HK1166889A - Method and apparatus for performing uplink transmit diversity - Google Patents

Description

Method and apparatus for performing uplink transmit diversity

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No.61/160,592 filed on 3/16/2009, 61/248,241 filed on 10/2/2009, and 61/303,443 filed on 11/2/2010, which are incorporated herein by reference as if fully set forth herein.

Technical Field

The present application relates to wireless communications.

Background

A wireless transmit/receive unit (WTRU) may be equipped with receive antenna diversity. For example, certain receiver types in the third generation partnership project (3GPP) requirements may be designed with the assumption of receive diversity. Furthermore, support for downlink Multiple Input Multiple Output (MIMO) operation has been defined in technical specifications, for example in release 7(R7) of the 3GPP Wideband Code Division Multiple Access (WCDMA) Frequency Division Duplex (FDD) specification. In R7 MIMO, spatial multiplexing is achieved, for example, by two antennas at the transmitter (e.g., node B) and two antennas at the receiver (e.g., WTRU). The number of WTRUs formed with two receive antennas may increase over several years due to the potentially high data rates achievable by MIMO receivers and the increased performance that results from receive diversity alone.

However, while a WTRU may be configured with multiple antennas for receive diversity and MIMO operation, there is currently no method for a WTRU to transmit using spatial diversity. Doing so may potentially provide increased Uplink (UL) coverage, as well as provide system level gain due to lower interference. Accordingly, it would be beneficial to provide a method and apparatus for performing uplink transmit diversity.

Disclosure of Invention

A method and apparatus for performing Uplink (UL) transmit diversity in a wireless transmit/receive unit (WTRU) is disclosed. The method includes receiving a signal containing uplink precoding information. The uplink precoding information is detected and applied to UL transmission. Transmitting the UL transmission with the applied precoding weights.

Drawings

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

figure 1 illustrates an example wireless communication system including a plurality of WTRUs, a node B, a Controlling Radio Network Controller (CRNC), a Serving Radio Network Controller (SRNC), and a core network;

figure 2 is an exemplary functional block diagram of a WTRU and a node-B of the wireless communication system of figure 1;

figure 3 is an exemplary functional block diagram of a WTRU with transmit diversity;

figure 4 is an example functional block diagram of an alternative WTRU with transmit diversity;

fig. 5 shows an example fractional dedicated physical channel (F-DPCH) frame format;

fig. 6 shows an example alternative F-DPCH frame format;

fig. 7 shows an example F-DPCH frame describing an example of UL feedback bit combining;

fig. 8 shows an example F-DPCH with uplink precoding information (UPCI) pattern cycling;

fig. 9 shows an example F-DPCH with UL feedback transmitted in a single slot;

FIG. 10 shows an example frame format for signaling precoding weights in a Downlink (DL) channel; and

figure 11 shows an example encoding of an enhanced dedicated physical control channel (E-DPCCH).

Detailed Description

The term "wireless transmit/receive unit (WTRU)" as referred to below 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 user equipment capable of operating in a wireless environment. The term "base station" as referred to below 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.

Figure 1 shows a wireless communication system 100, the system 100 including a plurality of WTRUs 110, a node B120, a Controlling Radio Network Controller (CRNC)130, a Serving Radio Network Controller (SRNC)140, and a core network 150. The node B120 and the CRNC 130 may be collectively referred to as a UTRAN.

As shown in fig. 1, the WTRU 110 communicates with the node B120, and the node B120 communicates with the CRNC 130 and the SRNC 140. Although three WTRUs 110, one node B120, one CRNC 130, and one SRNC 140 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.

Figure 2 is a functional block diagram 200 of the WTRU 110 and the node-B120 of the wireless communication system 110 of figure 1. As shown in fig. 2, the WTRU 110 communicates with the node-B120 and both are configured to perform a method of uplink transmit diversity.

In addition to the components that may be found in a typical WTRU, the WTRU 110 includes a processor 115, a receiver 116, a transmitter 117, a memory 118, and an antenna 119. Memory 118 is provided to store software including operating systems, applications, and the like. The processor 115 is provided to perform the method for uplink transmit diversity alone or in combination with software. The receiver 116 and the transmitter 117 are in communication with the processor 115. The antenna 119 is in communication with both the receiver 116 and the transmitter 117 to facilitate the transmission and reception of wireless data. It may also be noted that although only one antenna 119 is shown in the WTRU 110, the WTRU 110 may utilize multiple antennas for uplink transmit diversity.

