HK1193260B - Variable control channel for a wireless communication system - Google Patents

Description

Variable control channel for wireless communication system

The present application is a divisional application of an application having an application date of 24/07/2007, an application number of 200780034642.1, and a name of "variable control channel of wireless communication system".

This application claims priority to the following applications: US application entitled "METHOD AND APPARATUS FOR VARIABLE CONTROL DOWNLINKALLOCATION" filed 24.7.2006, AND US application entitled "A METHOD AND APPARATUS FOR VARIABLE CONTROL OF ASYMMETRIC STRUCTURE FOR ASYMMETRIC DOWNLINKALLATIONS" filed 24.7.2006, both of which are assigned to the assignee of the present application AND are hereby expressly incorporated herein by reference.

Technical Field

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

Background

Wireless communication systems are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and so on. These wireless systems may be 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 (or base station) may transmit data to a User Equipment (UE) on a downlink and/or receive data from the UE on an uplink. The downlink (or forward link) refers to the communication link from the node bs to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the node bs. The node B also sends control information (e.g., allocation of system resources) to the UE. Similarly, the UE may send control information to the node B to support data transmission on the downlink and/or for other purposes. It is desirable to transmit data and control information as efficiently as possible to improve system performance.

Disclosure of Invention

Techniques for transmitting control information on a variable control channel are described. The variable control channel may support transmission of one or more types of control information with a variable amount of resources. Different structures for mapping the control information to the resources are used according to different factors, such as an operation configuration, variable resources of a control channel, a type of control information to be transmitted, an amount of each type of control information to be transmitted, whether data is transmitted, and the like. Accordingly, the structure of the control channel may vary depending on these factors.

In one design, at least one type of control information may be determined to be transmitted, and the at least one type of control information may include only Channel Quality Indicator (CQI) information, only Acknowledgement (ACK) information, both CQI and ACK information, and/or other types of control information. The structure of the control channel is determined based on the operating configuration and/or other factors. The operational configuration is determined based on the system configuration, UE configuration, etc. The system configuration represents the number of subframes allocated for the downlink and the number of subframes allocated for the uplink. The UE configuration indicates downlink subframes and uplink subframes available to the UE in the allocated subframes. The control channel structure is determined based on asymmetry of downlink and uplink allocations. In one design, a control channel includes: (i) a fixed amount of resources from the control segment when no data is being transmitted, and (ii) a variable amount of resources from the data segment when data is being transmitted. Based on the structure, at least one type of control information is mapped to resources of the control channel. Based on this structure, each type of control information is mapped to a respective portion of the control channel resources.

Various aspects and features of the disclosure are described in detail below.

Drawings

Fig. 1 illustrates a wireless communication system.

Fig. 2 shows exemplary transmissions on the downlink and uplink.

Fig. 3 shows a structure for transmitting data and control information.

Fig. 4A illustrates transmission of only control information.

Fig. 4B illustrates transmission of data and control information.

Fig. 5 shows a time structure of a Time Division Duplex (TDD) mode.

Fig. 6 shows a transmission with asymmetric downlink and uplink allocations.

Fig. 7A and 7B illustrate control channel structures for transmitting CQI and/or ACK information on a control segment.

Fig. 7C and 7D illustrate control channel structures for transmitting CQI and/or ACK information on a data segment.

Fig. 8 shows a process for transmitting control information.

Fig. 9 shows an apparatus for transmitting control information.

Fig. 10 shows a process for receiving control information.

Fig. 11 shows an apparatus for receiving control information.

Fig. 12 shows a block diagram of a node B and a UE.

Fig. 13 shows a block diagram of a modulator of control information.

Fig. 14 shows a block diagram of a modulator of data and control information.

Fig. 15 shows a block diagram of a demodulator.

Detailed Description

Fig. 1 illustrates a wireless communication system 100 with multiple node bs 110 and multiple UEs 120. In general, a node B is a fixed station that communicates with UEs and may also be referred to as an evolved node B (enode B), a base station, an access point, etc. Each node B110 provides communication coverage for a particular geographic area and supports communication for UEs located in the coverage area. The term "cell" refers to a node B and/or its coverage area depending on the context in which the term is used. A system controller 130 may couple to and coordinate and control the node bs. System controller 130 may be a single network entity or a collection of network entities such as a Mobility Management Entity (MME)/System Architecture Evolution (SAE) gateway, a Radio Network Controller (RNC), etc.

