HK1179782B - A method and apparatus for wireless communication - Google Patents

Description

Method and device for wireless communication

The present application is a divisional application of chinese patent application entitled "pilot structure for ACK and CQI in wireless communication system" with an application date of 2008/5/15 and an application number of 200880016601.4.

The present application claims priority from U.S. provisional application No.60/938,995 entitled "a METHOD AND APPARATUS FOR UPLINK CONTROL CHANNEL MULTIPLEXING AND POWER CONTROL", filed on day 18, 5/2007, which is assigned to the assignee of the present application AND is hereby expressly incorporated herein by reference.

Technical Field

The present disclosure relates generally to communication, and more specifically to techniques for transmitting data and pilot for control information in a wireless communication system.

Background

Wireless communication systems have been widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, and so on. These wireless systems are multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and single-carrier FDMA (SC-FDMA) systems.

In a wireless communication system, a node B may transmit traffic data to a User Equipment (UE) on a downlink and/or receive traffic data from the UE on an uplink. The downlink (or forward link) refers to the communication link from the node bs (node bs) to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the node bs. The UE may send Channel Quality Indicator (CQI) information to the node B indicating the downlink channel quality. The node B may select a rate or a transport format according to the CQI information and may transmit traffic data to the UE at the selected rate or transport format. The UE may send Acknowledgement (ACK) information for traffic data received from the node B. The node B may determine whether to retransmit the unfinished traffic data or transmit new traffic data to the UE according to the ACK information. To achieve good performance, ACK and CQI information needs to be reliably transmitted.

Disclosure of Invention

Techniques for transmitting data and pilot for ACK, CQI, and other control information in a wireless communication system are described herein. In an aspect, data and pilot for control information (e.g., ACK information) may be sent with Code Division Multiplexing (CDM) in frequency and time domains. In one design, a UE may be assigned a reference signal sequence selected from a set of reference signal sequences generated based on different cyclic shifts of a base sequence. These reference signal sequences have good correlation properties and can be sent simultaneously by different UEs on the same set of subcarriers in the same symbol period. A first orthogonal sequence selected from a set of orthogonal sequences generated based on a Discrete Fourier Transform (DFT) matrix or a Walsh matrix may also be allocated to the UE. The UE may use the first orthogonal sequence to broaden the reference sequence to obtain multiple pilot sequences. The UE may then transmit the plurality of pilot sequences on a plurality of subcarriers in a plurality of symbol periods, one pilot sequence in each symbol period. A second orthogonal sequence of a set of orthogonal sequences for data may also be assigned to the UE. The UE may modulate the reference signal sequence with the ACK information to obtain a modulated sequence. The UE may then broaden the modulation sequence with the second orthogonal sequence to obtain a plurality of data sequences. The UE may transmit the plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data.

In another aspect, data and pilot for control information may be sent with frequency-domain CDM and pilot distributed over time. In one design, a UE may be assigned a reference signal sequence and may generate multiple pilot sequences based on the reference signal sequence. The UE may transmit the plurality of pilot sequences on a plurality of subcarriers in a plurality of symbol periods separated by at least one symbol period, one pilot sequence in each symbol period. The UE may also generate a plurality of modulation symbols based on control information (e.g., CQI information only or CQI and ACK information). The UE may modulate the reference signal sequence with the plurality of modulation symbols to obtain a plurality of data sequences. The UE may then transmit the plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data.

As described below, the node B may receive data and pilot sequences from different UEs and perform complementary processing procedures to recover the control information transmitted by each UE. Various aspects and features of the disclosure are further described below.

Drawings

Fig. 1 shows a wireless communication system.

Fig. 2 shows an example transmission structure of an uplink.

Fig. 3A and 3B show two designs of ACK structure.

Fig. 4 shows a design of a CQI structure.

Fig. 5 shows a block diagram of a node B and a UE.

Fig. 6 shows a block diagram of a sending processor of the ACK.

Fig. 7 shows a block diagram of a transmission processor of CQI.

Fig. 8 shows a block diagram of an SC-FDM modulator.

Fig. 9 shows a block diagram of an SC-FDM demodulator.

Fig. 10 shows a block diagram of a reception processor of ACK.

Fig. 11 shows a block diagram of a reception processor of CQI.

Fig. 12 shows a process for transmitting data and pilot for ACK.

Fig. 13 shows an apparatus for transmitting data and pilot for ACK.

Fig. 14 shows a process for transmitting data and pilot for CQI.

Fig. 15 shows an apparatus for transmitting data and pilot for CQI.

Fig. 16 shows a process for receiving ACK.

Fig. 17 shows an apparatus for receiving an ACK.

Fig. 18 shows a process for receiving CQI.

Fig. 19 shows an apparatus for receiving CQI.

Fig. 20 shows a process for supporting transmission of ACKs and CQIs.

Fig. 21 illustrates an apparatus for supporting transmission of ACKs and CQIs.

Detailed Description

The techniques described herein may be used for various wireless communication systems, such as: CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes wideband-CDMA (W-CDMA) and other CDMA variants. Further, cdma2000 covers IS-2000, IS-95 and IS-856 standards. TDMA systems may implement wireless technologies such as global system for mobile communications (GSM). OFDMA systems may implement, for example, evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and,Etc. wireless technologies. UTRA and E-UTRA are global mobile phonesPart of a telecommunications system (UMTS). 3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from an organization named "third Generation Partnership Project" (3 GPP). In addition, cdma2000 and UMB are described in files from an organization named "third Generation Partnership Project2 (3 rd Generation Partnership Project 2)" (3 GPP 2). For clarity, certain aspects of these techniques are described below for LTE, and the terminology of LTE is used in much of the description below.

Fig. 1 illustrates a wireless communication system 100 with multiple node bs 110. A node B may be a fixed station that communicates with UEs and may also be referred to as an evolved node B (enb), a base station, an access point, etc. The UEs 120 may be distributed throughout the system, and each UE may be fixed or mobile. A UE may also be called a mobile station, terminal, access terminal, subscriber unit, station, etc. The UE may be a cellular phone, a Personal Digital Assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop, a cordless phone, and so on. A UE may communicate with a node B via transmissions on the downlink and uplink.

Fig. 2 shows a design of a transmission structure 200 that may be used for the uplink. The transmission timeline may be divided into subframe units. The subframe has a predetermined duration, e.g., 1 millisecond (ms), and may be divided into two slots. Each slot includes a fixed or configurable number of symbol periods, e.g., six symbol periods in the case of an extended cyclic prefix and seven symbol periods in the case of a normal cyclic prefix.