In addition to the components that may be found in a typical node B, the node B120 includes a processor 125, a receiver 126, a transmitter 127, a memory 128, and an antenna 129. The processor 125 is configured to perform a method of uplink transmit diversity. The receiver 126 and the transmitter 127 are in communication with the processor 125. The antenna 129 is in communication with both the receiver 126 and the transmitter 127 to facilitate the transmission and reception of wireless data. It may also be noted that although only one antenna 129 is shown in the node B120, multiple antennas may be utilized in the node B120 for transmission diversity.

Various methods for implementing uplink transmit diversity, e.g., spatial transmit diversity, are described herein. As described above, a WTRU 110 implementing UL transmit diversity may include multiple antennas. Thus, fig. 3 is an exemplary functional block diagram of a WTRU 300 with transmit diversity, e.g., spatial transmit diversity. The WTRU 300 includes an insertion device 310₁And 310₂Modulation/spreading device 320₁And 320₂And an antenna 330₁And 330₂. Insertion device 310₁And 310₂An input signal is received and precoding weights w1 and w2 are inserted into the signal, respectively. The precoding weight w1 may be, for example, a phase angle applied to the signal, and the precoding weight w2 may be a phase angle phase shifted from the phase of the precoding weight w 1. Modulation/spreading device 320₁And 320₂Receiving from an insertionDevice 310₁And 310₂And modulating and spreading the signal. The modulation/spreading device 320₁And 320₂Different or the same spreading codes may be used to spread and modulate their respective signals. Antenna 330₁And 330₂Receiving from modulation/spreading device 320₁And 320₂For over-the-air transmission.

Figure 4 is an example functional block diagram of an alternative WTRU 400 with transmit diversity, such as spatial transmit diversity. The WTRU 400 includes an insertion device 410₁And 410₂Modulation/spreading device 420, and antenna 430₁And 430₂. The modulation/spreading device 420 receives an input signal and modulates/spreads the signal. Insertion device 410₁And 410₂Receives the signal from the modulation/spreading device 420 and inserts precoding weights w1 and w2 into the signal, respectively. The precoding weight w1 may be, for example, a phase angle applied to the signal, and the precoding weight w2 may be a phase angle phase-shifted from the precoding weight w 1. Antenna 430₁And 430₂Receive from insertion device 410₁And 410₂For over-the-air transmission. In this alternative approach, precoding weights w1 and w2 are inserted into the signal after it is spread/modulated by modulation/spreading device 420.

To achieve transmit diversity, there are two methods that can be used, open loop transmit diversity and closed loop transmit diversity. In open-loop transmit diversity, the transmitter does not know the channel information detected at the receiver. Therefore, less control feedback is transmitted on the downlink. The WTRU referred to below may refer to WTRU 110, WTRU 300, WTRU 400, or any other type of WTRU.

In an open loop transmit diversity scheme, the WTRU may use space-time transmit diversity with a space-time block code. In addition, the Alamouti scheme can be applied at the chip level (chip level) instead of the symbol level because UL modulation cannot be either Quadrature Phase Shift Keying (QPSK) or 16 Quadrature Amplitude Modulation (QAM). This may also apply to downlink signals, such as Wideband Code Division Multiple Access (WCDMA) Frequency Division Duplex (FDD) DL signals. Joint space-time block coding with time delayed transmit diversity may also be utilized.

In an alternative approach for open loop transmit diversity, the transmit diversity may be accomplished via a hybrid automatic repeat request (HARQ) process. For example, a set of configured or predefined precoding weights may be applied to each antenna for each HARQ retransmission. The node B120 may know which precoding weight to use based on, for example, a Retransmission Sequence Number (RSN) value on the E-DPCCH, a System Frame Number (SFN), a Connection Frame Number (CFN), a subframe number, or any combination thereof.

Transmit diversity may also be accomplished in an open-loop scheme by alternating in time a set of predefined or configured precoding weights. The WTRU may then use different sets of precoding weights in a time-alternating manner, where the time unit for alternating the precoding weights may also be preconfigured or predefined, for example, as a given number of slots, TTIs, or frames. In one example, the WTRU may be configured with a set of four precoding weights. A different set of weights may be used per TTI so that the node B will know which precoding weight is being used.

In another alternative open loop transmit diversity scheme, time delayed transmit diversity may be used. For example, transmissions on one antenna may be delayed relative to transmissions on another antenna, where the time delay may be preconfigured or predefined by the network, for example. Alternatively, one set of precoding weights may be used for non-delayed transmissions and another set for time-delayed transmission signals. In addition, the precoding weights or delays may be changed from one HARQ transmission to another based on, for example, RSN, SFN, CFN, subframe number, or any combination thereof.

