HK1188521A - Access point and method for dynamically allocating harq processes - Google Patents

Abstract

The present invention provides a method for dynamically allocating hybrid automatic repeat request HARQ processes and an access point for dynamically allocating HARQ processes. The method comprises: defining a system resource unit, wherein the system resource unit includes at least one HARQ process and a transmit power level; and allocating the system resource unit to at least one wireless transmit/receive unit WTRU. The access point comprises: a processor configured to: define a system resource unit, wherein the system resource unit includes at least one HARQ process and a transmit power level; and allocate the system resource unit to at least one wireless transmit/receive unit WTRU.

Description

Method and access point for dynamically allocating HARQ processes

The present application is a divisional application of the chinese patent application having an application date of 2007, 20/8, application number of 200780031352.1, entitled "method and apparatus for dynamically allocating HARQ processes in uplink".

Technical Field

The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus for dynamically allocating hybrid automatic repeat request (HARQ) processes for a wireless transmit/receive unit (WTRU) in the uplink.

Background

In Code Division Multiple Access (CDMA) based systems, such as high speed diversity access (HSPA), or single channel frequency division multiple access (SC-FDMA) systems, such as evolved universal terrestrial radio access network (E-UTRAN), uplink capabilities are limited by interference. For CDMA based systems, uplink interference at a particular cell site is typically generated by WTRUs (i.e., users) connected to that cell as well as other cells. In the case of SC-FDMA based systems, uplink interference occurs primarily at WTRUs connected to other cells. To maintain coverage and system stability, a cell site can only tolerate up to a certain amount of uplink interference at any given instant in time. As a result, system capacity is maximized if interference can remain unchanged as a function of time. This consistency allows a maximum number of users to transmit and/or generate interference, while at any time the uplink interference does not exceed a predetermined threshold.

High speed uplink diversity access (HSUPA) as defined in the third generation partnership project (3 GPP) release 6 employs HARQ with synchronous retransmissions. When using 2 millisecond (ms) Transmission Time Intervals (TTIs), the minimum instantaneous data rate is often greater than the data rate provided by the application due to the need to transmit a large number of bits, at least the size of a single Radio Link Control (RLC) Protocol Data Unit (PDU) in a given TTI. When this occurs, the WTRU may only use a subset of the available HARQ processes. As a result, the interference generated by a given active WTRU is not constant over a time span of eight (8) TTIs. During some TTIs, the WTRU transmits data and the interference it generates is high. During other TTIs, the WTRU may only transmit control information and thus it may generate less interference. To equalize interference among all TTIs, the system may constrain each WTRU to use a certain WTRU-specific subset of HARQ processes and select a different subset for different WTRUs.

The transmission of a certain data flow from a WTRU may be managed by an unscheduled transmission or a scheduled grant. With non-scheduled transmissions, the WTRU may transmit freely in a certain HARQ process up to a fixed data rate. With scheduling grants, the WTRU may also transmit on a certain HARQ process and up to a certain data rate, but the maximum data rate will change dynamically depending on the maximum power ratio signaled by the node B at a given time.

The set of HARQ processes is signaled to the WTRU by Radio Resource Control (RRC) signaling when the network manages transmissions by allowing non-scheduled transmissions. The node B determines the HARQ process set and signals this information to the Radio Network Controller (RNC), which then relays it to the user through RRC signaling. One advantage of managing delay sensitive traffic with non-scheduled transmissions is that it eliminates the possibility of any additional delay that may be caused by insufficient resources granted by the node B when managing transmissions with scheduled grants. Another advantage is that it eliminates the signaling overhead due to the transmission of scheduling information required by the scheduling grant.

However, with the currently defined unscheduled transmission mechanism, the system's performance is suboptimal when the application mix is dominated by delay-sensitive applications that generate traffic patterns that exhibit periods of high activity alternating periods of low activity. An example of such an application is a voice over IP (VoIP) application, where silence periods translate into very low traffic volume that needs to be transmitted. When a cell or system is dominated by such applications, capacity is maximized only when the network is able to change the subset of HARQ processes used by the WTRU when the WTRU's active state changes, so interference in the HARQ processes is always balanced. Otherwise, even when all WTRUs are active at the same time, the network must restrict the number of WTRUs using a certain HARQ process so as not to exceed the threshold, which results in a much lower capacity.

A problem with using non-scheduled transmissions is that it only allows the allowed subset of HARQ processes to be changed by RRC signaling, which typically involves delays of hundreds of milliseconds. This delay is quite large compared to typical intervals between changes in application activity that are used for applications such as audio applications. Also, the RRC signaling in the current release 6 structure is controlled by the RNC. Therefore, the node B needs to signal the RNC in advance the change of the allowed subset of HARQ processes. The time interval between the change in the active state of the WTRU and the effective change in the HARQ process may be greater than the duration of the active state. This therefore makes it infeasible to equalize interference among HARQ processes.

Therefore, it would be beneficial to provide a method and apparatus for dynamically allocating HARQ processes in the uplink, which would help optimize the system capacity using non-scheduled transmissions.

Disclosure of Invention

The invention discloses a method and equipment for dynamically allocating HARQ processes. In a wireless communication system including at least one WTRU and at least one Node B (NB), an activation or deactivation status for each of a plurality of HARQ processes is determined. A signal is transmitted to the WTRU that includes the activation or deactivation status of each HARQ process. The WTRU activates or deactivates a particular HARQ process in response to receiving the signal, based on an activation or deactivation status of each of a plurality of HARQ processes included in the received signal.

The invention discloses a method for dynamically allocating hybrid automatic repeat request (HARQ) processes, which comprises the following steps:

defining a system resource unit, wherein the system resource unit comprises a transmission power level and at least one HARQ process; and

allocating the system resource units to at least one wireless transmit/receive unit, WTRU.

The present invention also discloses an access point for dynamically allocating a hybrid automatic repeat request HARQ process, the access point comprising:

a processor configured to:

defining a system resource unit, wherein the system resource unit comprises a transmission power level and at least one HARQ process; and

allocating the system resource units to at least one wireless transmit/receive unit, WTRU.