UEs 120 may be dispersed throughout the system, and each UE may be fixed or mobile. A UE may also be called a mobile station, mobile device, terminal, access terminal, subscriber unit, station, etc. The UE may be a cellular telephone, a Personal Digital Assistant (PDA), a wireless communication device, a handheld device, a wireless modem, a laptop computer, or the like.

A node B may transmit data on the downlink to one or more UEs and/or receive data on the uplink from one or more UEs at any given moment. The node B may also transmit and/or receive control information to and/or from the UE. In fig. 1, solid lines with double arrows (e.g., between node B110 a and UE 120B) represent data transmission on the downlink and uplink, and transmission of control information on the uplink. The solid line with a single arrow pointing to a UE (e.g., UE120 e) represents data transmission on the downlink and transmission of control information on the uplink. The solid line with a single arrow from a UE (e.g., UE120 c) represents the transmission of data and control information on the uplink. The dashed line with a single arrow from a UE (e.g., UE120 a) represents transmission of control information (but no data) on the uplink. For simplicity, the transmission of control information on the downlink is not shown in fig. 1. A given UE may receive data on the downlink, transmit data on the uplink, and/or transmit control information on the uplink at any given moment.

Fig. 2 shows an example of downlink transmission of a node B and uplink transmission of a UE. The UE may periodically estimate the downlink channel quality of the node B and send CQI information to the node B. The node B may use the CQI information to select an appropriate rate (e.g., a coding rate and a modulation scheme) for Downlink (DL) data transmission to the UE. When there is data to send and system resources are available, the node B may process the data and send the data to the UE. The UE may process a downlink data transmission from the node B, send an Acknowledgement (ACK) if the data is decoded correctly, and send a Negative Acknowledgement (NAK) if the data is decoded in error. If a NAK is received, the node B retransmits the data, and if an ACK is received, new data may be transmitted. The UE may also transmit data to the node B on the Uplink (UL) when there is data to transmit and uplink resources are allocated for the UE.

As shown in fig. 2, the UE may transmit data and/or control information at any given time interval, or none. Control information may also be referred to as control, overhead, signaling, and so on. The control information may include ACK/NAK, CQI, other information, or any combination thereof. The type and amount of control information depends on various factors, such as the number of data streams to be transmitted, whether to transmit using multiple-input multiple-output (MIMO), and the like. For simplicity, much of the description below assumes that the control information includes CQI and ACK information.

The system may support Hybrid Automatic Retransmission (HARQ), which may also be referred to as incremental redundancy, chase combining, and so on. For HARQ on the downlink, the node B may send a transmission of the packet and may send one or more retransmissions before the packet is decoded correctly by the UE, or before the maximum number of retransmissions has been sent, or some other termination condition is encountered. HARQ may improve the reliability of data transmission.

Z HARQ interlaces may be defined, where Z may be any integer value. Each HARQ interlace may include time intervals that are spaced apart from each other by a Z time interval. For example, 6 HARQ interlaces may be defined, and HARQ interlace z may include time intervals n + z, n + z +6, n + z +12, etc., where z ∈ {1, …,6 }.

The HARQ process may be referred to as total transmission and retransmission of the packet (if any). The HARQ process may start when resources are available and may terminate after the first transmission or after one or more subsequent retransmissions. The HARQ process may have a variable duration depending on the decoding result of the receiver. Each HARQ process may be transmitted on one HARQ interlace. In one design, up to Z HARQ processes may be transmitted on Z HARQ interlaces. In another design, multiple HARQ processes may be sent on different resources (e.g., on different subcarrier groups or from different antennas) for the same HARQ interlace.