In contrast to the open-loop transmit diversity scheme, in the closed-loop transmit diversity scheme, the transmitter knows the channel conditions that can be detected at the receiver, or knows the precoding information that it wants to use. This knowledge may be in the form of the receiver (e.g., node-B120) sending the transmitter (e.g., WTRU) the precoding weights that node-B120 wants to use. This may be done by transmitting this information back to the receiver on the fast feedback channel. Alternatively or additionally, a transmitter (e.g., a WTRU) may utilize channel state information to determine which precoding weights to apply or use for transmission.

The preferred precoding weight information transmitted from the receiver back to the transmitter may comprise, for example, an index to a table of precoding weights. In one example, each indexed position in the table contains one or more precoding weights corresponding to one or more precoding vectors. In this example, the precoding vector may include one or more weights, constituting a weight vector w_k＝[w_k，1，w_k，2，...w_k，N]Where k is the weight vector index and N is the number of elements in the vector corresponding to the number of antennas. For the special case of two antennas, the precoding vector contains two entries (one for each antenna) w1 and w2, as described in the examples of fig. 3 and 4. In general, when multiple precoding vectors are considered, each vector k may be expressed as w_k＝[w_k，1w_k，2]. Table 1 below shows an example table containing N multi-weight vectors for a dual antenna transmit diversity system.

TABLE 1

Precoding vector index	Weight vector
		1	w1＝[w1，1，w1，2]
2	w2＝[w2，1，w2，2]
		...	...
N	wN＝[wN，1，wN，2]

In one approach to performing closed loop diversity, the feedback may be carried on, for example, the F-DPCH. A transmitter, e.g., a WTRU, receiving the feedback may re-interpret the values of the F-DPCH bits to determine which precoding weights or weight vectors to use. Fig. 5 illustrates an example F-DPCH frame format 500, which frame format 500 may be similar to a conventional F-DPCH frame format. The F-DPCH frame format 500 includes a plurality of time slots 510 (e.g., 510)₀、510₁、……、510_i、……、510₁₄). Each slot 510 includes a plurality of fields, such as a transmit offset field (Tx OFF), a Transmit Power Control (TPC) field, and another Tx OFF field. For example using time slots 510_iThe Tx OFF field 511 includes N_OFF1Bit, TPC field 512 includes N_TPCBit, and Tx OFF field 512 includes N_OFF2A bit. Table 2 below is an exemplary table of information showing exemplary F-DPCH slots 510_iInformation in the field(s).

TABLE 2

Referring now to table 2 above, F-DPCH time slot 510_iIncluding 2 bits of information per slot for TPC commands (i.e., N)_TPC2). In the example F-DPCH slot format, one of the two TPC command bits may be used to indicate the TPC command, while the other indicates which precoding to applyAnd (6) weighting. For example, if F-DPCH slot format 510_iIs "0", the first precoding weight vector (w1) may be applied, and if the second bit is "1", the second precoding weight vector (w2) may be applied. The WTRU may then apply the precoding weights in each slot while the corresponding TPC commands are applied.

In an alternative approach, the modified F-DPCH slot format may be used to inform the WTRU of the precoding weights or weight vectors that the node B expects the WTRU to use. Fig. 6 shows an alternative F-DPCH frame format 600 for such an example. The F-DPCH frame format 600 includes a plurality of time slots 610 (e.g., 610)₀、610₁、……、610_i、……、610₁₄) These slots are similar to F-DPCH format 500 and include a number of fields. For example using time slots 610_iTx OFF field 611 includes N_OFF1Bit, and Tx OFF field 612 includes N_OFF2A bit. However, field 612 is an array including N_TPCBit sum N_UPCITPC of bits and uplink precoding information (UPCI) field. Table 3 below is an example information table showing an example F-DPCH slot format 610_iInformation in the field(s).

TABLE 3

As shown in Table 3 above, N_TPCBit equal to 2, N_UPCIThe bit is equal to 0. When N is present_TPCWhen the bit is 1, then N_UPCIThe bit is 1. Thus, the WTRU may interpret a slot form such as slot form "0" as the two bits attributable to the TPC, while slot form "0A" is interpreted as the second bit attributable to the UPCI. To allow the WTRU to know which slot format is being utilized, the WTRU may be configured by the network, e.g., via RRC signaling, with the F-DPCH frame format to be used. Once configured, the WTRU may use facies while in connectionThe same F-DPCH frame format, or use the same F-DPCH frame format until a reconfiguration is received from the network.