For the uplink, a total of K subcarriers are available and may be grouped into resource blocks. Each resource block includes N subcarriers (e.g., N =12 subcarriers) in one slot. The available resource blocks may be divided into a data portion and a control portion. The control portion is formed at both edges of the system bandwidth as shown in fig. 2. The control section has a configurable size that can be selected based on the amount of control information sent by the UE on the uplink. The resource blocks in the control portion may be allocated to the UE for transmission of ACK information, CQI information, and the like. The data section includes all resource blocks not included in the control section. The design in fig. 2 is such that contiguous subcarriers are included in the data portion, which makes it possible to allocate all of the contiguous subcarriers in the data portion to a single UE.

The UE may be assigned resource blocks in the control portion to send ACK and/or CQI information to the node B. The ACK information may convey: whether each transport block sent by the node B to the UE is decoded correctly or in error by the UE. The amount of ACK information to be sent by the UE depends on the number of transport blocks sent to the UE. In one design, the ACK information may include one or two ACK bits depending on whether one or two transport blocks are sent to the UE. In other designs, the ACK information may include more ACK bits.

The CQI information may convey the downlink channel quality estimated by the UE for the node B. The amount of CQI information sent by the UE depends on various factors, such as: the number of spatial channels available for downlink transmission, the format used to report the downlink channel quality, the granularity needed in the reported downlink channel quality, etc. In one design, the CQI information may include 8,9, or 10 bits. In other designs, the CQI information may include fewer or more bits.

The UE may send ACK and/or CQI information on a Physical Uplink Control Channel (PUCCH), which may be mapped to resource blocks in the control portion. In one design, two PUCCH structures may be supported and may be referred to as an ACK structure and a CQI structure. The ACK structure is used only for sending ACK information. The CQI structure may be used only for transmitting CQI information or may be used for transmitting ACK and CQI information. The ACK and CQI structure may also be referred to by other names. For example, the ACK structure may also be referred to as PUCCH format 0 or 1 depending on whether one or two ACK bits are transmitted. The CQI structure may also be referred to as PUCCH format 2.

Table 1 lists some characteristics of the ACK and CQI structures consistent with one design. Table 1 shows the number of symbol periods for data and the number of symbol periods for pilot in one slot having seven symbol periods. Pilots are data known to both the transmitter and the receiver in advance and may be referred to as references, preambles, and the like.

TABLE 1-PUCCH structure

Spreading refers to the following process: the symbols are first replicated to obtain multiple replicas, which are then multiplied by orthogonal sequences to obtain multiple spread symbols. Multiple UEs may transmit symbols simultaneously on the same resource with different orthogonal sequences. The node B may recover the symbols transmitted by the UEs by performing complementary despreading (despreading) processes. Widening is also commonly referred to as masking.

Fig. 3A shows a design of an ACK structure 300 for the case where each slot includes seven symbol periods. In each subframe, the left slot includes seven symbol periods 0 to 6, and the right slot includes seven symbol periods 7 to 13. One or more UEs may simultaneously send ACK information on a resource block pair, the resource block pair comprising: (i) one resource block in the top control section in the left slot and one resource block in the bottom control section in the right slot, as shown in fig. 3A; or (ii) one resource block in the bottom control section in the left slot and one resource block in the top control section in the right slot (shown with diagonal lines in fig. 3A).

In one design, a resource block for ACK may include four symbol periods for data and three symbol periods for pilot. In the design shown in fig. 3A, pilot is sent in the middle three symbol periods of a resource block, and data is sent in the remaining four symbol periods. The data and pilot for the ACK may also be sent in other symbol periods in the resource block.

In one design, the UE may send the data and pilot for the ACK using a reference signal sequence with good correlation properties. Different UEs may send data and pilot for the ACK on the same resource block with different reference signal sequences, which may be generated with a base sequence. In one design, the base sequence may be a CAZAC (constant amplitude zero auto-correlation) sequence, such as a Chu sequence, a Zardoff-Chu sequence, a Frank sequence, a generalized chirp-like (GCL) sequence, and so forth. In another design, the base sequence may be a sequence defined to have good correlation properties.

In one design, multiple reference signal sequences of length N may be generated with different cyclic shifts of a base sequence of length N, as follows:

r_α(n)＝r_b((n+α)mod N)＝e^jαn·r_b(N) wherein N is 0,1, N-1 formula (1)

Wherein r is_b(n) is a base sequence, n is an index of a symbol;

r_α(n) is a reference signal sequence with a cyclic shift α;

"mod" denotes a modulo operation.

In one design, N =12 and each reference signal sequence is 12 in length. Six reference signal sequences may be generated with six different alpha values and assigned to different UEs. The multiple reference signal sequences may also be generated in other ways.

In one design, the UE may use a single reference signal sequence for all symbol periods of a subframe. In another design. The UE can be used for acupunctureDifferent reference signal sequences are used for different symbol periods of the subframe. In another design, the UE may use different reference signal sequences for different slots of a subframe. In the latter two designs, hopping can randomize interference. For simplicity, the following description assumes that the UE uses a single reference signal sequence r (n) for all symbol periods, where for a specific value of α: r (n) ═ r_α(n)。

In one design, the UE may broaden its pilot for ACK with an orthogonal sequence assigned to it. For the design shown in fig. 3A, an orthogonal sequence of length 3 may be used to transmit pilots in three symbol periods. In one design, DFT matrix D is based on 3 × 3_3×3To define three orthogonal sequences, the matrix is represented as:

formula (2)

Three orthogonal sequences q may be defined by three rows in a 3 x 3 DFT matrix₀(m)、q₁(m) and q₂(m), these three sequences can be represented as:

q₀(m)＝[111]formula (3a)

q₁(m)＝[1e^j2π/3 e^j4π/3]Formula (3b)

q₂(m)＝[1^ej4π/3 e^j2π/3]Formula (3c)

Where m is the index of the symbol period.

In general, the length and number of orthogonal sequences used for pilots depends on the number of symbol periods used for pilots. For example, two orthogonal sequences of length 2 may be used for pilots transmitted in two symbol periods, four orthogonal sequences of length 4 may be used for pilots transmitted in four symbol periods, and so on. There are different types of orthogonal sequences available for different lengths. For example, orthogonal sequences of arbitrary length M may be defined from an M × M DFT matrix, while orthogonal sequences of length powers of 2 (e.g., 2, 4, etc.) may be defined from a Walsh (Walsh) matrix.