Drawings

The invention will be understood in more detail from the following description of preferred embodiments, given by way of example and understood in conjunction with the accompanying drawings, in which:

figure 1 illustrates an exemplary wireless communication system including a plurality of WTRUs and a node-B;

figure 2 is a functional block diagram of the WTRU and node-B of figure 1;

FIG. 3A is a flow diagram of a process allocation method;

FIG. 3B is a flow diagram of an exemplary implementation of the method of FIG. 3A;

FIG. 4 is a flow diagram of a process allocation method according to an alternative embodiment;

FIG. 5 is an exemplary diagram of System Resource Unit (SRU) allocation according to the method of FIG. 4;

FIG. 6 is a flow diagram of a process allocation method according to an alternative embodiment; and

FIG. 7 is a flow diagram of a process allocation method according to an alternative embodiment.

Detailed Description

In the following description, the term "wireless transmit/receive unit (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, or any other type of device capable of operating in a wireless environment. Hereinafter, the 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.

Fig. 1 shows an exemplary wireless communication system 100, the wireless communication system 100 including a plurality of WTRUs 110, a Node B (NB) 120, and a Radio Network Controller (RNC) 130. As shown in fig. 1, the WTRU110 wirelessly communicates with an NB120 connected to an RNC 130. Although three WTRUs 110, one NB120, and one RNC130 are shown in fig. 1, it should be noted that any combination of wireless and wired devices may be included in the wireless communication system 100.

Fig. 2 is a functional block diagram 200 of the WTRU110 and the NB120 of the wireless communication system 100 of fig. 1. As shown in fig. 2, the WTRU110 communicates with the NB120 and both are configured to perform a dynamic process allocation method.

In addition to the elements that may be found in a typical WTRU, the WTRU110 includes a processor 115, a receiver 116, a transmitter 117, and an antenna 118. The processor 115 is configured to execute a dynamic process allocation program. The receiver 116 and the transmitter 117 are in communication with the processor 115. The antenna 118 is in communication with both the receiver 116 and the transmitter 117 to facilitate the transmission and reception of wireless data.

In addition to the elements that may be found in a typical NB, NB120 includes a processor 125, a receiver 126, a transmitter 127, and an antenna 128. The processor 115 is configured to execute a dynamic process allocation program. The receiver 126 and the transmitter 127 are in communication with the processor 125. The antenna 128 is in communication with both the receiver 126 and the transmitter 127 to facilitate the transmission and reception of wireless data.

Fig. 3A is a flow diagram of a process allocation method 300. In general, the method 300 involves signaling to the WTRU110 a subset of allowed HARQ processes. Preferably, the signaling is used for those non-scheduled transmissions using 2ms tti and the WTRU110 is able to use the method 300. Further, preferably, the information required for the start-up is delivered to the network by RRC signaling defined over one or more TTIs.

In step 310, activated or deactivated HARQ processes are identified and signaled to the WTRU110 or group of WTRUs 110 (step 320). This signaling may be performed in a variety of ways.

For example, in a preferred approach, each time a signal command is sent, an individual HARQ process is activated or deactivated depending on its current activity state. In this way, the number of bits required to be encoded depends on the maximum number of HARQ processes. For eight (8) HARQ processes as used in HSUPA, 3 bits would need to be signaled plus an additional bit indicating whether or not the HARQ process is to be activated/deactivated. The switching of the command signal between activation and deactivation may also be implicit, wherein the last unneeded bit is omitted. In this manner, however, the WTRU110 will have to know in advance how to decode the signal. Another possible approach is that one HARQ process is activated and another HARQ process is deactivated each time a command signal is sent. With this approach, then enough bits are needed to encode two HARQ processes (e.g., six (6) bits). In this manner, deactivated HARQ processes may be activated and activated HARQ processes may be deactivated. Alternatively, all active HARQ processes may be deactivated and all deactivated HARQ processes may be activated.

Steps 310 and 320 of method 300 may also be performed by implicitly signaling the activation or deactivation of individual HARQ processes in signaling transmission times, such as frames and subframes. For example, rules are pre-established between the signal command and the frame/subframe number of the involved HARQ process. In this way, no bits need to be required to describe individual HARQ processes, but the NB120 will be constrained to activate/deactivate individual HARQ processes only at specific frames or subframes. However, if it is desired to signal that a process is activated or deactivated, a single bit may be used. Alternatively, a combination of methods may be used, such as indicating deactivation of individual processes by transmission time and activation of processes by using one or more bits, or vice versa.

Another alternative to employing steps 310 and 320 of method 300 of fig. 3A is to use a signal command to immediately specify the activation or deactivation of all HARQ processes. This may be achieved by defining a bitmap where each bit represents one HARQ process and the value of the bit indicates whether the process should be activated or deactivated or the activation/deactivation status of the handover-only process.

It should be noted that under current technology conditions, the HARQ process numerator, also referred to as HARQ process index (index), is WTRU-specific. However, the RNC130 may adjust the numerator so that all WTRUs 110 in communication with the RNC130 may use the broadcast information. Alternatively, a particular WTRU110 may be signaled before communication is established between each bit of the bitmap and each HARQ process numerator (coreespondence).

For example, there may be eight (8) possible HARQ processes for each WTRU identified by an index (e.g., from 1 to 8). Because the WTRUs 110 are not synchronized with each other, the HARQ process N for a particular WTRU110 is typically not transmitted simultaneously with the HARQ process N for another WTRU 110. However, the NB120 may wish to activate or deactivate HARQ processes for multiple WTRUs 110, which are transmitted at a particular time. In order for this signaling to be possible with a "broadcast" scheme, the HARQ process indices of different WTRUs 110 should be synchronized so that the HARQ process N for a particular WTRU110 is transmitted simultaneously with the HARQ process N for any other WTRU 110. Alternatively, if the NB120 signals that all processes to be transmitted at a given time (possibly specified by some common reference) are to be turned on or off, each WTRU110 may be pre-signaled which process index is to be turned on or off.

In another implementation of steps 310 and 320 of method 300 of fig. 3A, WTRU110 may be allowed to use a separate process that has been "handoff off" if previously predefined or signaled from the network. One of the conditions may include a buffer occupied with data for WTRU110 uplink transmission. The number of bits associated with each individual process may vary and may indicate a usage priority, where different priorities would correspond to different sets of usage conditions for each respective individual process.

The number of bits may be equal to the maximum number of HARQ processes. For example, eight (8) bits are used for HSUPA. Alternatively, if the set of HARQ processes that may potentially be activated for a particular WTRU110 is less than the maximum number of HARQ processes possible, the number of bits required may be reduced. The set of potentially activated HARQ processes may be signaled to the WTRU110 by a higher layer (e.g., RRC) by employing the same approach as signaling the set of constrained HARQ processes.

