the current TTI.

8. The method as in any one of embodiments 6-7 wherein an RLC PDU is generated for a subsequent TTI where the amount of data in the outstanding pre-generated RLC PDUs for the logical channel is less than or equal to 4N times the minimum of the maximum amount of data allowed to be transmitted by the applicable current grant for the carrier in the current TTI, where N is the number of activated carriers.

9. The method as in any one of embodiments 7-8, wherein the applicable current grant is a non-scheduled grant if the logical channel belongs to a non-scheduled MAC flow and a serving grant if the logical channel belongs to a scheduled MAC flow.

10. The method of embodiment 9 wherein the primary carrier and the secondary carrier are activated.

11. The method of embodiment 10 wherein non-scheduled MAC flows are allowed on the primary carrier and scheduled MAC flows are allowed on the primary and secondary carriers.

12. The method of embodiment 11 wherein the RLC PDU data field size is selected for the logical channel such that each RLC PDU multiplexed to the MAC PDU matches the minimum of the maximum amount of data allowed to be transmitted on the primary carrier by the applicable currently scheduled or non-scheduled grant in the current TTI and the maximum amount of data allowed to be transmitted on the secondary carrier by the applicable currently scheduled grant in the current TTI.

13. The method as in any one of embodiments 4-12 wherein the maximum amount of data is calculated based on both the current grant applicable on each carrier and the maximum remaining power allowed for E-DCH transmission on each carrier.

14. The method of embodiment 13 wherein the maximum remaining power allowed for E-DCH transmission of a primary carrier is the sum of the power pre-allocated for non-scheduled transmission and the power allocated based on the serving grant ratio of the carrier, and the maximum remaining power allowed for E-DCH transmission of a secondary carrier is the power allocated based on the serving grant ratio of the carrier.

15. A WTRU generates RLC PDUs of varying sizes for multi-carrier transmission.

16. The WTRU of embodiment 15 comprising a transceiver configured to transmit or receive via a plurality of carriers.

17. The WTRU of embodiment 16 comprising a processor configured to select a logical channel.

18. The WTRU of embodiment 17 wherein the processor is configured to determine whether there is data available for a logical channel.

19. The WTRU as in any one of embodiments 17-18 wherein the processor is configured to calculate a maximum number of allowed transmissions in a current TTI for each of a plurality of carriers.

20. The WTRU of embodiment 19 wherein the processor is configured to select an RLC PDU data field size for the logical channel whereby each RLC PDU multiplexed to the MAC PDU matches the minimum of the maximum amount of data calculated for the carrier, and generate at least one RLC PDU for a subsequent TTI based on the selected RLC PDU data field size.

21. The WTRU as in any one of embodiments 19-20 wherein the processor is configured to calculate a maximum amount of data that can be transmitted on each carrier based on an applicable current grant for each carrier in a current TTI.

22. The WTRU as in any one of embodiments 20-21 wherein the processor is configured to generate an RLC PDU for a subsequent TTI on a condition that an amount of data in an outstanding pre-generated RLC PDU for a logical channel is less than or equal to 4N times a minimum of a maximum amount of data allowed to be transmitted for an applicable current grant of carriers in the current TTI, where N is a number of activated carriers.

23. The WTRU as in any one of embodiments 21-22 wherein the applicable current grant is a non-scheduled grant if the logical channel belongs to a non-scheduled MAC flow and a serving grant if the logical channel belongs to a scheduled MAC flow.

The WTRU of embodiment 23 wherein the primary carrier and the secondary carrier are activated and non-scheduled MAC flows are allowed on the primary carrier and the secondary carrier.

25. The WTRU of embodiment 24 wherein the processor is configured to select RLC PDU data field sizes for logical channels such that each RLC PDU multiplexed to a MAC PDU matches the minimum of the maximum amount of data allowed to be transmitted on the primary carrier by the applicable current scheduled or non-scheduled grant in the current TTI and the maximum amount of data allowed to be transmitted on the secondary carrier by the applicable current scheduled grant in the current TTI.

26. The WTRU as in any one of embodiments 21-25 wherein the maximum amount of data is calculated based on both a current grant applicable on each carrier and a maximum remaining power allowed for E-DCH transmissions on each carrier.

27. The WTRU of embodiment 26 wherein the maximum remaining power allowed for E-DCH transmission of a primary carrier is a sum of a power pre-allocated for non-scheduled transmission and a power allocated based on a serving grant ratio of a carrier, and the maximum remaining power allowed for E-DCH transmission of a secondary carrier is a power allocated based on the serving grant ratio of the carrier.

Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements. The methods or flow charts presented herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of the computer-readable storage medium include read-only memory (ROM), random-access memory (RAM), registers, buffer memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs).

Suitable processors include, for example, a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), any other type of logic circuitry and/or state machine.

A processor in association with software may be used to implement a radio frequency transceiver for use in a Wireless Transmit Receive Unit (WTRU), User Equipment (UE), terminal, base station, Radio Network Controller (RNC), or any host computer. The WTRU may be configured to be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a microphone, a vibrating device, a speaker, a microphone, a television transceiver, a hands-free headset, a keyboard, a bluetooth module, a Frequency Modulated (FM) radio unit, a Liquid Crystal Display (LCD) display unit, an Organic Light Emitting Diode (OLED) display unit, a digital music player, a media player, a video game player module, an internet browser, and/or any Wireless Local Area Network (WLAN) or Ultra Wideband (UWB) module.