In one design, the UE may generate a pilot for the ACK as follows:

p_m(N) ═ q (m) · r (N) where N ═ 0.., N-1 and m ═ 0,1,2 formula (4)

Wherein q (m) is an orthogonal sequence for pilot allocated to the UE;

p_m(n) is the pilot sequence for ACK for symbol period m.

The orthogonal sequence q (m) assigned to the UE may be q₀(m)、q₁(m) or q₂(m) of the reaction mixture. In the design shown in equation (4), each of the N symbols of the reference signal sequence r (N) is multiplied by the first symbol q (0) in the orthogonal sequence to obtain the first pilot sequence p₀(n) multiplying the second symbol q (1) in the orthogonal sequence to obtain a second pilot sequence p₁(n) and multiplied by a third symbol q (2) in the orthogonal sequence to obtain a third pilot sequence p₂(n) of (a). The three pilot sequences p may be transmitted in three symbol periods 2, 3 and 4 in the left slot and also in three symbol periods 9, 10 and 11 in the right slot₀(n)、p₁(n)、p₂(n) as shown in FIG. 3A.

A maximum of 18 UEs may use six reference signal sequences and three orthogonal sequences q₀(m)、q₁(m) or q₂(m) pilot for ACK is sent simultaneously. Each UE transmits its pilot with a designated reference signal sequence r (n) and a designated orthogonal sequence q (m). The pilots from these UEs may be distinguished by (i) spreading in the time domain with orthogonal sequences and (ii) differentiation of the reference signal sequences in the frequency domain.

In one design, the UE may spread its data for the ACK with an orthogonal sequence assigned to it. For the design shown in fig. 3A, an orthogonal sequence of length 4 may be used to transmit data in four symbol periods. In one design, four orthogonal sequences are defined based on a 4 × 4 walsh matrix W4 × 4, which may be expressed as:

formula (5)

Four orthogonal sequences w may be defined by four rows of the 4 x 4 walsh matrix₀(m),w₁(m),w₂(m) and w₃(m), which can be expressed as:

w₀(m)＝[+1+1+1+1]formula (6a)

w₁(m)＝[+1-1+1-1]Formula (6b)

w₂(m)＝[+1+1-1-1]Formula (6c)

w₃(m)＝[+1-1-1+1]Formula (6d)

In general, the length and number of orthogonal sequences used for data depends on the number of symbol periods used for data. For example, three orthogonal sequences of length 3 may be used for data transmitted in three symbol periods, and so on.

In one design, the UE may process the data for the ACK in a manner described below. The UE first maps one or two bits of the ACK to a modulation symbol d (0) according to BPSK or QPSK, respectively. Then, the UE modulates its reference signal sequence r (n) with modulation symbol d (0), as follows:

y (N) ═ d (0) · r (N) where N ═ 0.., N-1 equation (7)

Where y (n) is the modulation sequence for ACK. As shown in equation (7), the same modulation symbol may be applied to each of the N symbols of the reference signal sequence.

Then, the UE broadens the modulation sequence by:

z_m(N) ═ w (m) y (N) where N is 0,.., N-1 and m is 0

Where w (m) is an orthogonal sequence for data allocated to the UE;

z_m(n) is the data sequence for ACK for symbol period m.

The orthogonal sequence assigned to the UE, w (m), may be w₀(m)、w₁(m)、w₂(m) or w₃(m) of the reaction mixture. In the design shown in equation (8), each of the N symbols of the modulation sequence y (N) may be multiplied by the first symbol w (0) in the orthogonal sequence to obtain the first data sequence z₀(n) multiplying by a second symbol w (1) in the orthogonal sequence to obtain second dataSequence z₁(n) multiplied by a third symbol w (2) in the orthogonal sequence to obtain a third data sequence z₂(n) and multiplied by a fourth symbol w (3) in the orthogonal sequence to obtain a fourth data sequence z₃(n) of (a). As shown in fig. 3A, four data sequences z may be transmitted in four symbol periods 0,1, 5 and 6 in the left slot and also in four symbol periods 7, 8, 12 and 13 in the right slot₀(n)、z₁(n)、z₂(n) and z₃(n)。

A maximum of 24 UEs may use six reference signal sequences and four orthogonal sequences w₀(m) to w₃(m) simultaneously transmitting data of the ACK. Each UE may transmit its data with a designated reference signal sequence r (n) and a designated orthogonal sequence w (m). The data from these UEs may be distinguished by (i) spreading in the time domain with orthogonal sequences and (ii) differentiation of the reference signal sequences in the frequency domain.

In one design, 18 ACK channels may be defined with six reference signal sequences, three orthogonal sequences for pilot, and four orthogonal sequences for data. The number of ACK channels is limited to the number of UEs that can send pilots simultaneously. Each ACK channel is associated with a designated reference signal sequence r (n), a designated orthogonal sequence q (m) for pilot, and a designated orthogonal sequence w (m) for data. Up to 18 UEs may send their ACK information simultaneously on up to 18 ACK channels on the same resource block pair.

Fig. 3B shows a design of an ACK structure 310 for the case where each slot includes six symbol periods. In each subframe, the left slot includes six symbol periods 0 to 5, and the right slot includes six symbol periods 6 to 11. In one design, a resource block for ACK may include four symbol periods for data and two symbol periods for pilot. In the design shown in fig. 3B, pilot is sent in the middle two symbol periods of a resource block, and data is sent in the remaining four symbol periods. The data and pilot for the ACK may also be sent in other symbol periods in the resource block.

In one design, DFT matrix D is based on 2 × 2_2×2Two orthogonal sequences of length 2 are defined for the pilot, and the matrix can be expressed as:

formula (9)

The 2 x 2 DFT matrix is equal to the 2 x 2 walsh matrix.