The signaling command may also specify that the set of allowed HARQ processes (i.e., those HARQ processes that the WTRU110 may use for uplink transmissions) take effect immediately or a fixed delay after receiving the information from the WTRU 110. Alternatively, the updated set of allowed processes may take effect at a time specified in the signaling message itself. Preferably, the set of allowed HARQ processes is signaled as an index into a table, where a number of allowed HARQ process sets have been predefined and known to the WTRU 110. The number of bits representing the exponent will limit the number of sets that can be predefined. The mapping between the index and the set of allowed HARQ processes may be preconfigured by higher layer signaling, or the set of allowed HARQ processes may be explicitly signaled to the WTRU110 by enumerating a specific number of allowed processes.

Another way to implement steps 310 and 320 of method 300 of fig. 3A is to signal the probability that WTRU110 should turn on or off individual HARQ processes. Preferably, a single probability value is signaled (e.g. switched off) at each HARQ process, while a second probability value (e.g. switched on) is calculated according to a predefined rule using the signaled value. Alternatively, both the turn-on and turn-off probabilities may be explicitly signaled to the WTRU 110.

For any of the above methods, the signaling command may be sent (step 320) or directed to an individual WTRU110 or multiple WTRUs 110.

In a preferred embodiment, the functionality of the enhanced dedicated channel (E-DCH) absolute grant channel (E-AGCH) can be extended by defining an auxiliary decoding of the information bits. The correct decoding may be known to the WTRU110 by time division multiplexing in different TTIs and/or by using different spreading codes. The time and code may be signaled to the WTRU110 through the network. Alternatively, decoding may be implied by an identification code embedded in the E-AGCH, such as the WTRU ID. This is equivalent to defining a new physical channel with a new name, (e.g., enhanced active process indication channel (E-APICH), which may be time or code division multiplexed with the E-AGCH.

Currently, the E-AGCH identifies the WTRU110 by masking a Cyclic Redundancy Code (CRC) with a 16-bit enhanced radio network temporary identifier (E-RNTI). This approach may be extended by defining a secondary E-RNTI for non-scheduled transmissions of the WTRU110 that use both scheduled and non-scheduled transmissions. The WTRU110 should respond to more than one E-RNTI. It is also possible to separate scheduled and unscheduled operations in time. For processes that have been allowed to be used by the RNC130 for non-scheduled operations, the AGCH uses bit decoding as described in the above embodiments, while in other processes it uses bit decoding under current technology conditions.

In addition, the network may define groups of WTRUs 110 and E-RNTI values for these groups. This allows for faster signaling on the condition that some HARQ processes need to be deactivated for multiple WTRUs 110. Thus, a particular WTRU110 can be associated with a set of E-RNTI values, where a portion of the values may be common to multiple WTRUs 110. Further processing may be similar to that currently defined for E-AGCH, such as convolutional encoding with rate matching. Depending on the coding rate, the amount of rate matching, the CRC size, etc., there are additional possibilities to adapt the number of information bits needed on the E-AGCH or E-APICH. Preferably, the coding rate and rate matching should remain the same as the prior art E-AGCH in order to simplify the decoding operation at the WTRU 110. For example, the E-AGCH may include WTRU ID information (E-RNTI)/CRC (16 bits) and a 6-bit payload. Depending on how many bits are needed to encode the instruction, one or more E-AGCH transmissions may be combined by concatenating their available bits. In another example, the E-RNTI/CRC field may be reduced from 16 bits to a fewer number of bits to increase the number of available bits.

Another method of signaling the WTRU110 in step 320 may be to extend the E-RGCH/E-HICH functionality or to multiplex newly defined channels with these channels by using explicit orthogonal sequences to contain this new signaling. This selection allows transmission of binary values per TTI. One or more WTRUs 110 are identified by orthogonal sequences (signatures). It is also possible to transmit three (3) binary values by not combining the sequences in each of the three (3) slots of the TTI. However, this may require more transmission power. If the number of orthogonal sequences supporting the new signaling and the existing enhanced relative grant channel (E-RGCH)/enhanced HARQ indicator channel (E-HICH) is not sufficient, a different spreading code may be used to include the new signaling, which allows reuse of the orthogonal sequences of E-RGCH/E-HICH.

Alternatively, the format of the high speed shared control channel (HS-SCCH) may be modified to include the activation/deactivation order. The format for the auxiliary bits may be similar to the method for E-AGCH described above.

A wide variety of other techniques may be used in addition to the signaling method described above for step 320. For example, the existing Broadcast Control Channel (BCCH)/Broadcast Channel (BCH) may be extended to include activation/deactivation of individual HARQ processes related to signaling information. Existing RRC control signaling may be extended to convey information related to activation/deactivation of individual HARQ processes. The high speed medium access control (MAC-hs) header may be modified to include an activation/deactivation command, the format for the overhead bits potentially similar to one of the options described above for the E-AGCH. For this particular example, since retransmissions in the Downlink (DL) are asynchronous, and because the WTRU110 can typically only decode information when the downlink PDU decoding is successful, the signaling option in which the individual HARQ process is implicitly indicated by the signaling time should preferably refer to the transmission time of the HS-SCCH corresponding to the first transmission of this downlink PDU.

In order for signaling to be compatible with Discontinuous Reception (DRX) or Discontinuous Transmission (DTX) usage at the WTRU110, it may be necessary to impose a rule to force the WTRU110 to listen (i.e., not in DRX) during TTIs that are otherwise in DRX when certain conditions are met.

For example, the WTRU110 may be required to not use DRX for a certain period of time following the resumption or interruption of audio activity so that the NB120 may change activated HARQ processes when needed. Alternatively, the WTRU110 may be required to periodically listen during a TTI that is otherwise in DRX, according to a predetermined pattern. By way of further example, the WTRU110 may be required to stop DRX (i.e., listening in all TTIs) when the NB120 deactivates a HARQ process until another HARQ process is activated. Thus, an NB120 that wishes to change the HARQ process allocation of a particular WTRU110 will start by deactivating one of the HARQ processes for which it is known that the WTRU110 will listen for new HARQ process activation. Dialog rules (activation first and deactivation second) are also possible. In general, a rule may be established that allows the WTRU110 to activate DRX only when it activates a certain number of HARQ processes.

