Transport format combination selection in a wireless transmit/receive unit

The present invention relates to a wireless communication system, and more particularly to a method of selecting a combination of transmission formats (TFC) in a wireless transmission / reception device (WTRU).

Under the current 3GPP (Third Generation Partnership Project) standard, WTRU needs to evaluate the transmit power for each TFC. If a particular TFC is requested to transmit more than the maximum possible WTRU transmit power, the WTRU should limit the use of that TFC.

WTRU continuously evaluates the availability of TFC for transmission. The evaluation implements the use of the evaluated WTRU transmit power of the given TFC. If any TFC restricts the transmission power limit from being exceeded, the Medium Access Control (MAC) entry in the WTRU notifies the upper layer to slow down the data transfer rate, if appropriate.

Under the 3GPP standard, WTRU has only one integrated coded composite transport channel (CCTrCH) for uplink transmission. Therefore, the WTRU transmission power is the transmission power of the CCTrCH, and the transmission power of the CCTrCH is determined by the TFC used for the CCTrCH.

<p> In order to improve the uplink reception area, processing power, transmission latency, and enhanced uplink (EU) for uplink transmission are currently being investigated in 3GPP. With EU implementation, WTRU can have more than one CCTrCH in uplink transmission. One is for the regular dedicated channel (DCH) and the other is for the EU enlarged dedicated channel (E-DCH). In this case, the WTRU transmit power is the sum of the transmit powers of the two CCTrCHs.</p><p> The WTRU transmission power is jointly determined by the TFCs of the two CCTrCHs. The combination of the TFC used by the evaluated CCTrCH and the TFC used by the EU CCTrCH is defined as a TFC pair of WTRU transmit power jointly determined by the TFCs of the two CCTrCHs. This is not the best way to determine TFC for more than one CCTrCH.</p><p> Therefore, there is a need for an efficient method for selecting a combination of TFCs related to two or more CCTrCHs in uplink transmission.</p>

<p> The present invention relates to methods and devices for selecting TFC in WTRU. The WTRU is configured to handle more than one CCTrCH for uplink transmissions. The WTRU evaluates the transmit power for each of the multiple available TFCs so that the sum of the evaluated WTRU transmit powers for the selected TFC is less than or equal to the maximum WTRU transmit power allowed for each CCTrCH. Select.</p><p> WTRU can prioritize specific CCTrCH. The TFC for a particular CCTrCH was selected first, and the TFCs for other CCTrCHs were evaluated after the power required for the selected TFC in the prioritized CCTrCH was deducted from the maximum allowed WTRU transmit power. Selected within the remaining WTRU transmit power. This method allows transmission in which the channel mapped to the first CCTrCH is prioritized over the channel mapped to the other CCTrCH.</p><p> Or instead, WTRU can reserve a minimum set of TFCs for other CCTrCH. The TFC of the CCTrCH prioritized thereby is first selected within the maximum permissible WTRU transmit power that is less than the power required to support the minimum set of TFCs in other CCTrCHs. TFCs for other CCTrCHs are selected within the remaining WTRU transmit power after the power required for the selected TFC in the prioritized CCTrCH has been deducted from the maximum allowed WTRU transmit power. This method takes precedence over channels mapped to other CCTrCHs while accumulating transmit power that allows the minimum set of FCTs in other CCTrCHs transmitted without being satisfied by the maximum allowed WTRU transmit power limit. Allows transmission of channels mapped to the first CCTrCH to be made.</p><p> Alternatively, the WTRU can be set to its own maximum transmit power for each of the multiple CCTrCHs. Thereby, the TFC for each CCTrCH is selected for its respective maximum transmit power specified for each CCTrCH. This method allows each CCTrCH to be given quality of service (QoS) to other CCTrCHs. The function of one CCTrCH does not prioritize or reduce the proportion of other CCTrCH.</p>