Two orthogonal sequences q may be defined by two rows of a2 x 2 DFT matrix₀(m) and q₁(m), and can be expressed as:

q₀(m)＝[+1+1]formula (10a)

q₁(m)＝[+1-1]Formula (10b)

For the design shown in fig. 3B, the UE may generate pilots for ACK with length-2 orthogonal sequence q (m), as shown in equation (4), to obtain two pilot sequences p₀(n) and p₁(n) of (a). The UE may send two pilot sequences p in two symbol periods 2 and 3 of the left slot and also in two symbol periods 8 and 9 of the right slot₀(n) and p₁(n) as shown in FIG. 3B. The UE also processes the data for ACK with an orthogonal sequence w (m) of length 4, as shown in equations (7) and (8), to obtain four data sequences z₀(n) to z₃(n) of (a). The UE may be in four symbol periods 0,1, 4, and 5 of the left slot and alsoFour data sequences z are transmitted in the four symbol periods 6, 7, 10 and 11 of the right slot₀(n) to z₃(n) as shown in FIG. 3B.

For the design shown in fig. 3B, up to 12 UEs may use six reference signal sequences and two orthogonal sequences q₀(m) and q₁(m) simultaneously transmitting pilots for ACK. In one design, the 12 ACK channels may be defined with six reference signal sequences, two orthogonal sequences for pilot, and four orthogonal sequences for data. The number of ACK channels is limited to the number of UEs that can send pilots simultaneously. Each ACK channel is associated with a designated reference signal sequence r (n), a designated orthogonal sequence q (m) for pilot, and a designated orthogonal sequence w (m) for data. Up to 12 UEs may send their ACK information simultaneously on up to 12 ACK channels on the same resource block pair.

In another design of an ACK structure for a slot with six symbol periods, pilot may be sent in three symbol periods of a resource block and data may be sent in the remaining three symbol periods of the resource block. In this design, length-3 orthogonal sequences may be used for pilot and data, and may be defined in the manner shown in equation set (3). In this design, 18 ACK channels may be defined with six reference signal sequences, three orthogonal sequences for pilot, and three orthogonal sequences for data. Up to 18 UEs may send their ACK information simultaneously on up to 18 ACK channels on the same resource block pair.

A number of exemplary designs of ACK structures have been described above. In general, pilots may be transmitted in any number of symbol periods (M), and data may be transmitted in any number of symbol periods (L). A set of orthogonal sequences of length M may be used for pilot and a set of orthogonal sequences of length L may be used for data. Orthogonal sequences for pilot and data can be defined in terms of DFT, walsh, and/or other matrices of appropriate dimensions. The UE may broaden its pilot with the orthogonal sequence q (m) assigned to it for pilot and its data with the orthogonal sequence w (m) assigned to it for data.

Fig. 4 shows a design of a CQI structure 400 for the case where each slot includes seven symbol periods. In this design, a resource block for CQI includes five symbol periods for data and two symbol periods for pilot. In the design shown in fig. 4, for the left slot, pilot is transmitted in two symbol periods 2 and 4 separated by one symbol period, and data is transmitted in the remaining five symbol periods 0,1, 3, 5, and 6. The data and pilot for the CQI may also be sent in other symbol periods in the resource block. In order to capture the time variations in the wireless channel, it is desirable to separate the two symbol periods by at least one symbol period (e.g., by one, two, or three symbol periods).

In one design, the reference signal sequence may be used directly as a pilot sequence for the CQI. The UE may send its reference signal sequence in each symbol period for pilot without spreading. If six reference signal sequences are available, a maximum of six UEs may transmit pilots simultaneously with the six reference signal sequences. Each UE transmits its pilot with a designated reference signal sequence. Pilots from UEs may be distinguished by the differentiation of reference signal sequences in the frequency domain.

In one design, the UE may process the data for the CQI as follows. The UE first decodes the information bits of the CQI to obtain coded bits and maps the coded bits to ten modulation symbols d (0) to d (9). The UE then modulates its reference signal sequence r (n) with each modulation symbol d (m), as follows:

c_m(N) ═ d (m) · r (N) where N ═ 0., N-1 and m ═ 0., 9 formula (11)

Wherein, c_m(n) is a data sequence of CQI for symbol period m. Ten data sequences c may be acquired for ten modulation symbols d (0) to d (9), respectively₀(n) to c₉(n) and for ten symbol periods of data in one resource block pairTo transmit these data sequences.

In one design, six CQI channels may be defined with six reference signal sequences. Each CQI channel is associated with a designated reference signal sequence r (n). Up to six UEs may simultaneously send data and pilot for CQI on up to six CQI channels on the same resource block pair. The data and pilot from these UEs can be distinguished by the distinction of the reference signal sequences in the frequency domain.

In the CQI structure for a slot having six symbol periods, a resource block for CQI includes four symbol periods for data and two symbol periods for pilot. For example, pilot may be sent in two symbol periods 1 and 4, and data may be sent in the remaining four symbol periods 0, 2, 3, and 5. In another design, a resource block for CQI may include five symbol periods for data and one symbol period for pilot. For example, pilot may be sent in one symbol period 2 or 3 and data may be sent in the remaining five symbol periods. Data and pilot for CQI may also be sent in other symbol periods in the resource block with six symbol periods per slot.

Fig. 3A and 3B illustrate two exemplary designs of data and pilot for sending ACKs. Fig. 4 shows an exemplary design of data and pilot for transmitting CQI. The data and pilot for the ACK and CQI may also be sent in other manners, e.g., in different numbers of symbol periods, in different symbol periods of a resource block, and so on.

The ACK and CQI channels may also be multiplexed on the same resource block. Modulating the entire reference signal sequence with a modulation symbol (e.g., a modulation symbol for ACK or CQI information) or a symbol of an orthogonal sequence (e.g., an orthogonal sequence for pilot) does not change the correlation property of the reference signal sequence. For the designs shown in fig. 3A and 4 and using six reference signal sequences, a single resource block pair may support one of the following configurations: 18 ACK channels, 1 CQI channel and 15 ACK channels, 2 CQI channels and 12 ACK channels, 3 CQI channels and 9 ACK channels, 4 CQI channels and 6 ACK channels, 5 CQI channels and 3 ACK channels, or 6 CQI channels.

Fig. 5 shows a block diagram of a design of node 110 and UE120, which are one of the node bs and one of the UEs in fig. 1. In this design, UE120 is equipped with T antennas 532a through 532T and node B110 is equipped with R antennas 552a through 552R, where, in general, T ≧ 1 and R ≧ 1.

At UE120, a transmit processor 520 receives traffic data from a data source 512, processes (e.g., encodes and symbol maps) the traffic data, and provides data symbols. Transmit processor 520 also receives control information (e.g., ACK and/or CQI information) from a controller/processor 540, processes the control information as described above, and provides control symbols (e.g., for a data sequence). Transmit processor 520 also generates pilot symbols (e.g., for pilot sequences) and multiplexes the pilot symbols with the data symbols and control symbols. Data symbols are symbols for traffic data, control symbols are symbols for control information, pilot symbols are symbols for pilot, and symbols may be real or complex valued. The pilot symbols may also be referred to as reference symbols.