To ensure that the new set of HARQ processes corresponds to the DRX/DTX mode being used by the WTRU110, the network may signal DRX activation and/or DTX activation from the NB120 to the WTRU 110. Alternatively, the signaling may be done by higher layers. Since there is already an individual WTRU or group of WTRUs signaling that enables or disables a process under current technology conditions, it may be extended to indicate a multiprocess usage condition.

The embodiments can also support macro diversity. For example, a particular WTRU110 may be in a state where it transmits to one or more NBs 120 (additional NBs, not shown) in the active set in addition to its serving NB120, and then its serving NB120 transmits data to the RLC for macro combining. If the serving NB120 changes the assigned HARQ process, other cells in the active set may blindly detect uplink transmissions from the WTRU110 in the new HARQ process, or the serving NB120 signals the change to the RNC130, which then associates them with other NBs 120 in the active set.

Due to power control, all WTRUs 110 are considered interchangeable with respect to their contribution to uplink interference. Thus, the NB120 has the ability to select to which WTRU110 it transmits between processes. Thus, the NB120 may choose not to change the HARQ process allocation of the WTRU110 in handover.

As the WTRU110 moves within the system, changes to the E-DCH serving the NB120 will be required periodically. To support this mobility, several alternatives exist for the WTRU110 and NB120 characteristics during this period. In one example, the WTRU110 is allowed to transmit on any HARQ process that is not constrained by higher layers (i.e., all processes are active) until it receives an activation/deactivation command from the new serving NB 120. Alternatively, the WTRU110 may be prohibited from transmitting on any HARQ process (i.e., all processes are inactive) until it receives an activation command from the new serving NB 120.

However, in another preferred embodiment, the WTRU110 keeps the active/inactive state of each of its HARQ processes unchanged when the E-DCH serving NB120 changes. The new E-DCH serving NB120 then sends an activation/deactivation command to change the state of each HARQ process. The WTRU110 may ignore the command if the new serving NB120 sends a deactivation command for an already inactive HARQ process or sends an activation command for an already active HARQ process. Optionally, the new serving NB120 may signal the active/inactive status of the HARQ process of the WTRU110 through the RNC130 when establishing the radio link via Iub. Such signaling would require the old serving NB120 to signal this information to the RNC130 again via Iub before or when the E-DCH (enhanced data channel processor) serving node B changes.

The WTRU110 then reacts to the signaling it receives (step 330). This reaction may include several variations. In one example, the WTRU110 may listen at least when the MAC-e state changes from non-uplink data to uplink data. When there is new data already in the buffer and the N1TTI has elapsed, a change from no data to data is indicated. When no new data arrives in the buffer and the N2TTI has elapsed, a change from data to no data is indicated. N1 and N2 may be pre-signaled to WTRU110 through the network. If explicitly signaled, the WTRU110 must then enable or disable the process as indicated.

In an alternative example, if the WTRU110 is signaled as part of a group of WTRUs, the WTRU110 may randomly determine whether to execute the command by using the probability signaled by the network. To support synchronous retransmissions within a HARQ process, the WTRU110 should preferably only be allowed to switch to a different HARQ process when the current HARQ process is completed, i.e., a positive acknowledgement has been received or the maximum number of retransmissions has been met. Alternatively, if signaled as part of a group, the WTRU110 waits for a random amount of time before executing the instructions, where the random amount of time may have been previously signaled to the WTRU110 through the network.

When DRX or DTX is activated, and if the WTRU110 was previously instructed by higher layer signaling to do so, the WTRU110 adjusts its baseline for DRX and DTX modes to correspond to the time of the last DRX or DTX activation signal, respectively. Alternatively, the WTRU110 adjusts the DRX/DTX pattern to correspond to the set of HARQ processes signaled. The mapping of HARQ processes to DRX/DTX mode may be predetermined or may be signaled in advance by higher layer signaling.

In the current 3GPP release 6 architecture, the RRC layer is terminated at the RNC 130. When leaving control of the activation of HARQ processes to the NB120, the NB120 may need information regarding the quality of service (QoS) requirements of the WTRU110 to avoid an excessive reduction in the number of activated processes. Such a reduction in the number of activated processes in non-scheduled operation would undesirably force the WTRU110 to increase its instantaneous data rate during its active processes and reduce the area that can meet its QoS. Thus, it may be useful for the RNC130 to communicate information about the WTRU110 to the NB120, or for the NB120 to obtain the information in some other way.

For example, the RNC130 may estimate the minimum number of HARQ processes that need to be activated at a given time to support WTRU110 transmissions. The RNC130 has the ability to perform this estimation because it knows what the guaranteed bit rate is and it can control the throughput of the HARQ process through outer loop power control and HARQ profile management. The RNC130 communicates this number of HARQ processes to the NB120 via NBAP signaling. The NB120 ensures that the WTRU110 activates at least this number of HARQ processes at all times. This process may be desirable for NB120 for simplicity.

In addition, RNC130 may also provide the guaranteed bit rate to NB120 through NBAP signaling. Based on the guaranteed bit rate, the NB120 estimates how many active HARQ processes are needed at a given time and thus activates individual processes. NB120 may also determine to activate certain processes during the rest period.

Alternatively, the RNC130 may not provide any information to the NB 120. Conversely, with the constraint that the NB120 does not have to transmit more than one RLC PDU at a time unless all HARQ processes have been activated, the NB120 may try to keep the number of active HARQ processes for a given WTRU110 at the minimum possible value. By checking for successfully decoded MAC-e PDUs, NB120 can detect the transmission of more than one RLC PDU. This approach provides great flexibility to the NB120, but it may be more complex to implement.

Any HARQ process allocation changes and resulting DRX/DTX patterns or reference changes determined by the NB120 may be signaled to the RNC130, and the RNC130 may signal those changes to the target NB120 in case of handover.

Under current technology conditions, the set of HARQ processes that the WTRU110 is allowed to use is indicated by the RNC130 through L3 signaling. This signaling may be maintained indicating allowed HARQ processes for the WTRU110, which may be activated or deactivated by the NB120 according to various schemes described above. In addition, the RNC130 may indicate to the WTRU110 the initial set of HARQ processes to be activated.

Fig. 3B is a flow diagram of an exemplary implementation 305 of the method 300 of fig. 3A. In particular, the embodiment 305 allows the RNC130, NB120, and WTRU110 to optimize capacity, such as for VoIP or any other delay sensitive application. Whenever call setup is initiated (step 370), the particular WTRU110 is preferably provided with a list of potentially activated HARQ processes (step 375). Alternatively, if no list is provided, the WTRU110 may assume that it can potentially use all HARQ processes. Preferably, the RNC130 also provides information to the NB120 via the NBAP to assist the NB120 in determining the number of HARQ processes required.