<figref num="1">It is a figure which shows the flowchart of the general process concerning the selection of TFC which concerns on 1st Embodiment of this invention.</figref><figref num="2">It is a figure which shows the flowchart of the general process concerning the selection of TFC which concerns on 2nd Embodiment of this invention.</figref><figref num="3">It is a figure which shows the flowchart of the general process concerning the selection of TFC which concerns on 3rd Embodiment of this invention.</figref><figref num="4">It is a figure which shows the flowchart of the general process concerning the selection of TFC which concerns on 4th Embodiment of this invention.</figref><figref num="5">It is a figure which shows the block diagram of the apparatus concerning the selection of TFC which concerns on this invention.</figref>

Hereinafter, the term "WTRU" includes, but is not limited to, user equipment, mobile stations, fixed or mobile subscriber equipment, pagers, or any other equipment that can operate in a wireless environment.

The functions of the present invention are built into integrated circuits (ICs) or consist of circuits containing a large number of interconnected elements.

Hereinafter, the present invention will be described in relation to two CCTrCHs that support the system, namely a dedicated CCTrCH and an EU CCTrCH. However, it should be noted that the present invention is also applicable to systems that support more than one CCTrCH.

FIG. 1 shows a follow-up chart of step 100 relating to the selection of TFC according to the first embodiment of the present invention. The WTRU is configured to process dedicated CCTrCH and EU CCTrCH simultaneously for upstream transmission. The WTRU transmit power is limited to the maximum WTRU transmit power. The WTRU transmission power is set by the wireless communication system. At each transmit time interval (TTI), the WTRU evaluates the transmit power for each of the multiple available TFCs for each CCTrCH (step 102). The WTRU evaluates the transmit power of each TFC over a predetermined period of time, taking into account the gain factor of each corresponding TFC. The WTRU is then transmitted in each CCTrCH among multiple available TFCs so that the sum of the evaluated transmit powers of the selected TFCs for the dedicated CCTrCH and EU CCTrCH does not exceed the maximum allowed WTRU transmit power. Select the TFC for (step 104).

In addition, dedicated CCTrCH, EU CCTrCH, or both are given the ability to transmit a reserved minimum set of TFCs. This is true even when the power required to transmit those TFCs exceeds the maximum permissible WTRU transmit power. TFCs that require more power than the maximum permissible transmission power are defined as being in an overpowered state. The smallest set reserves the lowest percentage in CCTrCH and thus retains the basic service of the channel. In EU CC TrCH where only one TrCH exists, the minimum set corresponds to the lowest percentage per unit logical channel, or the MAC-d flow mapped to EU TrCH. The minimum set of TFCs is one transmission block per unit TTI for each channel mapped to CCTrCH, or multiple transmission blocks per unit TTI corresponding to the guaranteed bit rate (GBR).

The reserved minimum set of TFCs can be transmitted in overpowered conditions. To maintain transmit power over the maximum acceptable level, the WTRU reduces power on a dedicated CCTrCH, EU CCTrCH, or a physical channel mapped to all existing physical channels.

Regardless of the choice of TFC, EU CCTrCH can be given one or more transmission blocks per unit logical channel, or a reserved set of minimum TFC values that are MAC-d flows mapped to EU CCTrCH. .. A transmission block is one or more radio link control (RLC) protocol data units (PDUs). One or more transmission blocks are equivalent to the data rate. Reserved sets of TFCs can be transmitted in overpowered conditions by reducing power in EU CCTrCH, dedicated CCTrCH or physical channels mapped to all existing UL channels.

FIG. 2 shows the floater of step 200 relating to the selection of TFC according to the second embodiment of the present invention. Indicates. The TFC selection of the dedicated CCTrCH takes precedence over the TFC selection of the EU CCTrCH. For each TTI of the dedicated CCTrCH, the WTRU evaluates the transmission power requirements for each of the multiple available TFCs configured for the dedicated CCTrCH (step 202). The WTRU first selects the TFC for the dedicated CCTrCH without considering the power requirements of the EU CCTrCH (step 204). After the TFC for the dedicated CCTrCH is selected, in each TTI of the EU CCTrCH, the WTRU is within the remaining WTRU transmit power after the power required for the selected TFC for the dedicated CCTrCH is deducted from the maximum allowed WTRU transmit power. Select TFC for EU CC TrCH (step 206). The TFC selection of the dedicated CCTrCH is not affected by the operation of the EU CCTrCH. However, on the other hand, the EU CCTrCH's TFC selection is influenced and limited by the operation of the dedicated CCTrCH.