A MIMO processor 522 processes (e.g., precodes) the symbols from transmit processor 520 and provides T output symbol streams to T Modulators (MODs) 530a through 530T. MIMO processor 522 may be omitted if UE120 is equipped with a single antenna. Each modulator 530 processes its output symbol stream (e.g., for single-carrier frequency division multiplexing (SC-FDM)) to obtain an output sample stream. Each modulator 530 also conditions (e.g., converts to analog, filters, amplifies, and frequency upconverts) its output sample stream to generate an uplink signal. T uplink signals from modulators 530a through 530T may be transmitted through T antennas 532a through 532T, respectively.

At node B110, antennas 552a through 552r receive uplink signals from UE120 and/or other UEs. Each antenna 552 provides a received signal to a respective demodulator (DEMOD) 554. Each demodulator 554 conditions (e.g., filters, amplifies, downconverts, and digitizes) its received signal to obtain samples and further processes the samples (e.g., for SC-FDM) to obtain received symbols. A MIMO detector 556 detects on the received symbols from all R demodulators 554a through 554R and provides detected symbols. A receive processor 560 processes (e.g., demodulates and decodes) the detected symbols and provides decoded traffic data to a data sink 562 and decoded control information to a controller/processor 570. In general, the processing by MIMO detector 556 and receive processor 560 is complementary to the processing by MIMO processor 522 and transmit processor 520, respectively, at UE 120.

Node B110 may send traffic data and/or control information to UE120 on the downlink. Traffic data from a data source 578 and/or control information from controller/processor 570 is processed by a transmit processor 580 and further processed by a MIMO processor 582 to obtain R output symbol streams. R modulators 554a through 554R process the R output symbol streams (e.g., for OFDM) to obtain R output sample streams and further condition the output sample streams to obtain R downlink signals, which may be transmitted via R antennas 552a through 552R. At UE120, the downlink signals from node B110 may be received by antennas 532a through 532t, conditioned and processed by demodulators 530a through 530t, and further processed by a MIMO detector 536 (if applicable) and a receive processor 538 to recover the traffic data and control information sent to UE 120. Receive processor 538 provides the traffic data to a data sink 539 and the control information to controller/processor 540.

Controllers/processors 540 and 570 direct the operation at UE120 and node B110, respectively. Memories 542 and 572 store data and program codes for UE120 and node B110, respectively. A scheduler 574 schedules UEs for data transmission on the downlink and/or uplink and allocates resources for the scheduled UEs. Scheduler 574 also allocates ACK and CQI resources for the UEs for transmission of ACK and CQI information. The ACK and CQI resources include resource blocks, reference signal sequences, orthogonal sequences for pilot, orthogonal sequences for data, and so on.

Fig. 6 shows a block diagram of a design of transmit processor 620 for ACK, which may be part of transmit processor 520 at UE120 in fig. 5. In transmit processor 620, a symbol mapper 622 maps the ACK information to modulation symbol d (0). Multiplier 624 multiplies the reference signal sequence r (n) with the modulation symbols and provides a modulation sequence y (n), e.g., as shown in equation (7). Data spreader 626 spreads the modulated sequence with an orthogonal sequence w (m) for data and provides a data sequence z_m(n), for example, as shown in equation (8). The pilot spreader 628 spreads the reference signal sequence with an orthogonal sequence q (m) for pilot and provides a pilot sequence p_m(n), for example, as shown in equation (4). A multiplexer (Mux) 630 receives the data sequence from spreader 626 and the pilot sequence from spreader 628 and provides each sequence in a suitable symbol period, e.g., as shown in fig. 3A or 3B.

Fig. 7 shows a block diagram of a design of a transmit processor 720 for CQI, which may be part of transmit processor 520 at UE120 in fig. 5. In transmit processor 720, an encoder 722 encodes only the CQI information or both the CQI and ACK information to obtain coded bits. A symbol mapper 724 maps the coded bits to modulation symbols d (m). A multiplier 726 multiplies the reference signal sequence r (n) with each modulation symbol and provides a corresponding data sequence c_m(n), for example, as shown in formula (11). Multiplexer 728 receives the data sequences from multiplier 726 and the reference signal sequence, provides each data sequence in a respective symbol period for data, and provides the reference signal sequence as a pilot sequence in each symbol period for pilot, e.g., as shown in fig. 4.

FIG. 8 shows a design of an SC-FDM modulator 830, which may be used for each of modulators 530a through 530t at UE120 in FIG. 5 when sending ACK or CQI. In SC-FDM modulator 830, DFT unit 832 receives a data or pilot sequence comprising N symbols for a symbol period, performs an N-point DFT on the N symbols, and provides N frequency-domain values. A symbol-to-subcarrier mapper 834 maps N frequency-domain values to N subcarriers in a resource block for ACK or CQI and zero values to the remaining subcarriers. An Inverse Fast Fourier Transform (IFFT) unit 836 performs a K-point IFFT on the K mapped values for the K total subcarriers and provides K time-domain samples for the useful portion. Cyclic prefix generator 838 copies the last C samples of the useful portion and appends these C samples to the front of the useful portion to form an SC-FDM symbol containing K + C samples. An SC-FDM symbol may be transmitted in one symbol period that includes K + C sample periods.

FIG. 9 shows a block diagram of a design of an SC-FDM demodulator 950, which may be used for each of the demodulators 554a through 554r at node B110 in FIG. 5 when receiving ACK or CQI. In SC-FDM demodulator 950, a cyclic prefix removal unit 952 obtains K + C received samples in each symbol period, removes the C received samples corresponding to the cyclic prefix, and provides K received samples for the useful portion. A Fast Fourier Transform (FFT) unit 954 performs a K-point FFT on the K received samples and provides K frequency-domain values for the K total subcarriers. Symbol-to-subcarrier demapper 956 provides the N frequency-domain values from the N subcarriers in the resource block allocated to UE120 and discards the remaining frequency-domain values. IDFT unit 958 performs an N-point IDFT on the N frequency-domain values and provides N received symbols for the received data or pilot sequence.