After the WTRU110 starts transmitting, the NB120 starts deactivating the HARQ process where the system interference is the largest (step 380). In addition, the NB120 keeps the HARQ process in which interference is the smallest active state.

The NB120 then constantly monitors the activity of all allowed WTRUs 110 in a system employing non-scheduled transmissions and attempts to keep the interference among all HARQ processes below a certain threshold by changing the active HARQ processes with respect to activity (step 390). There are many ways to perform step 390.

One approach is for the NB120 to change the set of active HARQ processes for that WTRU110 to the HARQ process with the least interference when the NB120 detects that a previously inactive WTRU110 becomes active. Alternatively, if a previously active WTRU110 becomes inactive, it may swap its set of active HARQ processes with another set of active WTRUs 110. In addition, the NB120 may also deactivate most HARQ processes for a particular WTRU110 that has become inactive, and activate other HARQ processes such as the HARQ process in which interference is the least when activity resumes.

Another alternative is that the NB120 may monitor the interference on each HARQ process and periodically reallocate one of the HARQ processes of one WTRU110 from the most interfering HARQ process to the least interfering HARQ process, provided that the interference ceiling on all processes is not increased. That is, the HARQ process with the largest interference in the WTRU110 is deactivated and the HARQ process with the smallest interference in the WTRU110 is activated.

FIG. 4 is a flow diagram of a process allocation method 400 according to an alternative embodiment. Group intelligent allocation of system resources is possible for the WTRU110 because the purpose of the E-APICH is to maintain as balanced an uplink interference distribution as possible between HARQ processes.

In step 410 of method 400 of fig. 4, a System Resource Unit (SRU) is defined. Preferably, the SRU is defined as a combination of HARQ processes and fine grain amount (granularity) of interfering system resources such as rate or power. Preferably, interfering system resources are defined by considering that the amount of power or rate that a transmitter can simultaneously use in an interference limited system, such as a CDMA uplink, is limited. Using more resources than are available will cause interference and likely loss of packets. Although in the preferred embodiment the interfering system resources are typically measured using rate or power, other measurement methods may be used. In addition, the required signal-to-interference ratio (SIR), the received power, the uplink load (i.e. a fraction of the UL pole capacity) are measurement methods that can also be used.

In step 420 of the method 400 of figure 4, an SRU is assigned to the WTRU 110. In fact, all allocations in the current alternative embodiment of the present invention are done using SRUs. Preferably, the group of WTRUs 110 are selected and assigned the same non-scheduled SRU. This may be performed in various ways depending on how the SRU is defined. For example, if SRU = (HARQ process, power), the HARQ process may be allocated via RRC signaling, where power is allocated via a mechanism such as E-AGCH. All SRU processes within the group are assumed to be active and, therefore, all HARQ processes are active. Fast allocation is only used to allocate SRUs within the group. An optional SRU "barring" in the group is possible in order to ascertain that no WTRU110 in the group is using a particular HARQ process at a given time.

Assigning SRUs to groups of WTRUs may be performed by assigning SRUs to a single group, so if this is the only group transmission, the system resources are now exceeded and it is assured that there is successful communication. However, when there are multiple groups, the total number of allocated SRUs in a cell may exceed the total number of available SRUs.

Fig. 5 is an exemplary block diagram of a System Resource Unit (SRU) allocation in accordance with method 400 of fig. 4. In the example shown in fig. 5, it is assumed that the system supports 8 HARQ processes and can only support 3 SRUs simultaneously. No group of WTRUs is allocated an SRU and thus it may cause self-interference. However, twice the total number of SRUs available has been allocated, so that interference may occur if the WTRUs 110 all transmit at the same time. As shown in fig. 5, SRUs are assigned to groups of WTRUs 110 designated as group 1, group 2, group 3, and group 4. It should be noted, however, that the recitation of four clusters is exemplary, and any number of clusters is envisioned. The fast allocation of SRUs is then signaled by the NB120, preferably using the E-APICH, by allocating one or several SRUs to a group of WTRUs 110, wherein the NB120 ensures that no two WTRUs 110 in a particular group are allocated the same SRU.

There are several advantages and challenges in the group intelligence approach as described in method 400. Scheduling in the NB120 may be simplified by establishing a group of WTRUs 110. For example, HARQ allocations are semi-static between groups and dynamic only within a group. Clusters, on the other hand, provide sufficient degrees of freedom and sufficient response time to maintain a relatively stable interference profile.

In addition, signaling overhead may be reduced because only a single E-APICH is required for each group. All WTRUs 110 in the group monitor the same E-APICH. Moreover, a separate "power grant" to the WTRU110 is not required. A particular WTRU110 may always be granted more or less power by providing more SRUs to it or by removing a portion of the SRUs in a given HARQ process.

However, as the WTRU110 enters and leaves the cell, the group may need to be updated, which may result in an increase in signaling overhead. This problem may be alleviated by not updating the entire group each time the WTRU110 enters or leaves the group. Because a particular WTRU110 only needs to know its own group and its ID within the group, the group update overhead may be reduced.

For example, if the WTRU110 leaves the cell, its group is kept as it is, but the NB120 does not assign any SRU to the WTRU 110. Similarly, if the WTRU110 enters a cell, it may be added to an already open (open) group, for example, because the WTRU in the group previously left the cell, or a new group may be created with this WTRU110 as the only member of the group. Other WTRUs 110 may then be added to the newly created group. In any case, NB120 may occasionally have to reconfigure those groups. However, this will likely be a very rare event.

Depending on the scheduling procedure of the NB120, the rate required by the group size of the WTRUs 110 or the services supported by them may vary. Therefore, the method of forming the clusters is various.

For example, the total number of SRUs per cluster may be fixed. The number of WTRUs 110 per group may be fixed. The total number of specific individual resources (e.g., rate, power, HARQ processes) per group may be fixed. The group may include WTRUs 110 with similar receiver characteristics (e.g., x-type receivers with multiple-input multiple-output (MIMO) capabilities). The group may also include WTRUs 110 having similar channel qualities.

Although the multiplexing and signaling options for the group intelligent E-APICH are similar to those described above for the fast allocation per WTRU, the signaling options may need to be changed. Since all HARQ processes are assumed to be active for a group, the E-AGCH for a given TTI includes the group index of the WTRU110 to which the process is assigned. A specific index or a non-existent WTRU index may be used to disable HARQ processes for all WTRUs 110 in the group.