The remaining power for EU CCTrCH is evaluated at each dedicated CCTrCH TTI or each EU CCTrCH TTI. For each EU CCTrCH TTI, the remaining power available for the EU CCTrCH is evaluated as the power required to transmit the selected dedicated CCTrCH TFC minus the maximum allowed WTRU transmit power. Or instead, at each TTI of the dedicated CCTrCH, the remaining power available for the EU CCTrCH is the power required to support the transmission of the selected dedicated CCTrCH minus the maximum allowed WTRU transmit power. Be evaluated.

In step 200, EU CCTrCH is capable of transmitting a minimum set of TFCs. The same is true even if those TFCs are in an overpowered state. The EU TFC is in an overpowered state when the remaining power evaluated is lower than the predicted transmit power requirement for the EU CCTrCH TFC. The EU minimum set reserves the minimum or guaranteed speed for channels mapped to the EU CCTrCH and, as a result, retains basic services for EU channels. In EU CC TrCH where only one TrCH exists, the minimum set corresponds to the lowest speed per unit logical channel or the MAC-d flow mapped to EU TrCH. The minimum set of TFCs can be one transmission block per unit TTI for each channel mapped to CCTrCH, or multiple transmission blocks per unit TTI corresponding to the guaranteed transmission rate (GBR). In order to keep the transmit power below the maximum allowable level when transmitting TFC in overpower conditions, the WTRU is EU Reduce power in CCTrCH, dedicated CCTrCH, or physical channels mapped to all existing physical channels.

FIG. 3 shows a flowchart of step 300 relating to the selection of TFC according to the fourth embodiment of the present invention. The WTRU preferentially selects a dedicated CCTrCH TFC while reserving transmit power for the minimum set of EU CCTrCH TFCs (step 302). The minimum set of TFCs for EU CCTrCH is determined to reserve the minimum or guaranteed speed for channels mapped to EU CCTrCH. In EU CC TrCH where there is only one TrCH, the minimum set corresponds to the minimum speed per unit logical channel or the MAC-d flow mapped to EU TrCH. The minimum set of TFCs can be one transmission block per unit TTI for each channel mapped to CCTrCH, or multiple transmission blocks per unit TTI corresponding to GBR.

EU CCTrCH can allow transmission of a minimum set of TFCs even when they are overpowered. The EU TFC is in an overpower condition when the remaining power evaluated is lower than the expected transmit power requirements for the EU TFC. When transmitting TFC in an overpowered state, the WTRU uses EU CCTrCH, dedicated CCTrCH, or power in a physical channel mapped to all existing physical channels to keep the transmit power below the maximum allowable level. To reduce.

When the TFC is in an overpowered state (including reduced power), the quality of transmission is reduced (to lower SIR, higher BLER, etc.). Therefore, in order to minimize the possibility that the EU CCTrCH will be transmitted in an overpowered state and that it will be necessary to further guarantee the minimum set actually supported, the transmit power in step 300 will be selected by the TFC. Reserved for EU minimum set when implemented in preferred dedicated CCTrCH.

The TFC selection of the dedicated CCTrCH takes precedence over the TFC selection of the EU CCTrCH. For each TTI of the dedicated CCTrCH, the WTRU evaluates the transmit power for each of the multiple available TFCs configured for the dedicated CCTrCH and the TFC associated with the EU CCTrCH minimum set (step 304). The WTRU selects a TFC for a dedicated CCTrCH with a power requirement that does not exceed the maximum permissible transmit power minus the power required to support the minimum set of TFCs on the EU CCTrCH (step 306). After the TFC for the dedicated CCTrCH is selected, in each TTI of the EU CCTrCH the WTRU has the EU CCTrCH with the remaining transmit power after the power requesting the selected TFC for the dedicated CCTrCH has been deducted from the maximum allowable transmit power. Select the TFC for (step 308).