Fig. 10 shows a block diagram of a design of a receive processor 1060 for an ACK, which may be part of receive processor 560 at node B110 in fig. 5. Within receive processor 1060, a demultiplexer (Demux) 1062 obtains the data and pilot sequences for the received ACK from the resource block pair assigned to UE120, provides the received pilot sequences to a pilot despreader 1064, and provides the received data sequences to a correlation detector 1070. Pilot despreader 1064 despreads the received pilot sequence for each resource block with an orthogonal sequence q (m) assigned to UE120 and provides a despread pilot sequence for the resource block. In one design, pilot despreading for each resource block may be performed as follows:

formula (12)

Wherein the content of the first and second substances,is the received pilot sequence for symbol period m;

is the despread pilot sequence.

Channel estimator 1066 may derive channel estimates for the N subcarriers in each resource block from the despread pilot sequences for that resource block. A correlation detector 1070 performs correlation detection on each received data sequence with the applicable channel estimate and provides a corresponding detected data sequence. Data despreader 1072 despreads the detected data sequence for each resource block with the orthogonal sequence w (m) assigned to UE120 to obtain a despread data sequence for that resource block. In one design, data despreading for each resource block may be performed as follows:

formula (13)

Wherein, b_m(n) is the detected data sequence for symbol period m;

is the despread data sequence, which is an estimate of y (n) in equation (7).

Correlator 1074 correlates the despread data sequence for each resource block with each possible reference signal sequence and provides a correlation calculation result for the optimal reference signal sequence. The symbol decoder 1076 may obtain a correlation calculation of the two resource blocks for ACK, determine from the correlation calculation the modulation symbols most likely to have been transmitted by the UE120, and provide the received ACK information to the UE.

Fig. 11 shows a block diagram of a design of a receive processor 1160 for CQI, which is part of receive processor 560 at node B110 in fig. 5. Within receive processor 1160, a demultiplexer 1162 may obtain data and pilot sequences for the received CQI from the resource block pairs assigned to UE120, provide each received pilot sequence to a channel estimator 1164, and provide the received data sequences to a correlation detector 1170. Channel estimator 1164 obtains one or more channel estimates for the N subcarriers in each resource block based on the pilot sequence received for that resource block. In one design, channel estimator 1164 may obtain channel estimates for each resource block based on all received pilot sequences for that resource block. This design may be used for slowly varying channels, e.g., lower mobility situations. In another design, channel estimator 1164 may obtain a channel estimate for each symbol period in each resource block based on the received pilot sequence for that resource block (e.g., via interpolation). This design may be used for fast changing channels, e.g. in case of higher mobility.

A correlation detector 1170 performs correlation detection on each received data sequence with the applicable channel estimate and provides a corresponding detected data sequence. Correlator 1172 correlates each detected data sequence with each possible reference signal sequence and provides a correlation value for the optimal reference signal sequence. A unit 1174 calculates log-likelihood ratios (LLRs) from the correlation values of the detected data sequences. A decoder 1176 decodes the LLRs for all data sequences and provides received CQI information for UE 120.

Fig. 10 and 11 illustrate processes performed by node B110 to recover the ACK and CQI information sent by UE 120. Node B110 may also perform processing for ACKs and CQIs in other manners. For example, each of correlator 1074 in fig. 10 and correlator 1172 in fig. 11 may be replaced with a detector capable of detecting a reference signal sequence assigned to UE 120. These processes may also be performed in a different order than that shown in fig. 10 and 11. The node B110 may perform a process in a time domain (e.g., as shown in fig. 10 and 11) on receiving the data and pilot sequences provided by the IDFT unit 958 in fig. 9 in the time domain. Alternatively, the node B110 may perform a process in the frequency domain on the data and pilot sequences received in the frequency domain, which are provided by the demapper 956 in fig. 9.

Node B110 may receive data and pilot sequences from UE120 through multiple antennas 552a through 552 r. In this case, node B110 combines the results from the multiple antennas, e.g., after correlation detector 1070 in fig. 10 or despreader 1072, after correlation detector 1170 in fig. 11. Node B110 may also combine between multiple antennas at other stages in the processing for ACK and CQI.

Fig. 12 shows a design of a process 1200 for sending ACK data and pilot. Process 1200 may be performed by a UE or some other entity. The UE may be assigned a reference signal sequence selected from a set of reference signal sequences generated from different cyclic shifts of a base sequence. The UE may also be assigned an orthogonal sequence selected from a set of orthogonal sequences generated from a DFT matrix or a walsh matrix. The UE may spread the reference signal sequence with orthogonal sequences to obtain multiple pilot sequences (block 1212). The UE may then transmit the multiple pilot sequences on multiple (e.g., 12) subcarriers in multiple symbol periods, one pilot sequence in each symbol period, each pilot sequence being transmitted on the multiple subcarriers (block 1214). The plurality of symbol periods may be consecutive symbol periods in a resource block.

In one design, the UE may widen the reference signal sequence with an orthogonal sequence of length three to obtain three pilot sequences. The UE then transmits the three pilot sequences in the middle three symbol periods of a slot that includes seven symbol periods (e.g., as shown in fig. 3A). In another design, the UE may widen the reference signal sequence with an orthogonal sequence of length two to obtain two pilot sequences. The UE then transmits the two pilot sequences in the middle two symbol periods of a slot that includes six symbol periods (e.g., as shown in fig. 3B).

The UE may be assigned a second orthogonal sequence selected from a set of orthogonal sequences generated from a DFT matrix or a walsh matrix. The UE may modulate the reference signal sequence with the ACK information to obtain a modulated sequence (block 1216). The UE may then broaden the modulation sequence with a second orthogonal sequence to obtain multiple data sequences (block 1218). The UE may transmit the plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data, each data sequence being transmitted on the plurality of subcarriers (block 1220). In one design, the UE may widen the modulation sequence with an orthogonal sequence of length four to obtain four data sequences. The UE may then transmit the four data sequences in the four symbol periods of one slot, e.g., as shown in fig. 3A or 3B.

In one design, the UE may generate multiple SC-FDM symbols from multiple pilot sequences, where each pilot sequence is for one SC-FDM symbol. The UE may also generate multiple SC-FDM symbols from multiple data sequences, where each data sequence is for one SC-FDM symbol. The UE may send each SC-FDM symbol in a different symbol period.