The transmission techniques described herein may be used for uplink transmissions as well as downlink transmissions. The techniques may also be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA and SC-FDMA 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 Low Chip Rate (LCR). Cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA system may implement a radio technology such as global system for mobile communications (GSM). OFDMA systems may implement, for example, evolved UTRA (E-UTRA), IEEE802.11, IEEE 802.16, IEEE 802.20, flash-(Flash-) Etc. radio technologies. These radio technologies and standards are known in the art. UTRA, E-UTRA and GSM are part of the Universal Mobile Telecommunications System (UMTS). Long Term Evolution (LTE) is a future release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents of the organization entitled "third Generation partnership project" (3 GPP). Cdma2000 is described in a document entitled "third Generation partnership project 2" (3GPP2) organization. For clarity, certain aspects of the techniques for uplink transmission in LTE are described below, and 3GPP terminology is used in much of the description below.

LTE utilizes Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (N) orthogonal subcarriers, which are also commonly referred to as tones, frequency bins, etc. Each subcarrier may be modulated with data. Typically, modulation symbols are transmitted in the frequency domain using OFDM and in the time domain using SC-FDM. For LTE, the spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (N) depends on the system bandwidth. In one design, N is 512 for a system bandwidth of 5MHz, 1024 for a system bandwidth of 10MHz, and 2048 for a system bandwidth of 20 MHz. In general, N may be any integer value.

Fig. 3 shows a design of a structure 300 that may be used to transmit data and control information on the uplink. The transmission time axis is divided into a plurality of subframes. The subframes may have a fixed duration, e.g., 1 millisecond (ms), or a configurable duration. A subframe may be divided into 2 slots, each of which may include L symbol periods, where L may be any integer value, e.g., L ═ 6 or 7. Each symbol period may be used for data, control information, pilot, or any combination thereof.

In the design shown in fig. 3, a total of N subcarriers are divided into a data portion and a control portion. As shown in fig. 3, the control portion may be formed at the edge of the system bandwidth. The control portion has a configurable size that may be selected based on the amount of control information sent by the UE on the uplink. The data part includes all subcarriers not included in the control part. In the design of fig. 3, the data portion includes contiguous subcarriers, allowing a single UE to be allocated all of the contiguous subcarriers in the data portion.

A UE may be assigned a control segment with M contiguous subcarriers, where M may be a fixed or configurable value. The control segment may also be referred to as a Physical Uplink Control Channel (PUCCH). In one design, the control segment may include an integer multiple of 12 subcarriers. The UE may also be allocated a data segment with Q contiguous subcarriers, where Q may be a fixed or configurable value. The data segment may also be referred to as a Physical Uplink Shared Channel (PUSCH). In one design, the data segment may include an integer multiple of 12 subcarriers. In a given subframe, no data segment or control segment may be allocated to the UE.

It is desirable for the UE to transmit on contiguous subcarriers using SC-FDM, referred to as Local Frequency Division Multiplexing (LFDM). Transmitting on contiguous subcarriers results in a lower peak-to-average ratio (PAR). PAR is the ratio of the peak power of the waveform to the average power of the waveform. Low PAR is desirable because the Power Amplifier (PA) is allowed to operate at an average output power close to the peak output power. This may improve the throughput and/or link margin of the UE.

The UE may be assigned a control segment located near the edge of the system bandwidth. The UE may also be assigned a data segment within the data portion when there is data to send. The subcarriers of the control segment are not adjacent to the subcarriers of the data segment. The UE may send control information in the control segment if there is no data to send on the uplink. The UE may send data and control information in a data segment if there is data to send on the uplink. This dynamic transmission of control information may enable the UE to transmit control information on contiguous subcarriers regardless of whether there is data to send, and may improve PAR.

Fig. 4A illustrates transmission of control information in a subframe when there is no data to transmit on the uplink. A UE may be allocated a control segment that is mapped to different groups of subcarriers in two slots of a subframe. The UE may send control information on the subcarriers of the allocated control segment in each symbol period. The remaining subcarriers may be used for uplink transmission by other UEs.

Fig. 4B illustrates the transmission of data and control information when there is data to send on the uplink. A UE may be allocated a data segment that is mapped to different subcarrier groups in two slots of a subframe. The UE may send data and control information on the subcarriers of the allocated data segment in each symbol period. The remaining subcarriers may be used for uplink transmission by other UEs.

Fig. 4A and 4B illustrate frequency hopping between time slots. Frequency hopping may also be performed at other time intervals, e.g., from symbol period to symbol period, from subframe to subframe, etc. Frequency hopping can provide frequency diversity against adverse path effects and randomness of interference.