Using the F-DPCH slot format 610 of fig. 6_iIn an alternative approach of (3), a "1" bit contained in the UPCI field may indicate a preferred precoding weight, and a "1" bit from the TPC field may be used for the TPC command. The precoding weights may be indexed by combining UPCI bits over a fixed number of F-DPCH commands or slots, which may allow indexing of more than two precoding weights or weight vectors.

For example, M consecutive UPCI bits may be combined to index 2^MOne of the predefined encoded weight vectors. With the example of M-3, the node B may signal the index of one of the 8 precoding weight vectors, which may or may not be consecutive radio slots, in 3 radio slots by transmitting the index of each of the 3 bits at a time in the UPCI field. The WTRU may then accumulate 3 UPCI bits and apply the precoding vector at the upcoming UL radio slot edge or at the predefined future UL radio slot edge. Fig. 7 shows an example F-DPCH frame 700 that depicts an example UL feedback bit combination. In fig. 7, the precoding index is shown as being contained in the UFB field of the F-DPCH and is designated, for example, as a₀a₁a₂、b₀b₁b₂、c₀c₁c₂、d₀d₁d₂And e₀e₁e₂. The WTRU then decodes and applies the precoding weights on the UL (e.g., on the DPCCH). In addition, there may be a time delay between receiving the precoding weights and the application of the precoding weights on the UL.

In another example method for performing closed-loop uplink transmit diversity, 2 bits of the F-DPCH in the TPC field may be alternated at predetermined periods to indicate TPC commands or precoding weights or weight vectors. That is, the WTRU may interpret the TPC field in some slots as TPC commands and in others over a given periodInterpreted as UPCI in the slot. Fig. 8 shows an example F-DPCH800 with a UPCI mode period. Configurable cycle length (e.g., N)_cycleOne radio slot or frame) and an offset (e.g., N for a radio slot or subframe_offset) A pattern is defined. The pattern then indicates when the TPC commands 810 are transmitted in the slot and when the UPCI 820 is transmitted. In the example shown in FIG. 8, for example, N_cycleEqual to 2 radio frames and N_offsetEqual to 26 radio time slots. Alternatively, the period length and/or offset may be expressed as a unit of time, such as milliseconds.

With continued reference to fig. 8, the slot carrying UPCI bits 820 may not carry TPC information. Because the transmitter does not receive TPC commands at that time, the transmitter may maintain the same DPCCH transmit power that was used for the slot preceding the UPCI bit 820 slot (i.e., the last TPC bit slot 810). After detecting the UPCI bits, the transmitter applies the corresponding precoding weights to the uplink transmission. The application may occur immediately upon the transmitter receiving the F-DPCH containing the UPCI or after a predefined time has elapsed after the transmitter receives the F-DPCH containing the UPCI. In one example, the application may occur at the next slot boundary.

Fig. 9 shows an example F-DPCH 900 with UL feedback transmitted in a single slot. In this example, the F-DPCH 910 includes UPCI bits detected by the transmitter in the downlink. The transmitter then applies the precoding weights in the next frame on the uplink DPCCH 920. For example, as shown in fig. 9, the transmitter is applying a precoding weight vector w_A(A) Until the UPCI bits on the F-DPCH 910 are received. At that point, the transmitter detects the UPCI bits and determines that it will use the pre-encoded weight vector w_B(B) In that respect Thus, at the beginning of the next UL DPCCH frame 920, the transmitter starts applying the precoding weight vector w_B。

In another approach to performing closed loop diversity, the feedback may be carried on another downlink physical channel. This further downlink physical channel may take a similar frame and slot format as e.g. the existing F-DPCH. In these cases, the WTRU may receive and process two F-DPCH-like channels simultaneously, one carrying TPC commands and the other carrying precoding information. This method may be used in conjunction with other methods for transmitting multiple precoded information bits described herein.

In another example method for performing closed-loop transmit diversity, precoding weights may be transmitted on an enhanced dedicated channel access grant channel (E-AGCH) subframe. The WTRU may use the transmitted precoding weights until a new E-AGCH subframe containing the new precoding weights is received. This signaling may be accomplished by re-interpreting the existing bits in the E-AGCH or by modifying the E-AGCH (e.g., by adding the UPCI field). A new high speed shared control channel (HS-SCCH) may also be used to indicate the precoding weights, where the WTRU again applies the indicated precoding weights until a new precoding weight is received. In addition, the WTRU may be configured to default (default) a set of predefined precoding weights after a predetermined period of time has elapsed after receiving the precoding weights from the node B or the network. For example, once the WTRU receives new precoding weight information (e.g., carried on the E-AGCH or HS-SCCH), the WTRU may start a timer and apply the new precoding weights. Once the timer expires, the WTRU may return to applying the predefined default precoding weights. The WTRU may reset the timer each time it receives a new precoding weight.

