HK1171898B - A method for multiplexing data and a wireless transmit/receive unit - Google Patents

Description

Method for multiplexing data and wireless transmission/reception unit

This application is a divisional application of the chinese patent application entitled "enhanced uplink multiplexing method and apparatus" filed 5/7/2005, application No. 200580019951.2.

Technical Field

The present invention relates to a wireless communication system, and more particularly, to a method of multiplexing data and a wireless transmit/receive unit.

Background

In third generation (3G) wireless communication systems, a wireless transmit/receive unit (WTRU) has the capability to support applications that simultaneously perform multiple different quality of service (QoS) requirements. Applications for individual flows from a radio link control layer (RLC) are logical channels that are mapped to transport channels (trchs) within the Medium Access Control (MAC) layer, each TrCH being associated with a particular QoS, logical channels having similar QoS requirements being mapped to shared trchs.

Different trchs may be multiplexed into a coded composite transport channel (CCTrCH), each having a specified code rate and the code rates in the CCTrCH are matched to allow different levels of error protection. The allowed combinations of trchs in a CCTrCH transmission time interval are defined by a set of Transport Format Combinations (TFCS) that define the allowed multiplex combinations of trchs in each CCTrCH tti.

In each TTI, the MAC selects a Transport Format Combination (TFC) from the TFCS or a configured TFC subset, the TFC is selected based on the transmission priority of the logical channel mapped to each TrCH, and the TFC selection rule is based on maximizing the transmission of the highest priority data.

The TFCS is configured to allow certain TrCH data combinations but not others, and this mechanism is to ensure maximum and minimum data rates for each TrCH within the CCTrCH.

In each TTI, the TFC within the TFCS is checked to determine whether the TFC can be supported by the effective transmit power of the WTRU. TFCs that cannot be supported are considered to be in an excess power state and can be transmitted in a short period, and if the transmission power requirements cannot be met during this period, the TFCs are blocked from transmission and some TFCs in the "minimum set" are not blocked. The transport channel configuration, TFC selection rules, and the minimum set of TFCS are used to maintain QoS for individual data streams.

Enhanced Uplink (EU) has been developed to reduce transmission latency in the uplink and increase radio resource efficiency. A WTRU provides only one EUTrCH, and since each WTRU has only one EUTrCH, there is only one Transport Format (TF) table for the EUTrCH that does not distinguish between different logical channel priorities and QoS requirements, the configured CCTrCHTFCS and TFC selection rules properly coordinate transport multiplexing within a TTI, useful only when logical channels that provide multiple trchs and share QoS requirements are mapped to a particular TrCH. With only one EUTrCH, these multiplexing rules and the QoS provided to individual data streams are not valid for the EU.

In order to properly maintain the QoS requirements of individual data flows, it is therefore necessary to define new WTRU multiplexing rules for logical channels or MAC-d flows mapped to enhanced uplink medium access control (MAC-e) Protocol Data Units (PDUs).

Disclosure of Invention

The present invention is a method and apparatus for enhanced uplink multiplexing. A set of combinations of MAC-d flows (and/or logical channels) is defined for each WTRU that are allowed to be multiplexed within a MAC-e pdu. The wtru MAC-e entity selects for each MAC-e pdu a combination from a set of allowed combinations of multiplexed MAC-d flows. It may be defined that certain logical channels or corresponding MAC-d flow combinations cannot be blocked from transmission even when the WTRU is in a transmit power limited state. The amount of data from each logical channel or corresponding MAC-d flow that can be multiplexed within a MAC-e pdu may be defined to ensure a certain data rate. When the WTRU is in a restricted power state, which reduces the EU transmission load below that allowed by the EU channel assignment received from the node-B, an indication of the restricted power state may be passed to the node-B for the EU transmission.

The invention provides a method for multiplexing data, which comprises the following steps: receiving data on a plurality of logical channels; multiplexing data from the plurality of logical channels into Medium Access Control (MAC) Protocol Data Units (PDUs) based on a priority associated with each of the plurality of logical channels; and transmitting the MACPDU over an uplink transport channel.

The present invention also provides a wireless transmit/receive unit (WTRU) comprising: means for receiving data on a plurality of logical channels; means for multiplexing data from a plurality of logical channels into a Medium Access Control (MAC) Protocol Data Unit (PDU) based on a priority associated with each of the plurality of logical channels; and means for transmitting the mac pdu on an uplink transport channel.

The present invention also provides a method of multiplexing data, the method comprising: receiving configuration information from the wireless network, wherein the configuration information indicates a priority of each logical channel; determining a data size based on the configuration information; multiplexing data of the logical channels into Medium Access Control (MAC) Protocol Data Units (PDUs) based on the priorities and the determined data sizes; and transmitting the mac pdu to the wireless network.