The remaining power for EU CCTrCH is evaluated at each dedicated CCTrCH TTI or at each EU CCTrCH TTI. For each EU CCTrCH TTI, the remaining power available for the EU CCTrCH is evaluated as the maximum permissible WTRU transmit power minus the power required by the transmission of the selected dedicated CCTrCH TFC. Or instead, at each TTI of the dedicated CCTrCH, the remaining power available for the EU CCTrCH is evaluated as the maximum allowable WTRU transmit power minus the power required to support the transmission of the selected dedicated CCTrCH TFC. Will be done.

The minimum set of EU CCTrCH TFCs is also reserved for power when the dedicated TFC is selected, as the selection of the dedicated CCTrCH TFC takes precedence over the EU CCTrCH and the power requirements can change between the dedicated TTIs. Regardless, it is still transmitted in the excess current state. In this situation, the WTRU shrinks the EU CCTrCH, the dedicated CCTrCH, or all physical channels that map to all existing physical channels in order to keep the transmit power below the maximum acceptable level.

FIG. 4 shows a flowchart of step 400 relating to the selection of TFC according to the third embodiment of the present invention. The WTRU sets the speed in relation to the individual maximum transmit power or the maximum allowable WTRU transmit power associated with the dedicated CCTrCH and EU CCTrCH (step 402). The maximum power level (or percentage) for each CCTrCH is a configurable parameter. Factors that determine the maximum power level (or percentage) of each CCTrCH include, but are not limited to, the data transfer rate of each CCTrCH, the quality of service (QoS) of each CCTrCH, and the relative priority between CCTrCHs.

At each TTI of the dedicated CCTrCH, and at each TTI of the EU CCTrCH, the WTRU evaluates the transmit power for each of the multiple available TFCs (step 404). The WTRU then selects a TFC for each CCTrCH that is less than or equal to the individual maximum transmit power for each CCTrCH (step 406). The TFC selection process for each CCTrCH operates independently. The TFC for each CCTrCH is selected from only those TFCs that can be supported by the individual maximum power levels defined for a particular CCTrCH.

Dedicated CCTrCH, EU CCTrCH, or both can gain the ability to carry a minimum set of TFCs. The minimum set is to reserve the minimum speed for each channel mapped to CCTrCH. Therefore, it retains the basic services of each channel. Since there is only one TrCH in the EU CC TrCH, the minimum set corresponds to the lowest speed per unit logical channel or the MAC-d flow mapped to the EU TrCH. The minimum set of TFCs can be one transmission block per unit TTI for each channel mapped to CCTrCH, or multiple transmission blocks per unit TTI corresponding to the GBR.

The minimum set of TFCs can be transmitted in overpowered conditions. In this situation, the WTRU shrinks all physical channels mapped to EU CCTrCH, dedicated CCTrCH, or all existing physical channels in order to keep transmit power below the maximum acceptable level.

FIG. 5 shows a block diagram of the apparatus 500 relating to the selection of TFC according to the present invention. The device includes a transmission power evaluation device 502, a TFC selection device 504, and a measurement device 506. Transmission power evaluation device 502 calculates a transmission power evaluation for each of the plurality of available TFCs. The TFC selection device 504 selects the TFC for each CCTrCH so that the sum of the evaluated WTRU transmission powers for the selected TFCs is less than or equal to the maximum value of the WTRU transmission powers. The measuring device 506 makes a physical measurement of the WTRU transmission power over a predetermined period of time. The transmission power evaluation device 502 calculates the evaluation of the transmission power of each TFC using the measurement result and the gain coefficient of the corresponding TFC.

Although the features and components of the invention are described in the above embodiments in a particular combination, each feature or component may be used alone or in the absence of the other features and components of the above embodiment. It can be used in various combinations with or without other features and components.