The precoding weights in another example may be transmitted on a downlink control channel, e.g., or similar to an E-DCH relative grant channel (E-RGCH) or an E-DCH HARQ acknowledgement indicator channel (E-HICH). Fig. 10 shows an example frame format 1000 for signaling precoding weights in a Downlink (DL) channel. The frame format 1000 includes a plurality of slots 1010 (designated as slot #0, slot #1, slot #2, slot # i, slot # 14). A bit sequence 1011 is contained in each time slot 1010. Using time slot # i (1010)_i) As an example time slot, the time slot contains a bit sequence 1010_i，0、1010_i，1、……、1010_i，39Respectively containing bit sequences b_i，0、b_i，1To b_i，39This in turn corresponds to one of 40 orthogonal sequences.

Each WTRU or group of WTRUs may be assigned one or more orthogonal sequences by the network via RRC signaling, which are multiplied or modulated with signaled precoding weights. These modulated orthogonal sequences may then be repeated over a predetermined number of slots (e.g., 3 slots of a 2ms TTI). Sequence hopping from one TTI to another TTI or from one slot to another slot within the precoding weight commands may also be applied. For example, sequence hopping for E-HIGH and E-RGCH may be used in 3GPP specification release 6. In the case of sequence hopping, the orthogonal sequence dedicated to a particular WTRU changes every 3 slots in a predefined manner.

In the case where multiple node-bs 120 or cells are part of the WTRU's active set, e.g., in a soft handover situation, each node-B120 or cell of the active set may communicate the precoding weight commands to the WTRU using any of the methods described. The WTRU may be configured to determine the best precoding weights for the UL transmission in conjunction with the precoding weight information from all node-bs 120 or cells. For example, the precoding weights [ w1, w2] may only have the value [1, 0] or [0, 1], and the WTRU may be configured to select the precoding vector for the UL transmission as the precoding weight over the majority of the node-bs 120 or cells in the active set.

Alternatively the precoding weight command may be transmitted by the serving E-DCH node B, wherein no precoding weight information is sent by other node bs or cells in the active set. In this case, the WTRU may apply precoding weight information received from the serving E-DCH node-B.

In order for the node-B120 to properly estimate the channel from both transmit antennas, the WTRU may be configured to send pilot bits from each antenna (i.e., each of the antennas 330 or 430), and these pilot bits may be weighted. Further, the node B120 may be configured to distinguish between pilots originating from each antenna. In a system such as a WCDMA FDD system, the pilot bits may be carried on a Dedicated Physical Control Channel (DPCCH).

In one example method, the DPCCH may be transmitted in an alternating manner between each antenna, where the alternating period may be predefined or configured by the network. For example, the WTRU may alternate DPCCH transmission at each slot. In another example, the alternating may be performed every TTI. Alternatively, or in addition, the alternating sequence may depend on the RSN associated with the E-DCH transmission in the same or a previous TTI.

In another example method, one DPCCH for each antenna may be transmitted and the DPCCH for the second antenna may be transmitted using a different scrambling and/or channelization code. Likewise, a new slot format for the DPCCH transmitted on the second antenna may be designed such that the new DPCCH carries only pilot bits (i.e., no TPC commands).

In another alternative, the WTRU may be configured to transmit two orthogonal pilot patterns or sequences on two UL transmit antennas. These pilot patterns may be predefined or configured by higher layers to support MIMO or TX diversity operation. For the backward capability, the primary antenna may transmit the legacy pilot pattern on the first antenna DPCCH. The second antenna may then transmit a different (optionally orthogonal) pilot pattern on the DPCCH. The TPC field on the second DPCCH may include additional pilot bits, may carry no information (i.e., Discontinuous Transmission (DTX)), or may include the same TPC information as the TPC field on the primary DPCCH.

In another alternative method for selecting precoding weights, sounding may be used. In the method, the WTRU may be configured to send a portion of its transmission using a first set of weights (e.g., w1) (f1), and a second set of weights w 2(f 2), where w1 is a vector whose number of elements corresponds to the number of antennas. In one example, part 1 is larger than part 2(f1 > f2) and the sum of the two parts is equal to 1(f1+ f2 ═ 1). For example, the WTRU may transmit with a weight w1 for 2 of the 3 slots and a weight w2 for the remaining slots. Alternatively, the WTRU transmits with a weight w1 for 3 out of 4 subframes and with a weight w2 for 1 out of 4 subframes. The use of weight patterns may be known by the base station receiver or node B120.