The present invention also provides a wireless transmit/receive unit (WTRU) comprising: means for receiving configuration information from a wireless network; wherein the configuration information indicates a priority of each logical channel; means for determining a data size based on the configuration information; means for multiplexing data of the logical channels into Medium Access Control (MAC) Protocol Data Units (PDUs) based on the priorities and the determined data sizes; and means for transmitting the mac pdu to the wireless network.

Drawings

The invention will be understood in more detail from the following description of a preferred embodiment, given as an example, and with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a WTRU for EU multiplexing according to the present invention;

FIG. 2 is a flowchart of a procedure for EU multiplexing according to the present invention; and

FIG. 3 is a block diagram of a WTRU MAC-e entity including functional blocks in addition to control signals according to one embodiment of the present invention.

Detailed Description

Hereinafter, the term "WTRU" includes, but is not limited to, a user equipment, a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the terminology "node B" includes but is not limited to a base station, a site controller, an access point, or any type of interfacing device in a wireless environment.

Figure 1 is a block diagram of a WTRU100 for EU multiplexing according to the present invention. The WTRU includes an RLC layer 102, a MAC-d entity 104, a MAC-e entity 106, and a PHY entity 108. The RLC layer 102, the MAC-d entity 104 and the PHY entity 108 perform similar functions of WTRUs in existing wireless communication systems. It is noted that the configuration shown in fig. 1 is provided as an example, and the functions performed by the MAC-d and MAC-e entities may be combined into one entity, and the functions of the entities in fig. 1 may be implemented in more or less functional entities.

The RLC layer 102 includes one or more RLC entities, each associated with a particular logical channel, such as a Dedicated Control Channel (DCCH) or a Dedicated Traffic Channel (DTCH). Each MAC-d flow has its associated QoS attributes. The MAC-e entity 106 includes a multiplexing function 106a and an EUTFC selection function 106 b. The MAC-E entity multiplexes the MAC-d flow to a MAC-E pdu while selecting an appropriate TF for an enhanced uplink dedicated channel (E-DCH). The PHY entity 108 processes the MAC-e pdus for wireless transmission.

The WTRU100 is configured to support EU transmission over a single EUTrCH. According to the present invention, an allowed combination of a set of MAC-d flows (and/or logical channels), which are allowed to be multiplexed within a MAC-e pdu, is defined for each WTRU 100. MAC-e pdu multiplexing rules are defined that describe which data is selected from the MAC-d flows (and/or logical channels) and multiplexed to the MAC-e pdus to maintain QoS requirements. The rules may be predefined by a standard or signaled to the WTRU100 by a Radio Network Controller (RNC) through a Radio Resource Control (RRC) procedure. The RRC sending the combined set provides the RNC with the ability to control the logical channels or corresponding MAC-d flows to achieve their specific QoS requirements.

Certain MAC-d flow (and/or logical channel) combinations that are not blocked from transmission even when the WTRU is in a transmit power limited state may be defined to avoid blocking of any MAC-d flow (and/or logical channel). These combined transmissions may also be allowed without EU transmission assignments from the node bs.

According to an embodiment of the present invention, the number of PDUs per Transmission Time Interval (TTI) from each MAC-d flow (and/or logical channel) can be multiplexed within the MAC-e PDU. The number of PDUs per TTI represents the data rate of each channel, for example, all allowed combinations may include one or more PDUs from a particular logical channel, which will ensure that this particular logical channel is always served.

According to another embodiment of the present invention, the combining set may be defined by a specific data rate from each MAC-d flow (and/or logical channel) that may be multiplexed into the MAC-e pdu, or may be defined by a specific data rate in combination with/or without the specific data rate of other MAC-d flows (and/or logical channels). The data rate from each MAC-d flow (and/or logical channel) may be explicitly matched to the data rates of other MAC-d flows (and/or logical channels), which may not transmit data in some combinations. Combining may also identify possible rates for each MAC-d flow (and/or logical channel) and allow the WTRU to select any known rate from other channels that does not exceed the assigned physical channel or transmit power limit.

Within the set of allowable combinations, absolute or relative priority multiplexing rules may be defined to maintain proper prioritization among MAC-d flows (and/or logical channels). According to the absolute priority scheme, higher priority logical channels or MAC-d flows are always served before lower priority logical channels or MAC-d flows, and the selected multiplex combination is to support the highest priority data in the TF set defined for the EUTrCH.

Alternatively, the logical channel or MAC-d flow combination configured by the RRC signaling procedure that can be configured within the MAC-e pdu or allowed combination of MAC-d flows may be preferred over absolute priority, the core network may also describe the data size or number of MAC-d pdus that are allowed to be multiplexed by each logical channel or MAC-d flow to each MAC-e pdu.