In addition, implicit signaling via transmission timing may not be practical for a group, although it may be used as overlapping signaling to prohibit HARQ processes. Further, instead of a bit field, a symbol (i.e., multi-bit) field is used, where each symbol indicates which WTRU110 is allowed a particular HARQ process and a WTRU index, which is a particular symbol or not present, may be used to prohibit the process. For example, each WTRU110 may be assigned a location of a bit field. A "0" may indicate that the WTRU assigned the location cannot use the process, and a "1" may indicate that the WTRU may use a specific process. Additionally, one of the bit field positions may not be assigned to a particular WTRU110, but rather is used to indicate that the process cannot be used by any or all WTRUs 110.

FIG. 6 is a flow diagram of a process allocation method 600 according to an alternative embodiment. In a current alternative embodiment, non-scheduled operation may be enhanced by sending a minimum downlink signaling including sufficient information to the WTRU110 to dynamically change the HARQ process within the constraints specified in the downlink signaling. The current RRC signaling for HARQ allocation for non-scheduled operations may be designed such that HARQ processes are constrained and staggered for the WTRU110 so that there is a smooth WTRU load distribution among the HARQ processes. However, this does not eliminate audio activity variations that may cause high interference during certain HARQ processes.

RRC signaling of the restricted and staggered HARQ allocations may be used to enhance non-scheduled operation. In step 610 of method 600, the RNC130 makes a HARQ assignment. A known controlled pattern/hop allocation may be used whenever a HARQ allocation is made (step 620). This known controlled pattern/hopping may be used to move the WTRU110 on top of the RNC130 allocation in such a way that the WTRU load per HARQ process remains as before, while the audio activity among the HARQ processes is eliminated. Preferably, a controlled pattern/hopping profile is known and the variation of audio activity is smoothed without disturbing the benefits of WTRU load distribution achieved by the constraints and interleaving of HARQ processes. In addition, it may also be defined by a constrained and staggered non-scheduled HARQ process allocation as follows.

The known controlled pattern/hopping is sent to a particular WTRU110 in a variety of ways (step 630). For example, it may be transmitted via RRC signaling or other downlink signaling, such as via the new physical channel E-APICH signaling described above. The mode, which may be signaled on a semi-static basis at call setup time or during a call/session, may require graceful adjustment of the previous allocations due to changes in the system, such as load changes.

In addition, the known controlled mode/hopping may take the form of any mode that generally maintains load balancing of the WTRU110 among the HARQ processes, which is provided by RRC allocation for non-scheduled operation. For example, based on a number of TTI periods that may be specified in RRC or other downlink signaling, a known controlled pattern/hopping may take the form of sequential hopping of HARQ processes from an initial RNC allocation. Sequential hopping is cyclic over the maximum number of HARQ processes and the hopping direction is chosen randomly with a probability of 0.5, for example.

Alternatively, the RRC may initially assign the WTRU110 a set of HARQ processes, and the WTRU110 may then periodically "hop" through the set of HARQ processes for certain multiple TTIs specified in the RRC or other downlink signaling. In another alternative, the WTRU110 hopping may be randomized based on the pseudo-random pattern and hopping period specified in the RRC or other downlink signaling.

In yet another alternative, the WTRU110 may randomly select the number of processes signaled for use in each of the 8-process cycles, e.g., or the WTRU110 may randomly decide whether to transmit in each TTI based on the probability that the WTRU110 may be signaled in advance. In another alternative, the probability may depend on WTRU uplink buffer occupancy as predefined by the network and signaling.

FIG. 7 is a flow diagram 700 of a process allocation method according to an alternative embodiment. In the method 700 illustrated in fig. 7, a HARQ process for an Uplink (UL) transmission is randomly selected by a particular WTRU110 during a selection opportunity. The selection opportunity occurs in every M TTIs, where M is preferably a multiple of multiple HARQ processes (e.g., 8, 16). The WTRU should be pre-configured with higher layers to select P HARQ processes on which it is allowed to transmit until the next selection opportunity.

In step 710, the RAN assigns a selection opportunity for each HARQ process. Preferably, the RAN provides a selection probability for each allowed HARQ process between 0 and 1, wherein the sum of the probabilities for all HARQ processes equals 1. This allows the RAN to support certain processes above other processes based on factors such as interference resulting from scheduling the WTRU110 and inter-cell interference. The random distribution used to select HARQ processes is signaled by the RAN to one or more WTRUs 110. The signaling of these parameters may be accomplished using any of the signaling mechanisms described above. The parameters may be signaled separately to each WTRU110, group of WTRUs 110, or immediately for all WTRUs 110. Preferably, the parameters may be updated with the HARQ process selection frequency of the WTRU110 or a slower frequency.

At each selection opportunity, the WTRU110 should retrieve the latest set of parameters signaled from the RAN (step 720). WTRU110 then selects the first HARQ process by randomly selecting a HARQ process from among the potential processes, taking into account the selection probability for each process (step 730).

If another process is needed (step 740), the WTRU110 randomly selects from among the remaining processes, taking into account the selection probability of the remaining processes (step 730). The process continues until the number of processes that the WTRU is allowed to transmit until the next selection opportunity (P) has been selected.

To support synchronous retransmissions within a HARQ process, the WTRU110 should preferably only be allowed to select a different HARQ process when the current HARQ process is completed, e.g., when a positive acknowledgement has been received or the maximum number of retransmissions has been met.

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 other features and elements of the preferred embodiments and each feature or element can be used in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium, examples of which 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, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any Integrated Circuit (IC), and/or a 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, or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a video circuit, a speakerphone, a vibration 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) module.

Examples

1. A method for dynamically allocating hybrid automatic repeat request (HARQ) processes in a wireless communication system including at least one wireless transmit/receive unit (WTRU) and at least one node-B (NB).

2. The method of embodiment 1, further comprising determining an activation or deactivation status for each particular HARQ process.

3. The method of any preceding embodiment, further comprising transmitting a signal to at least one WTRU, wherein the signal includes an activation or deactivation status for each particular HARQ process.

4. The method of any preceding embodiment, further comprising: in response to receiving the signal, the WTRU activates or deactivates a particular HARQ process according to an activation or deactivation status included in the received signal for each particular HARQ process.

5. The method of any preceding embodiment, wherein at least one WTRU uses non-scheduled transmissions of a 2 millisecond (2 ms) Transmission Time Interval (TTI).