Depending on the fading state of the channel, one of the two sets of weights (w1 or w2) may result in more favorable reception than the other set. The base station receiver or node B120 can detect which set of weights is the best set based on knowledge of the pattern and the reception quality at a given time. Based on this information, the base station or node B120 may transmit a feedback signal, e.g., according to one of the feedback methods described above. The feedback signal may be designed in different ways.

For example, a feedback signal may be sent periodically and indicate whether the WTRUs may exchange weight sets w1 and w2, such that the best set of weights may be used during the largest part of the transmission (e.g., f 1). In another option, the feedback signal may be sent periodically and indicate which set of weights to use during portions f1 and f 2. This can be achieved using a single bit with two sets of predefined weights.

In another alternative approach, the feedback signal is only sent when the node B120 wants to command the exchange of the set of weights, so that the best set of weights can be used during the largest part of the transmission. For example, it could be a new HS-SCCH order or a special E-AGCH value using a distinct E-DCH radio network temporary identifier (E-RNTI).

The above partial weight selection can be extended to use more than 2 sets of weights. In addition, for best performance, the fraction f1 or f2 may be adjusted by higher layers according to the coherence time of the channel. It may also be beneficial to have a large partial difference (between f1 and f2) in the channel variation speed allowance.

There is also an alternative method where the WTRU may indicate to the UTRAN the precoding weights to be applied for the UL transmission. For example, an index to a list of precoding weight vectors containing individual antenna precoding weights may be signaled as part of an UL transmission. The indication may be in the form of an Uplink Precoding Weight Information (UPWI) field.

The UL DPCCH slot format may include a UPWI field or a reinterpretation of some bits in the existing UL DPCCH slot format. Table 4 below shows an example information table for the UL DPCCH slot format, where the last three rows contain the UPWI field.

TABLE 4

In this example, where the existing UL DPCCH slot format includes re-interpretation of bits to determine precoding weight information, the contents of the existing fields may be interpreted as precoding weight information. For example, slot format 5 and slot format 0 are similar to each other. Thus, in N_TFCIBits in the field may be interpreted as precoding weight information in slot 0.

In addition, a new E-DPCCH slot format including the uplink precoding weight information field may be utilized. This can again be achieved by adding a UPWI field, e.g. a 2 bit field, which can increase the code rate of the E-DPCCH. In this example, the total number of bits used to encode the E-DPCCH is increased to 12 (i.e., 7 bits for the E-TFCI, 1 happy bit, 2 bits for the RSN, and 2 bits for the UPWI). This extra 2 bits can be encoded by, for example, adding two new bases to the (32, 10) Reed-Muller code that generates the (32, 12) code.

Alternatively, the UPWI bit may be transmitted without being encoded in the E-DPCCH, or the UPWI bit may be encoded separately from the legacy E-DPCCH field. The legacy field of the E-DPCCH may be encoded using a legacy (32, 10) Reed-Muller code, but only a predefined subset (N) of the generated coded bits_E-DPCCH< 30) is transmitted. The remaining bits may be used to carry UPWI. This method allows transmission of UPWI with different protection from the legacy E-DPCCH field.

Figure 11 shows an example encoding of E-DPCCH. As shown in fig. 11, the E-TFCI, happy bit, and RSN pass through a multiplexing function 1101, a coding function (e.g., a (32, 10) Reed-Muller code) 1102, and a coded bit selection function 1103. The UPWI field is then mapped to the E-DPCCH in a new E-DPCCH physical channel mapping function 1104. For example, the mapping may be carried sequentially, i.e., all coded bits from the legacy E-DPCCH field are transmitted first, followed by bits from the UPWI field. Alternatively, the order of the mapping may be reversed. That is, bits from the UPWI field are transmitted first, followed by coded bits from the legacy E-DPCCH field. In another example, bits from the UPWI field may be interleaved with coded bits from the legacy E-DPCCH field. One example of interleaving may include transmitting one UPWI bit in each slot (e.g., during the last symbol of the radio slot).