The system may support a Frequency Division Duplex (FDD) mode and/or a Time Division Duplex (TDD) mode. In FDD mode, separate frequency channels are available for the downlink and uplink, and downlink and uplink transmissions may be sent simultaneously on their separate frequency channels. In TDD mode, common frequency channels are available for downlink and uplink, and downlink transmissions may be sent during certain time periods and uplink transmissions during other time periods.

Fig. 5 illustrates a time structure 500 that may be used for TDD mode. Will be provided withThe transmission time axis is divided into a plurality of frame units. Each frame may span a predetermined duration, e.g., 10ms, and may be divided into a predetermined number of sub-frames. In each frame, N is allocated for the downlink_DLOne sub-frame, allocating N for uplink_ULAnd a sub-frame. N is a radical of_DLAnd N_ULMay be any suitable value and may also be configured based on the downlink and uplink traffic loads and/or other reasons.

The downlink and uplink may have symmetric or asymmetric allocations depending on the system configuration. For symmetric downlink and uplink allocations, the number of downlink subframes is equal to the number of uplink subframes, or N_DL＝N_ULFor example, a data transmission may be sent in a downlink subframe N, and control information for the data transmission may be sent in a corresponding uplink subframe N, where N ∈ {1, …, N_DL}. For asymmetric downlink and uplink allocations, the number of downlink subframes does not match the number of uplink subframes, or N_DL≠N_UL. Thus, there may be a mapping between uplink and downlink subframes that is not one-to-one. Asymmetric allocation may allow more flexible allocation of system resources to match load conditions, but may complicate system operation.

Fig. 6 illustrates an exemplary data transmission of asymmetric allocations of the downlink and uplink. In this example, M downlink subframes 1 to M may be associated with a single uplink subframe, where M may be any integer value. The UE may be allocated resources in downlink subframes 1 through M and associated uplink subframes. M packets for M HARQ processes may be transmitted to the UE in M downlink subframes. The UE may decode each packet and determine ACK information for the packet. The ACK information is also referred to as ACK feedback and may include an ACK or NAK. The UE may send ACK information for all M packets in an uplink frame. In fig. 6, ACK1 is ACK information sent for a packet for HARQ process H1, and ACKM is ACK information sent for a packet for HARQ process HM, where H1 through HM may be any available HARQ process. The ACK information may be used to control the transmission of new packets or the retransmission of erroneously decoded packets.

In an aspect, a variable control channel is used to support symmetric and asymmetric allocations of the downlink and uplink. For example, different amounts of resources are allocated to the control channel depending on whether data is transmitted or not. Different types of control information and/or different amounts of control information may be flexibly transmitted using the control channel.

For clarity, specific designs of the variable control channels are described below. In these designs, the control channel may be assigned 4 resource units in the control segment when data is not being transmitted, and the control channel may be assigned a variable number of resource units in the data segment when data is being transmitted. The resource unit may correspond to a physical resource or a logical resource. The physical resources may be resources for transmission and may be defined by subcarriers, symbol periods, and the like. Logical resources may be used to simplify resource allocation and may be mapped to physical resources based on mapping, translation, and the like. The resource unit may have any dimension and may be used to transmit one or more bits of control information. In the following design, the control channel may be used to send only CQI information for up to 3 HARQ processes, or only ACK information, or both CQI and ACK information, or no control information.

Fig. 7A shows a design of a control channel structure for transmitting ACK information for up to 3 HARQ processes on a control segment when CQI and data are not transmitted. In fig. 7A, 4 resource units of the control segment are represented by a2 × 2 matrix. The first and second rows of the matrix may correspond to 2 virtual frequency resources (VRFs) S1 and S2, respectively. The VFR may be a set of subcarriers, may be mapped to a set of subcarriers, or may correspond to some other logical or physical resource. The first and second columns of the matrix may correspond to two slots T1 and T2 of one subframe, respectively. The 4 blocks of the 2 x 2 matrix may correspond to 4 resource units of the control channel. In the following description, H1, H2, and H3 may be any 3 different HARQ processes.