6. A method as in any preceding embodiment, wherein a separate HARQ process is activated or deactivated each time a signal is transmitted.

7. A method as in any preceding embodiment, wherein a bit in the signal indicates an activation or deactivation status of a particular HARQ process.

8. A method as in any preceding embodiment, wherein the particular HARQ process is indicated by a signaling transmission time.

9. The method of any preceding embodiment, wherein: in response to the signal, the WTRU changes the state of the HARQ process.

10. The method of any preceding embodiment, wherein the WTRU changes HARQ processes in an active state to a deactivated state and changes HARQ processes in a deactivated state to an active state.

11. A method as in any preceding embodiment, wherein the transmitted signal indicates activation or deactivation of all HARQ processes.

12. The method of any preceding embodiment, further comprising defining a bitmap, wherein each particular bit represents an individual HARQ process and a value of each particular bit indicates an activation or deactivation status of the represented HARQ process.

13. A method as in any preceding embodiment, wherein the transmitted signal comprises a set of allowed HARQ processes.

14. The method of any previous embodiment, wherein the WTRU starts using the allowed procedures upon receipt of a signal.

15. The method of any previous embodiment, wherein the WTRU starts using the allowed processes after a certain delay.

16. A method as in any preceding embodiment, wherein the transmitted signal comprises a probability value for activating or deactivating a particular HARQ process.

17. The method of any preceding embodiment, wherein the transmitted signal is transmitted to a single WTRU.

18. The method of any preceding embodiment, wherein the transmitted signal is transmitted to a group of WTRUs.

19. A method as in any preceding embodiment, further comprising extending an enhanced dedicated channel (E-DCH) absolute grant channel (E-AGCH).

20. The method of any preceding embodiment, further comprising secondary decoding defined for information bits in the E-AGCH.

21. A method as in any preceding embodiment, further comprising defining an additional communication channel.

22. The method of any preceding embodiment, wherein the additional communication channel is an enhanced active process identification channel (E-APICH).

23. The method of any preceding embodiment, further comprising time-division multiplexing the E-APICH with the E-AGCH.

24. The method of any preceding embodiment, further comprising code division multiplexing the E-APICH with the E-AGCH.

25. A method as in any preceding embodiment, further comprising defining an enhanced radio network temporary identifier (E-RNTI) for the non-scheduled transmission.

26. The method as in any preceding embodiment, wherein an E-RNTI is defined for a group of WTRUs.

27. The method of any preceding embodiment, further comprising extending an enhanced relative grant channel (E-RGCH)/enhanced HARQ indicator channel (E-HICH).

28. The method of any preceding embodiment, further comprising multiplexing additional channels with the E-RGCH/E-HICH.

29. A method as in any preceding embodiment, further comprising spreading the transmitted signal with a spreading code.

30. A method as in any preceding embodiment, further comprising modifying a high speed synchronization control channel (HS-SCCH) to include the activation and deactivation information.

31. A method as in any preceding embodiment, further comprising altering a Broadcast Control Channel (BCCH)/Broadcast Channel (BCH) to include the activation and deactivation information.

32. A method as in any preceding embodiment, further comprising modifying a medium access control-high speed (MAC-hs) header to include activation and deactivation information.

33. The method of any preceding embodiment, further comprising requiring the WTRU not to use Discontinuous Reception (DRX) or Discontinuous Transmission (DTX).

34. The method of any preceding embodiment, further comprising an NB in another cell detecting uplink transmissions from the WTRU on a new HARQ process.

35. The method of any preceding embodiment, wherein a serving NB of a particular WTRU transmits a HARQ process change to a Radio Network Controller (RNC).

36. The method of any previous embodiment, wherein the WTRU maintains the activated and deactivated states of the HARQ process when changing an enhanced dedicated channel (E-DCH).

37. A method as in any preceding embodiment, further comprising the RNC estimating a minimum number of HARQ processes to be activated.

38. The method of any preceding embodiment, further comprising defining a System Resource Unit (SRU), wherein the SRU comprises at least one HARQ process and interfering system resources.

39. The method of any preceding embodiment, further comprising allocating SRUs to at least one WTRU.

40. A method as in any preceding embodiment, wherein the interfering system resources comprise rate or power.

41. The method of any preceding embodiment, wherein the same non-scheduled SRUs are allocated to a group of WTRUs.

42. The method of any previous embodiment, wherein a WTRU is added to an open group of WTRUs when the WTRU enters a particular cell served by an NB.

43. The method of any preceding embodiment, wherein the WTRU is added to a new group as a first WTRU when the WTRU enters a particular cell served by an NB.

44. The method of any preceding embodiment, wherein the size of the group of WTRUs is defined by a fixed number of SRUs.

45. The method of any preceding embodiment, wherein the size of the group of WTRUs is defined by a fixed number of WTRUs defining the group size.

46. The method of any preceding embodiment, wherein the size of the group of WTRUs is defined by a fixed total number of individual resources per group.

47. The method of any preceding embodiment, wherein the individual resources comprise any one of: rate, power, and HARQ process.

48. The method of any preceding embodiment, wherein the size of the group of WTRUs is defined by WTRUs having similar receiver characteristics.

49. The method of any preceding embodiment, wherein the size of the group of WTRUs is defined by WTRUs having similar channel qualities.

50. The method of any preceding embodiment, wherein a HARQ process is included in a group index in an E-AGCH, the HARQ process being activated for a particular group of WTRUs.

51. A method as in any preceding embodiment, further comprising the RNC allocating HARQ processes.

52. The method of any preceding embodiment, further comprising assigning a known controlled pattern/hop for the WTRU.

53. The method of any preceding embodiment, further comprising transmitting a known controlled pattern/hop to the WTRU.

54. The method of any previous embodiment, wherein a known controlled pattern/hop is transmitted to the WTRU at call setup.

55. The method of any previous embodiment, wherein a known controlled pattern/hop is transmitted to the WTRU during a call session.

56. A method as in any preceding embodiment, wherein the known controlled pattern/hopping comprises sequential hopping from an initially allocated HARQ process.

57. The method of any preceding embodiment, wherein the known controlled pattern/hopping is based on a number of Transmission Time Interval (TTI) periods.

58. A method as in any preceding embodiment, wherein the known controlled pattern/hopping comprises a rotation of HARQ processes.

59. The method of any preceding embodiment, wherein the rotation direction is randomly assigned according to a particular likelihood.