There are other alternative methods of transmitting uplink precoding weight information from the WTRU. In one example, the uplink precoding weight information may be indicated by the WTRU through a pilot sequence transmitted on the UL DPCCH. For example, pilot sequence 1 may be used to pre-encode weight vector 1 and pilot sequence 2 may be used to pre-encode weight vector 2. Also, a new Medium Access Control (MAC) layer header element or other layer 2(L2) header information element may be used to convey the UL precoding information.

Although the features and elements of the present invention are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements 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), for execution by a general purpose computer or a processor.

For example, suitable processors include: 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 other type of 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 (RNC), 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 videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, bluetoothA module, a Frequency Modulation (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 of a Wireless Local Area Network (WLAN) module or a wireless Ultra Wide Band (UWB) module.

Examples

1. A method for performing Uplink (UL) transmit diversity implemented in a wireless transmit/receive unit (WTRU).

2. The method of embodiment 1 further comprising the WTRU transmitting pilot bits on at least one transmit antenna.

3. The method as in any one of the preceding embodiments, further comprising the WTRU receiving a signal containing uplink precoding information, wherein the uplink precoding information contains UL precoding weights.

4. The method of any of the preceding embodiments, further comprising the WTRU detecting uplink precoding information and applying the UL precoding weights to UL transmissions.

5. The method of any of the preceding embodiments, further comprising the WTRU transmitting a UL transmission with precoding weights applied.

6. The method of any preceding embodiment, wherein the precoding information comprises first precoding weights applied to a transmission on a first antenna of the WTRU.

7. The method of any of the preceding embodiments, wherein the first precoding weight is a phase angle applied to the UL transmission.

8. The method as in any one of the preceding embodiments, wherein the precoding information comprises second precoding weights applied to transmissions on a second antenna of the WTRU.

9. The method according to any of the preceding embodiments, wherein the second precoding weight is a phase shift angle of the first precoding weight applied for UL transmission on the second antenna.

10. The method of any preceding embodiment, wherein the precoding information is contained in a fractional dedicated physical channel (F-DPCH) frame slot.

11. The method according to any of the preceding embodiments, wherein the F-DPCH frame format comprises an uplink precoding information (UPCI) field containing precoding information.

12. The method as in any one of the preceding embodiments, wherein the precoding information is included in a Transmit Power Control (TPC) field of the F-DPCH.

13. The method as in any one of the preceding embodiments, wherein a Transmit Power Control (TPC) field and a UPCI field contained in the F-DPCH slot are alternated in time.

14. The method of any preceding embodiment, wherein the transmit power is applied during a UPCI field slot transmission in accordance with a TPC field transmitted before the UPCI field slot.

15. The method of any preceding embodiment, wherein the precoding information is contained in an enhanced dedicated channel access grant channel (E-AGCH) subframe.

16. The method as in any one of the preceding embodiments, further comprising the WTRU starting a timer after receiving the precoding information.

17. The method as in any one of the preceding embodiments, further comprising the WTRU applying the indicated precoding weights.

18. The method as in any one of the preceding embodiments, further comprising the WTRU applying a default precoding weight on a condition that the timer expires.

19. The method as in any one of the preceding embodiments, wherein the pilot bits are transmitted on each of a plurality of antennas using one of the following transmission techniques: transmitting a Dedicated Physical Control Channel (DPCCH) on each antenna in a time-alternating manner, transmitting one DPCCH on each antenna simultaneously using a different channelization code, and transmitting one DPCCH on each antenna simultaneously using a different pilot bit sequence.

20. The method of any preceding embodiment, wherein the DPCCH transmitted on the second antenna does not include Transmit Power Control (TPC) information.

21. The method of any of the preceding embodiments, further comprising the WTRU determining precoding weight information for application to an Uplink (UL) transmission, wherein the determined precoding information is an index to a list of precoding weight vectors.

22. The method as in any one of the preceding embodiments, further comprising the WTRU transmitting the determined precoding weight information.

23. The method of any of the preceding embodiments, further comprising the WTRU transmitting a UL transmission with precoding information applied.

24. The method of any preceding embodiment, wherein the precoding information is included in a Dedicated Physical Control Channel (DPCCH) slot format.

25. The method according to any of the preceding embodiments, wherein the DPCCH slot format comprises an Uplink Precoding Weight Information (UPWI) field containing precoding information.

26. The method of any preceding embodiment, wherein the precoding information is contained in an enhanced DPCCH (E-DPCCH) slot format.

27. A wireless transmit/receive unit (WTRU) configured to perform the method of any of the preceding embodiments.

28. The WTRU of embodiment 27 further comprising a receiver.

29. The WTRU as in any one of embodiments 27-28 further comprising a transmitter.

30. A WTRU as in any one of embodiments 27-29 further comprising a processor in communication with the receiver and/or transmitter.