In one design, the ACK information for 1 HARQ process H1 (ACK1) may be sent on all 4 resource elements of the control segment as shown in structure 712. For example, the ACK information may be repeated 4 times and sent on all 4 resource units to improve reliability.

In one design, the ACK information for 2 HARQ processes H1 and H2 may be sent on 4 resource elements of the control segment as shown in structure 714. In this design, ACK information for HARQ process H1 (ACK1) may be sent on 2 resource units occupying VFR S1 in slots T1 and T2. ACK information for HARQ process H2 (ACK2) may be sent on 2 resource units occupying VFR S2 in slots T1 and T2.

In one design, the ACK information for 3 HARQ processes H1, H2, and H3 may be sent on 4 resource elements of the control segment as shown in structure 716. In this design, ACK information for HARQ process H1 (ACK1) may be sent on 1 resource element occupying VFR S1 in slot T1. ACK information for HARQ process H2 (ACK2) may be sent on 1 resource element of VFR S2 in occupied slot T1. ACK information for HARQ process H3 (ACK3) may be sent on 1 resource element of VFR S1 in occupied slot T2. The remaining resource elements may be shared by 3 HARQ processes in a Time Division Multiplexing (TDM) manner. For example, this resource element may be used for ACK information for HARQ process H1 in one subframe, then for HARQ process H2 in the next subframe, then for HARQ process H3 in the next subframe, and so on. In another design, the ACK information for all 3 HARQ processes may be encoded by a (4, 3) block code and may be sent on all 4 resource elements. The ACK information for the 3 HARQ processes may also be sent in other manners.

Fig. 7B shows a design of a control channel structure for transmitting CQI and ACK information for up to 3 HARQ processes on a control segment when no data is transmitted. In one design, when no ACK information is sent, CQI information may be sent on all 4 resource units of the control segment as shown in structure 720.

In one design, the CQI and the ACK information for 1 HARQ process H1 may be sent on 4 resource elements of the control segment as shown in structure 722. In this design, CQI information may be sent on 2 resource elements occupying VFR S1 in slots T1 and T2. The ACK information for HARQ process H1 may be sent on 2 resource elements occupying VFR S2 in slots T1 and T2.

In one design, the CQI and the ACK information for 2 HARQ processes H1 and H2 may be sent on 4 resource units of the control segment as shown in structure 724. In this design, CQI information may be sent on 2 resource elements occupying VFR S1 in slots T1 and T2. The ACK information for HARQ process H1 may be sent on 1 resource element of VFR S2 in occupied slot T1. The ACK information for HARQ process H2 may be sent on 1 resource element of VFR S2 in occupied slot T2.

In one design, the CQI and the ACK information for 3 HARQ processes H1, H2, and H3 may be sent on 4 resource elements of the control segment as shown in structure 726. In this design, CQI information may be sent on 1 resource element occupying VFR S1 in time slot T1. The ACK information for HARQ process H1 may be sent on 1 resource element of VFR S2 in occupied slot T1. The ACK information for HARQ process H2 may be sent on 1 resource element of VFR S1 in occupied slot T2. The ACK information for HARQ process H3 may be sent on 1 resource element of VFR S2 in occupied slot T2.

Fig. 7C shows a design of a control channel structure for sending ACK information for up to 3 HARQ processes on a data segment when data is sent but CQI is not sent. The data segment may include 2K resource units and may be represented by a K × 2 matrix, where K may be any value. The K rows of the matrix correspond to K VFRs, S1 'through SK', where S1 'may be the lowest index of the K VFRs of the data segment and SK' may be the highest index of the K VFRs of the data segment. The first and second columns of the matrix correspond to 2 slots T1 and T2 of 1 subframe, respectively. The 2K blocks of the K × 2 matrix may correspond to 2K resource units. The resource units of the data segment may have the same or different size as the resource units of the control segment. As shown in fig. 7C, different numbers of resource units may be selected from the data segment and used to transmit different amounts of control information. The remaining resource units in the data segment are available for transmitting data.

In one design, the ACK information for 1 HARQ process H1 may be sent on 2 resource elements of the data segment as shown in structure 732. These 2 resource units may occupy VFR S1' in time slots T1 and T2. The remaining 2K-2 resource units are available for data.