60. The method as in any preceding embodiment, wherein the known controlled pattern/hopping comprises a WTRU random handover from one HARQ process to another HARQ process.

61. A method as in any preceding embodiment, further comprising assigning a selection probability parameter to each individual HARQ process.

62. The method of any preceding embodiment, further comprising the WTRU retrieving a selection probability parameter.

63. The method of any preceding embodiment, further comprising the WTRU randomly selecting a HARQ process from the available HARQ processes based on the retrieved selection probability parameter.

64. A method as in any preceding embodiment, wherein the selection probability parameter assigned for each individual HARQ process is between 0 and 1.

65. The method as in any preceding embodiment, wherein a sum of probabilities for all available HARQ processes is equal to one.

66. The method of any preceding embodiment, further comprising providing a list of potentially activated HARQ processes to the WTRU.

67. A method as in any preceding embodiment, further comprising deactivating a particular HARQ process.

68. The method of any preceding embodiment, further comprising monitoring activity of the WTRU.

69. A method as in any preceding embodiment, further comprising adjusting HARQ processes to maintain interference levels in all HARQ processes.

70. An NB configured to perform the method as described in any of the previous embodiments.

71. The NB as in embodiment 70 further comprising a receiver.

72. The NB as in any one of embodiments 70-71, further comprising a transmitter.

73. The NB as in any one of embodiments 70-72, further comprising a processor in communication with the receiver and the transmitter.

74. The NB as in any one of embodiments 70-73, wherein the processor is configured to provide the WTRU with a list of potentially activated HARQ processes.

75. The NB as in any one of embodiments 70-74, wherein the processor is configured to deactivate a specific HARQ process.

76. The NB as in any one of embodiments 70-75, wherein the processor is configured to monitor activity of the WTRU.

77. The NB as in any one of embodiments 70-76, wherein the processor is configured to adjust HARQ processes to maintain interference levels in all HARQ processes.

78. The NB as in any one of embodiments 70-77, wherein the processor is configured to determine the activation or deactivation status for each particular HARQ process.

79. The NB as in any one of embodiments 70-78, wherein the processor is configured to transmit a signal to at least one WTRU, the signal including an activation or deactivation status for each particular HARQ process.

80. The NB as in any one of embodiments 70-79, further comprising an antenna in communication with the receiver and the transmitter, the antenna configured to facilitate wireless transmission and reception of data.

81. A WTRU configured to perform the method of any of embodiments 1-69.

82. The WTRU of embodiment 81, further comprising a receiver.

83. The WTRU as in any one of embodiments 81-82 further comprising a transmitter.

84. The WTRU as in any one of embodiments 81-83 further comprising a processor in communication with the receiver and the transmitter.

85. The WTRU as in any one of embodiments 81-84 wherein the processor is configured to receive a signal including an activation or deactivation status for each particular HARQ process.

86. The WTRU as in any one of embodiments 81-85 wherein the processor is configured to activate or deactivate a particular HARQ process based on an activation or deactivation status for each particular HARQ process included in the received signal.

Claims (20)

1. A method for dynamically allocating hybrid automatic repeat request, HARQ, processes, the method comprising:

defining a system resource unit, SRU, wherein the system resource unit, SRU, comprises a transmission power level and at least one hybrid automatic repeat request, HARQ, process; and

allocating the system resource unit SRU to at least one wireless transmit/receive unit WTRU.

2. The method of claim 1, wherein the transmission power level comprises a rate value or a power value.

3. The method of claim 1, wherein the same non-scheduled System Resource Unit (SRU) is allocated to a group of wireless transmit/receive units (WTRUs).

4. The method of claim 3, further comprising adding a wireless transmit/receive unit (WTRU) to an open group of WTRUs.

5. The method of claim 3, further comprising adding a wireless transmit/receive unit (WTRU) as the first WTRU to the new group.

6. The method of claim 3 wherein a size of a group of wireless transmit/receive units (WTRUs) is defined by a fixed number of System Resource Units (SRUs).

7. The method of claim 3 wherein a size of a group of wireless transmit/receive units (WTRUs) is defined by a fixed number of wireless transmit/receive units (WTRUs) defining the group size.

8. The method of claim 3 wherein a size of a group of wireless transmit/receive units (WTRUs) is defined by a fixed total number of individual resources per group.

9. The method of claim 8, wherein the individual resources comprise any one of: rate, power, or hybrid automatic repeat request HARQ process.

10. The method of claim 3 wherein a size of a group of wireless transmit/receive units (WTRUs) is defined by wireless transmit/receive units (WTRUs) having similar receiver characteristics.

11. The method of claim 3 wherein a size of a group of wireless transmit/receive units (WTRUs) is defined by wireless transmit/receive units (WTRUs) having similar channel qualities.

12. The method of claim 3 wherein hybrid automatic repeat request (HARQ) processes activated for a particular group of wireless transmit/receive units (WTRUs) are included in a group index in an enhanced dedicated channel (E-DCH) absolute grant channel (E-AGCH).

13. An access point, AP, for dynamically allocating hybrid automatic repeat request, HARQ, processes, the access point, AP, comprising:

a processor configured to:

defining a system resource unit, SRU, wherein the system resource unit, SRU, comprises a transmission power level and at least one hybrid automatic repeat request, HARQ, process; and

allocating the system resource unit SRU to at least one wireless transmit/receive unit WTRU.

14. The access point, AP, of claim 13, wherein the transmission power level comprises a rate value or a power value.

15. The access point AP as claimed in claim 13, wherein the same non-scheduled system resource unit, SRU, is allocated to a group of wireless transmit/receive units, WTRUs.

16. The access point AP of claim 15, further comprising adding wireless transmit/receive units WTRUs to an open group of wireless transmit/receive units WTRUs.

17. The access point AP as recited in claim 15, further comprising adding a WTRU to the new group as the first wireless transmit/receive unit WTRU.

18. The access point AP as claimed in claim 15, wherein the size of the group of wireless transmit/receive units, WTRUs, is defined by a fixed number of system resource units, SRUs.

19. The access point AP as claimed in claim 15, wherein the size of the group of wireless transmit/receive units WTRU is defined by a fixed number of wireless transmit/receive units WTRU defining the group size.

20. The access point AP as claimed in claim 15, wherein the size of the groups of wireless transmit/receive units WTRU is defined by a fixed total number of individual resources per group or by wireless transmit/receive units WTRU with similar channel quality.