Claims (14)

1. A method of generating a Radio Link Control (RLC) Protocol Data Unit (PDU) for multi-carrier operation, the method comprising:

selecting a logical channel;

determining whether there is data available for the logical channel;

calculating, for each of a plurality of carriers, a maximum amount of data allowed to be transmitted within a current Transmission Time Interval (TTI);

selecting an RLC PDU data field size for the logical channel whereby each RLC PDU multiplexed to a Medium Access Control (MAC) PDU matches a minimum of the maximum amount of data calculated for the carrier; and

generating at least one RLC PDU for a subsequent TTI based on the selected RLC PDU data field size.

2. The method of claim 1 performed by a wireless transmit/receive unit (WTRU) wherein the maximum amount of data that can be transmitted on each carrier is calculated based on an applicable current grant for each carrier in a current TTI.

3. The method of claim 2, wherein the RLC PDU for a subsequent TTI is generated in the event that the amount of data in the outstanding pre-generated RLC PDU for the logical channel is less than or equal to 4N times the minimum of the maximum amount of data allowed to be transmitted by the applicable current grant for the carrier in the current TTI, where N is the number of activated carriers.

4. The method of claim 2, wherein the applicable current grant for the first carrier of a current TTI is a non-scheduled grant if the logical channel belongs to a non-scheduled Medium Access Control (MAC) flow, and the applicable current grant for the second carrier of the current TTI is a serving grant if the logical channel belongs to a scheduled MAC flow.

5. The method of claim 4 wherein the first carrier is a primary carrier and a second carrier is a secondary carrier, and non-scheduled MAC flows are allowed on the primary carrier and the secondary carrier, and the RLC PDU data field size is selected for the logical channel such that each RLC PDU to be multiplexed to the MAC PDU matches the minimum of:

allowing a maximum amount of data to be transmitted on the primary carrier by an applicable current scheduled grant or non-scheduled grant within a current TTI; and

the maximum amount of data to be transmitted on the secondary carrier by the applicable current scheduling grant is allowed in the current TTI.

6. The method of claim 1, wherein the maximum amount of data is calculated based on both a current grant applicable on each carrier and a maximum remaining power allowed for enhanced dedicated channel (E-DCH) transmission.

7. The method according to claim 6, wherein the maximum remaining power allowed for E-DCH transmission of the primary carrier is a sum of a power pre-allocated for non-scheduled transmission and a power allocated based on a serving grant ratio of the carrier, and the maximum remaining power allowed for E-DCH transmission of the secondary carrier is a power allocated based on the serving grant ratio of the carrier.

8. A wireless transmit/receive unit (WTRU) for generating variable size Radio Link Control (RLC) Protocol Data Units (PDUs) for multicarrier transmission, the WTRU comprising:

a transceiver configured to wirelessly communicate using a logical channel via a plurality of carriers;

a processor configured to select a logical channel and determine whether data is available for the logical channel;

the processor is configured to calculate, for each of a plurality of carriers, a maximum amount of data allowed to be transmitted within a current Transmission Time Interval (TTI);

the processor is configured to select an RLC PDU data field size for the logical channel, thereby matching each RLC PDU multiplexed into a Medium Access Control (MAC) PDU with a minimum of the maximum amount of data calculated for the carrier; and

the processor is configured to generate at least one RLC PDU for a subsequent TTI based on the selected RLC PDU data field size.

9. The WTRU of claim 8 wherein the processor is configured to calculate a maximum amount of data that can be transmitted on each carrier based on an applicable current grant for each carrier in a current TTI.

10. The WTRU of claim 9 wherein the processor is configured to generate an RLC PDU for a subsequent TTI on a condition that an amount of data in outstanding pre-generated RLC PDUs for a particular logical channel is less than or equal to 4N times a minimum of a maximum amount of data allowed to be transmitted by an applicable current grant for the carrier in a current TTI, where N is a number of activated carriers.

11. The WTRU of claim 9 wherein the processor is configured to calculate a maximum amount of data that can be transmitted on a first carrier and a second carrier in a current TTI, wherein an applicable current grant for the first carrier is a non-scheduled grant on a condition that the logical channel belongs to a non-scheduled Medium Access Control (MAC) flow and an applicable current grant for the second carrier is a serving grant on a condition that the logical channel belongs to a scheduled MAC flow.

12. The WTRU of claim 11 wherein the first carrier is a primary carrier and a second carrier is a secondary carrier and non-scheduled MAC flows are allowed on the primary carrier and the secondary carrier, wherein the processor is configured to select RLC PDU data field sizes for the logical channels such that each RLC PDU to be multiplexed to the MAC PDU matches a minimum of:

allowing a maximum amount of data to be transmitted on the primary carrier by an applicable current scheduled grant or non-scheduled grant within a current TTI; and

the maximum amount of data to be transmitted on the secondary carrier by the applicable current scheduling grant is allowed in the current TTI.

13. The WTRU of claim 8 wherein the processor is configured to calculate the maximum amount of data based on both a current grant applicable on each carrier and a maximum remaining power allowed for enhanced dedicated channel (E-DCH) transmissions.

14. The WTRU of claim 13 wherein the processor is configured to calculate the maximum amount of data, wherein a maximum remaining power allowed for E-DCH transmission of the primary carrier is a sum of a power pre-allocated for non-scheduled transmissions and a power allocated based on a serving grant ratio of the carrier, and a maximum remaining power allowed for E-DCH transmission of the secondary carrier is a power allocated based on the serving grant ratio of the carrier.