According to the relative priority scheme, a weighting scheme is described to appropriately service low priority channels, which defines a weight for each MAC-d flow (and/or logical channel), and the available bandwidth on the E-DCH is allocated to each logical channel or MAC-d flow according to the defined weight. This method allows data rates to be allocated on logical channels or corresponding MAC-d flows and avoids bandwidth starvation of low priority channels.

The allowed combination set may be explicitly signaled by the RRC procedure, which configuration allows the RNC to control WTRU multiplexing selection, which is unique to Radio Access Bearer (RAB) requirements. The specific allowed combination of logical channels or MAC-d flows is configured to multiplex the processing at each MAC-e pdu.

In each EUTTI, the WTRU continuously monitors the status of allowed combinations of MAC-d flows (and/or logical channels) and selects an appropriate transmission combination according to the monitored status. If the transmission power requirement of a particular combination exceeds the remaining power requirement for allowing wtru E-DCH transmission, the combination is in an excess power state and the combination is blocked by E-TFC selection. Detecting and blocking the transmission time of the MAC-d flow (and/or logical channel) combination may require several E-DCHTTIs. When the transmission power is sufficient, a similar mechanism is used to return the combination to the allowed combination set.

Certain MAC-d flow (and/or logical channel) combinations that do not block transmission even when the WTRU is in a transmit power limited state may be defined to avoid blocking of any MAC-d flow (and/or logical channel), and transmission of these combinations may be allowed without EU channel assignment from the node-B. Since there is only one EUTrCH, no TFC set is defined for multiple trchs, and only one TF table is defined for a single EUTrCH, it is necessary to define the MAC-d flow (and/or logical channel) combinations in a minimum set, which is not blocked. For example, the minimum set of E-DCH may be defined such that at least one MAC-d pdu may always be transmitted from any MAC-d flow or logical channel, even when the remaining power available for E-DCH is limited.

The rules for multiplexing MAC-d flows (and/or logical channels) to MAC-e pdus per TTI may include combinations per MAC-d flow (and/or logical channel) that include the smallest possible load for a logical channel or MAC-d flow, and no data for other logical channels or MAC-d flows mapped to the EUTrCH, which may be defined as the minimum set that can be a signaling radio bearer to ensure signaling to the node B in a power limited state.

Under current 3GPP standards, TFCs are allocated to each TrCH that provide the smallest possible transmission on one TrCH and no data transmission on other trchs within the CCTrCH, which are always allowed to be transmitted to avoid the possibility of blocking individual channels. In the case of EU with only one TrCH supporting multiple logical channels or MAC-d flows, a single reserved TFC is not sufficient. For EUTrCH, several EUTF or TFCs are required to support the minimum set of multiplexing combinations. EUTF or TFC includes a configuration that allows the transmission of the least possible load of a logical channel or MAC-d flow.

When the WTRU is in a restricted power state that reduces the EU transmission load below that allowed by the EU channel assignment received from the node-B, an indication of the restricted power state is communicated to the node-B with the EU transmission. The indication may be explicitly sent by a signaling message (e.g., a new information unit) that the WTRU may inform the WTRU of the level of available transmit power.

The node-B may determine without error whether the WTRU is in a power limited state, which the node-B may detect by comparing the channel assignment sent to the WTRU with the corresponding transmission received from the WTRU. If the channel assignment exceeds transmission and the WTRU continues to transmit at a reduced rate or indicates that it has more data to send, the node-B detects the WTRU power restriction state and takes appropriate action.

FIG. 2 is a flow chart of a process 200 for EU multiplexing according to the present invention. The WTRU is configured to support EU transmission over a single EUTrCH. A set of allowed combinations of MAC-d flows (and/or logical channels) is first defined for each WTRU, which allows multiplexing to one MAC-e pdu (step 202). The transmitted data is processed by at least one RLC entity in the RLC layer and forwarded to a MAC-d entity via at least one logical channel (step 204). The transmission data is mapped onto one or more MAC-d flows at the MAC-d entity (step 206), each MAC-d flow being associated with a particular QoS attribute. A combination of MAC-d flows (and/or logical channels) is selected from the allowed combination set (step 208). Data from the MAC-d flow is multiplexed into the MAC-e pdu according to the selected combination (step 210). The MAC-e pdu is forwarded to the physical layer via the EUTrCH for physical layer processing (step 212).

FIG. 3 is a block diagram of an embodiment of a WTRU MAC-e entity 1-6 including functional blocks in addition to control signals in accordance with the present invention. While three functional blocks are shown in fig. 3, the arrangement shown in fig. 3 is provided as an example, and it is noted that other arrangements may be implemented, which may be combined or separated with more or fewer functional blocks, which may be in a different order, and which may be performed concurrently or sequentially, without departing from the scope of the present invention.