Fig. 13 shows a design of an apparatus 1300 for sending data and pilot for ACK. The apparatus 1300 includes: a module 1312 for spreading a reference signal sequence with orthogonal sequences to obtain a plurality of pilot sequences; a module 1314 for transmitting a plurality of pilot sequences on a plurality of subcarriers in a plurality of symbol periods, one pilot sequence in each symbol period; a module 1316 for modulating the reference signal sequence with the ACK information to obtain a modulated sequence; a module 1318 for spreading the modulation sequence with a second orthogonal sequence to obtain a plurality of data sequences; a module 1320 for transmitting the plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data.

Fig. 14 shows a design of a process 1400 for sending data and pilot for CQI. Process 1400 may be performed by the UE or some other entity. The UE may be assigned a reference signal sequence selected from a set of reference signal sequences generated from different cyclic shifts of a base sequence. The UE may generate a plurality of pilot sequences based on the reference signal sequence (block 1412). In one design, the UE sets each pilot sequence equal to a reference signal sequence. The UE may also generate pilot sequences in other manners based on the reference signal sequence. The UE may transmit the plurality of pilot sequences on a plurality of subcarriers in a plurality of symbol periods separated by at least one symbol period, one pilot sequence in each symbol period, each pilot sequence being transmitted on the plurality of subcarriers (block 1414).

The UE may generate a plurality of modulation symbols based on the CQI information or the CQI and ACK information (block 1416). The UE may modulate a reference signal sequence with a plurality of modulation symbols to obtain a plurality of data sequences (block 1418). The UE may transmit the plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data, each data sequence being transmitted on the plurality of subcarriers (block 1420).

In one design, the UE may generate two pilot sequences from a reference signal sequence and transmit the two pilot sequences in two symbol periods in each of two slots. Each slot includes seven symbol periods, and the two symbol periods for pilot may be separated by at least one symbol period. The UE generates ten data sequences from the reference signal sequence and ten modulation symbols and transmits the ten data sequences in the remaining ten symbol periods in two slots. The UE may also generate and transmit different numbers of pilot sequences and data sequences.

Fig. 15 shows a design of an apparatus 1500 for transmitting data and pilot for CQI. The apparatus 1500 includes: a module 1512 for generating a plurality of pilot sequences from a reference signal sequence; a module 1514 for transmitting a plurality of pilot sequences on a plurality of subcarriers in a plurality of symbol periods separated by at least one symbol period, one pilot sequence in each symbol period; a module 1516 for generating a plurality of modulation symbols based on the CQI information or the CQI and ACK information; a module 1518 for modulating the reference signal sequence with the plurality of modulation symbols to obtain a plurality of data sequences; a module 1520 that operates to transmit the plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data.

FIG. 16 shows a design of a process 1600 for receiving an ACK. Process 1600 may be performed by a node B or some other entity. The node B may receive multiple (e.g., two or three) pilot sequences from the UE on multiple subcarriers in multiple symbol periods, one pilot sequence in each symbol period (block 1612). The node B may despread the multiple pilot sequences with orthogonal sequences (e.g., of length 2 or 3) to obtain despread pilot sequences (block 1614). The node B may derive a channel estimate from the despread pilot sequence (block 1616). The node B may perform despreading and channel estimation in the time domain as well as in the frequency domain.

The node B also receives a plurality of (e.g., four) data sequences on a plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data (block 1618). The node B may perform correlation detection on the multiple data sequences using the channel estimates to obtain multiple detected data sequences (block 1620). The node B may despread the plurality of detected data sequences with a second orthogonal sequence (e.g., of length 4) to obtain despread data sequences (block 1622). The node B may then recover the ACK information from the UE based on the despread data sequence (block 1624).

Fig. 17 shows a design of an apparatus 1700 for receiving an ACK. The apparatus 1700 includes: a module 1712 for receiving a plurality of pilot sequences from the UE on a plurality of subcarriers in a plurality of symbol periods, one pilot sequence in each symbol period; a module 1714 configured to despread the plurality of pilot sequences with the orthogonal sequence to obtain despread pilot sequences; a module 1716 for deriving a channel estimate from the despread pilot sequence; a module 1718 for receiving a plurality of data sequences on a plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data; a module 1720 for performing correlation detection on the plurality of data sequences with channel estimates to obtain a plurality of detected data sequences; a module 1722, configured to despread the plurality of detected data sequences with the second orthogonal sequence to obtain despread data sequences; a block 1724 may be utilized to recover the ACK information from the UE based on the despread data sequence.

Fig. 18 shows a design of a process 1800 for receiving CQI. Process 1800 may be performed by a node B or some other entity. The node B may receive multiple (e.g., two) pilot sequences from the UE on multiple subcarriers in multiple symbol periods separated by at least one symbol period, one pilot sequence in each symbol period (block 1812). The node B may derive a channel estimate based on the plurality of pilot sequences (block 1814). The node B may also receive a plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data (block 1816). The node B may perform correlation detection on the plurality of data sequences with the channel estimate to obtain a plurality of detected data sequences (block 1818). The node B may then recover CQI information or CQI and ACK information from the UE based on the plurality of detected data sequences (block 1820).

Fig. 19 shows a design of an apparatus 1900 for receiving CQI. The apparatus 1900 includes: a module 1912 for receiving a plurality of pilot sequences from the UE on a plurality of subcarriers in a plurality of symbol periods separated by at least one symbol period, one pilot sequence in each symbol period; a module 1914 for deriving a channel estimate from the plurality of pilot sequences; a module 1916 for receiving a plurality of data sequences on the plurality of subcarriers in a plurality of symbol periods for data, one data sequence in each symbol period for data; a module 1918 for performing correlation detection on the plurality of data sequences with channel estimates to obtain a plurality of detected data sequences; a module 1920 configured to recover CQI information or CQI and ACK information from the UE based on the plurality of detected data sequences.

Fig. 20 shows a design of a process 2000 for supporting ACK and CQI transmission by a UE. Process 2000 may be performed by a node B or some other network entity. The node B may select a first and second orthogonal sequence from a set of orthogonal sequences generated from a DFT matrix (block 2012). The node B may select first and second reference signal sequences from a set of reference signal sequences generated from different cyclic shifts of a base sequence (block 2014). The node B may assign a first reference signal sequence and a first orthogonal sequence to a first UE for transmitting pilot (block 2016). The node B may assign a second reference signal sequence and a second orthogonal sequence to a second UE for transmitting pilot (block 2018). The node B may then receive a first set of pilot sequences from the first UE on a plurality of subcarriers in a plurality of symbol periods (block 2020). The first set of pilot sequences is generated by a first UE based on a first reference signal sequence and a first orthogonal sequence. The node B may also receive a second set of pilot sequences from a second UE on the plurality of subcarriers in the plurality of symbol periods (block 2022). The second set of pilot sequences is generated by the second UE based on the second reference signal sequence and the second orthogonal sequence.