31. The WTRU as in any one of embodiments 27-30 wherein the processor is configured to perform one or more of the following: transmitting pilot bits on at least one transmit antenna, receiving a signal comprising uplink precoding information, wherein the uplink precoding information comprises a UL precoding weight, detecting the uplink precoding information and applying the UL precoding weight to a UL transmission, and/or transmitting the UL transmission with the applied precoding weight.

32. The WTRU as in any one of embodiments 27-31 further comprising a first antenna and a second antenna, wherein the precoding information comprises a first precoding weight applied to the UL transmission through the first antenna and a second precoding weight applied to the UL transmission through the second antenna.

Claims (20)

1. A method for performing Uplink (UL) transmit diversity implemented in a wireless transmit/receive unit (WTRU), the method comprising:

the WTRU transmitting pilot bits on at least one transmit antenna;

the WTRU receiving a signal including uplink precoding information, wherein the uplink precoding information includes a UL precoding weight;

the WTRU detecting the uplink precoding information and applying the UL precoding weight to UL transmission; and

the WTRU transmitting the UL transmission with the applied precoding weights.

2. The method of claim 1 wherein the precoding information includes a first precoding weight applied to a transmission on a first antenna of the WTRU.

3. The method of claim 2, wherein the first precoding weight is a phase angle applied to the UL transmission.

4. The method of claim 3 wherein the precoding information includes second precoding weights applied to transmissions on a second antenna of the WTRU.

5. The method of claim 4, wherein the second precoding weight is a phase shift angle of the first precoding weight applied to the UL transmission on the second antenna.

6. The method of claim 1, wherein the precoding information is contained in a fractional dedicated physical channel (F-DPCH) frame slot.

7. The method of claim 6, wherein the F-DPCH frame format includes an uplink precoding information field (UPCI) containing the precoding information.

8. The method of claim 6, wherein the precoding information is contained in a Transmit Power Control (TPC) field of the F-DPCH.

9. The method of claim 6, wherein a Transmit Power Control (TPC) field and a UPCI field included in the F-DPCH slot are alternated in time.

10. The method of claim 9, wherein the transmit power is applied during the UPCI field slot transmission in accordance with the TPC field transmitted prior to the UPCI field slot.

11. The method of claim 1, wherein the precoding information is contained in an enhanced dedicated channel access grant channel (E-AGCH) subframe.

12. The method of claim 11, further comprising:

the WTRU starting a timer after receiving the precoding information;

the WTRU applying the indicated precoding weights; and

the WTRU applies a default precoding weight on a condition that the timer expires.

13. The method of claim 1, wherein the pilot bits are transmitted on each of a plurality of antennas using one of the following transmission techniques: transmitting a Dedicated Physical Control Channel (DPCCH) on each antenna in a time-alternating manner, transmitting one DPCCH on each antenna simultaneously using a different channelization code, and transmitting one DPCCH on each antenna simultaneously using a different pilot bit sequence.

14. The method of claim 13 wherein the DPCCH transmitted on a second antenna does not include Transmit Power Control (TPC) information.

15. A method implemented in a wireless transmit/receive unit (WTRU) of signaling precoding weight information, the method comprising:

the WTRU determining precoding weight information for application to Uplink (UL) transmissions, wherein the determined precoding information is an index to a list of precoding weight vectors;

the WTRU transmitting the determined precoding weight information; and

the WTRU transmitting a UL transmission with the applied precoding information.

16. The method of claim 15, wherein the precoding information is included in a Dedicated Physical Control Channel (DPCCH) slot format.

17. The method of claim 16 wherein the DPCCH slot format includes an Uplink Precoding Weight Information (UPWI) field containing the precoding information.

18. The method of claim 15 wherein the precoding information is contained in an enhanced DPCCH (E-DPCCH) slot format.

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

a receiver;

a transmitter; and

a processor in communication with the receiver and the transmitter, the processor configured to:

pilot bits are transmitted on at least one transmit antenna,

receiving a signal including uplink precoding information, wherein the uplink precoding information includes UL precoding weights,

detecting the uplink precoding information and applying the UL precoding weights to UL transmissions, an

Transmitting the UL transmission with the applied precoding weights.

20. The WTRU of claim 19, further comprising:

a first antenna; and

a second antenna;

wherein the precoding information includes a first precoding weight for applying to UL transmission through the first antenna and a second precoding weight for applying to UL transmission through the second antenna.