Data from a logical channel or corresponding MAC-d flow enters the first functional block 106 of the MAC-e entity 106₁The first function block 106₁From the allowed combinations of MAC-d flows (and/or logical channels), a subset of MAC-d flow (and/or logical channel) combinations is determined. Optionally, the first function block 106₁The possible rate for each MAC-d flow (and/or logical channel) may be determined based on the RRC configuration.

Second function Block 106₂The effective power and E-TFC are determined for a subset of MAC-d flow (and/or logical channel) combinations, and the effective power of E-DCH can also be a configurable parameter. Optionally, a second functional block 106₂The E-TFC may be decided based on a combined minimum set of transmissions that cannot be blocked.

Third function Block 106₃The MAC-e pdus are generated according to a preset criterion to multiplex the MAC-d flows, e.g. configure logical channels or MAC-d flow priorities to maximize the transmission of the highest priority data.

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

Claims (20)

1. A method of multiplexing data, the method comprising:

receiving data on a plurality of logical channels, each logical channel associated with a quality of service (QoS) requirement;

multiplexing data from the plurality of logical channels into enhanced medium access control (MAC-e) Protocol Data Units (PDUs) to maintain QoS requirements of the logical channels based on a priority associated with each of the plurality of logical channels; and

transmitting the MAC-ePDU on an uplink transport channel.

2. The method of claim 1, wherein data from the plurality of logical channels is multiplexed based on an associated priority.

3. The method of claim 1, wherein each of the plurality of logical channels is associated with an allowed data rate.

4. The method of claim 3, wherein data from the plurality of logical channels is multiplexed based on the allowed data rate and a priority associated with each of the plurality of logical channels.

5. The method of claim 3, wherein data from a logical channel associated with a highest priority is multiplexed to earliest reach the allowed data rate associated with the highest priority logical channel.

6. The method of claim 3, wherein data from a logical channel associated with a higher priority is multiplexed to its allowed data rate before data from a logical channel associated with a lower priority is multiplexed.

7. The method of claim 3, wherein the allowed data rate is received from a radio network.

8. A wireless transmit/receive unit (WTRU) comprising:

means for receiving data on a plurality of logical channels, each logical channel associated with a quality of service (QoS) requirement;

means for multiplexing data from the plurality of logical channels into enhanced medium access control (MAC-e) Protocol Data Units (PDUs) to maintain QoS requirements of the logical channels based on a priority associated with each of the plurality of logical channels; and

means for transmitting the MAC-ePDU on an uplink transport channel.

9. The WTRU of claim 8, wherein data from the plurality of logical channels is multiplexed based on associated priorities.

10. The WTRU of claim 8, wherein each of the plurality of logical channels is associated with an allowed data rate.

11. The WTRU of claim 10, wherein data from the plurality of logical channels is multiplexed based on the allowed data rate and a priority associated with each of the plurality of logical channels.

12. The WTRU of claim 10, wherein data from a logical channel associated with a highest priority is multiplexed to earliest achieve the allowed data rate associated with the highest priority logical channel.

13. The WTRU of claim 10 wherein data from a logical channel associated with a higher priority is multiplexed to its allowed data rate before data from a logical channel associated with a lower priority is multiplexed.

14. The WTRU of claim 10, wherein the allowed data rate is received from a radio network.

15. A method of multiplexing data, the method comprising:

receiving configuration information from a wireless network, wherein the configuration information indicates a priority of each of a plurality of logical channels;

determining a data size based on the configuration information;

multiplexing data of the logical channel into enhanced media access control (MAC-e) Protocol Data Units (PDUs) to maintain QoS requirements of the logical channel based on the priority and the determined data size; and

transmitting the MAC-ePDU to the wireless network.

16. The method of claim 15, wherein the data of the logical channels is multiplexed in order from the highest priority logical channel to the lowest priority logical channel.

17. The method of claim 15, wherein data of a highest priority logical channel is multiplexed based on the determined data size before multiplexing a next highest priority logical channel.

18. A wireless transmit/receive unit (WTRU) comprising:

means for receiving configuration information from a wireless network, wherein the configuration information indicates a priority for each of a plurality of logical channels;

means for determining a data size based on the configuration information;

means for multiplexing data of the logical channel into enhanced medium access control (MAC-e) Protocol Data Units (PDUs) to maintain QoS requirements of the logical channel based on the priority and the determined data size; and

means for transmitting the MAC-ePDU to the wireless network.

19. The WTRU of claim 18 wherein data for the logical channels is multiplexed in an order from a highest priority logical channel to a lowest priority logical channel.

20. The WTRU of claim 18, wherein data of a highest priority logical channel is multiplexed based on the determined data size before multiplexing a next highest priority logical channel.