The node B may also allocate the first reference signal sequence and the second orthogonal sequence to a third UE for transmitting pilot. The node B may also allocate a second reference signal sequence and the first orthogonal sequence to a fourth UE for transmitting pilot. In general, each UE may be assigned a different combination of reference signal sequences and orthogonal sequences for transmitting pilots on the same resource block.

The node B may select the third and fourth orthogonal sequences from a set of orthogonal sequences generated based on the walsh matrix. The node B may assign a third orthogonal sequence to the first UE for transmitting data and a fourth orthogonal sequence to the second UE for transmitting data. Thereafter, the node B may receive a first set of data sequences from the first UE on a plurality of subcarriers in a plurality of symbol periods for data. The first set of data sequences is generated by the first UE based on the first reference signal sequence and the third orthogonal sequence. The node B receives a second set of data sequences from a second UE on the plurality of subcarriers in the plurality of symbol periods for data. The second set of data sequences is generated by the second UE based on the second reference signal sequence and the fourth orthogonal sequence.

Fig. 21 shows a design of an apparatus 2100 for supporting ACK and CQI transmission by a UE. The apparatus 2100 comprises: a module 2112 for selecting a first and a second orthogonal sequence from a set of orthogonal sequences generated from the DFT matrix; a module 2114 for selecting a first and a second reference signal sequence from a set of reference signal sequences generated from different cyclic shifts of a base sequence; a module 2116 for allocating a first reference signal sequence and a first orthogonal sequence to a first UE for transmitting pilot; a module 2118 for assigning a second reference signal sequence and a second orthogonal sequence to a second UE for transmitting pilot; a module 2120 for receiving a first set of pilot sequences from a first UE on a plurality of subcarriers in a plurality of symbol periods; a module 2122 configured to receive a second set of pilot sequences from a second UE on the plurality of subcarriers in the plurality of symbol periods.

The modules in fig. 13, 15, 17, 19, and 21 may comprise processors, electronics devices, hardware devices, electronics components, logic circuits, memories, etc., or any combination thereof.

Those of skill in the art would also understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more example designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a computer. Further, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source over a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description of the invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the present invention is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A method for wireless communication, comprising the steps of:

selecting a first and a second orthogonal sequence from a set of orthogonal sequences generated from a Discrete Fourier Transform (DFT) matrix;

selecting first and second reference signal sequences from a set of reference signal sequences generated based on different cyclic shifts of a base sequence;

allocating the first reference signal sequence and the first orthogonal sequence to a first User Equipment (UE) for transmitting a pilot;

allocating the second reference signal sequence and the second orthogonal sequence to a second UE for transmitting pilot.

2. The method of claim 1, further comprising the steps of:

receiving a first set of pilot sequences from the first UE on a plurality of subcarriers in a plurality of symbol periods, the first set of pilot sequences generated by the first UE from the first reference signal sequence and the first orthogonal sequence;

receiving a second set of pilot sequences from the second UE on the plurality of subcarriers in the plurality of symbol periods, the second set of pilot sequences generated by the second UE based on the second reference signal sequence and the second orthogonal sequence.

3. The method of claim 1, further comprising the steps of:

allocating the first reference signal sequence and the second orthogonal sequence to a third UE for transmitting pilot;

allocating the second reference signal sequence and the first orthogonal sequence to a fourth UE for transmitting pilot.

4. The method of claim 1, further comprising the steps of:

selecting third and fourth orthogonal sequences from a second set of orthogonal sequences generated from a walsh matrix;

allocating the third orthogonal sequence to the first UE for transmitting data;

allocating the fourth orthogonal sequence to the second UE for transmitting data.

5. The method of claim 4, further comprising the steps of:

receiving a first set of data sequences from the first UE on a plurality of subcarriers in a plurality of symbol periods, the first set of data sequences generated by the first UE from the first reference signal sequence and the third orthogonal sequence;

receiving a second set of data sequences from the second UE on the plurality of subcarriers in the plurality of symbol periods, the second set of data sequences generated by the second UE from the second reference signal sequence and the fourth orthogonal sequence.

6. An apparatus for wireless communication, comprising:

means for selecting a first and a second orthogonal sequence from a set of orthogonal sequences generated from a Discrete Fourier Transform (DFT) matrix;

means for selecting a first and a second reference signal sequence from a set of reference signal sequences generated from different cyclic shifts of a base sequence;

means for allocating the first reference signal sequence and the first orthogonal sequence to a first User Equipment (UE) for transmitting pilot;

means for assigning the second reference signal sequence and the second orthogonal sequence to a second UE for transmitting pilot.

7. The apparatus of claim 6, further comprising:

means for receiving a first set of pilot sequences from the first UE on a plurality of subcarriers in a plurality of symbol periods, the first set of pilot sequences generated by the first UE from the first reference signal sequence and the first orthogonal sequence;

means for receiving a second set of pilot sequences from the second UE on the plurality of subcarriers in the plurality of symbol periods, the second set of pilot sequences generated by the second UE from the second reference signal sequence and the second orthogonal sequence.

8. The apparatus of claim 6, further comprising:

means for assigning the first reference signal sequence and the second orthogonal sequence to a third UE for transmitting pilot;

means for allocating the second reference signal sequence and the first orthogonal sequence to a fourth UE for transmitting pilot.

9. The apparatus of claim 6, further comprising:

means for selecting a third and a fourth orthogonal sequence from a second set of orthogonal sequences generated from a walsh matrix;

means for assigning the third orthogonal sequence to the first UE for transmitting data;

means for assigning the fourth orthogonal sequence to the second UE for transmitting data.

10. The apparatus of claim 9, further comprising:

means for receiving a first set of data sequences from the first UE on a plurality of subcarriers in a plurality of symbol periods, the first set of data sequences generated by the first UE from the first reference signal sequence and the third orthogonal sequence;

means for receiving a second set of data sequences from the second UE on the plurality of subcarriers in the plurality of symbol periods, the second set of data sequences generated by the second UE from the second reference signal sequence and the fourth orthogonal sequence.