In one design, the ACK information for 2 HARQ processes H1 and H2 may be sent on 4 resource elements of the data segment as shown in structure 734. In this design, the ACK information for HARQ process H1 may be sent on 2 resource elements occupying VFR S1' in slots T1 and T2. The ACK information for HARQ process H2 may be transmitted on 2 resource units occupying VFR S2' in slots T1 and T2. The remaining 2K-4 resource units are available for data.

In one design, the ACK information for 3 HARQ processes H1, H2, and H3 may be sent on 6 resource elements of the data segment as shown in structure 736. In this design, the ACK information for HARQ process H1 may be sent on 2 resource elements occupying VFR S1' in slots T1 and T2. The ACK information for HARQ process H2 may be transmitted on 2 resource units occupying VFR S2' in slots T1 and T2. The ACK information for HARQ process H3 may be transmitted on 2 resource elements of VFR S3' occupying the data segment in slots T1 and T2. The remaining 2K-6 resource units are available for data.

Fig. 7D shows a design of a control channel structure for transmitting CQI and ACK information for up to 3 HARQ processes on a data segment when data is transmitted. In one design, CQI information may be sent on 2 resource units of a data segment as shown in structure 740. These 2 resource units may occupy VFR S1' in time slots T1 and T2. The remaining 2K-2 resource units are available for data.

In one design, the CQI and the ACK information for 1 HARQ process H1 may be sent on 4 resource elements of the data segment as shown in structure 742. In this design, CQI information may be sent on 2 resource elements occupying VFR S1' in slots T1 and T2. The ACK information for HARQ process H1 may be transmitted on 2 resource units occupying VFR S2' in slots T1 and T2. The remaining 2K-4 resource units are available for data.

In one design, the CQI and the ACK information for 2 HARQ processes H1 and H2 may be sent on 6 resource elements of the data segment as shown in structure 744. In this design, CQI information may be sent on 2 resource elements occupying VFR S1' in slots T1 and T2. The ACK information for HARQ process H1 may be transmitted on 2 resource units occupying VFR S2' in slots T1 and T2. The ACK information for HARQ process H2 may be transmitted on 2 resource units occupying VFR S3' in slots T1 and T2. The remaining 2K-6 resource units are available for data.

In one design, the CQI and the ACK information for 3 HARQ processes H1, H2, and H3 may be sent on 8 resource elements of the data segment as shown in structure 746. In this design, CQI information may be sent on 2 resource elements occupying VFR S1' in slots T1 and T2. The ACK information for HARQ process H1 may be transmitted on 2 resource units occupying VFR S2' in slots T1 and T2. The ACK information for HARQ process H2 may be transmitted on 2 resource units occupying VFR S3' in slots T1 and T2. The ACK information for HARQ process H3 may be transmitted on 2 resource units occupying VFR S4' in slots T1 and T2. The remaining 2K-8 resource units are available for data.

Fig. 7A through 7D show specific designs of control channel structures for transmitting CQI and ACK information in a control segment and a data segment. These designs show a specific mapping of CQI and/or ACK information to resource units that may be used to send control information. The CQI and ACK information may also be mapped to available resource units in various other ways. For example, instead of using structure 714 in fig. 7A, the ACK information for HARQ process H1 may be sent on (i) the top-left and bottom-right resource elements in the matrix, (ii) the bottom-left and top-right resource elements in the matrix, (iii) the top-left and bottom-left resource elements in the matrix, and so on. As another example, a block code may be used for all control information being transmitted, and a composite codeword may be transmitted on all available resource units.

The CQI and ACK information may be multiplexed in various manners using, for example, Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), etc., or a combination thereof. In the designs shown in fig. 7A through 7D, a combination of TDM and FDM may be used for the control channels. In these designs, each VFR corresponds to a set of subcarriers. For example, 12 subcarriers are allocated for the control segment, each VFR corresponds to 6 subcarriers, and 1 resource element corresponds to 6 subcarriers in L symbol periods of one slot. For example, as shown in fig. 7A to 7D, CQI or ACK information for each HARQ process may be transmitted in the allocated resource units.

TDM may also be used for control information. In this case, all control information mapped to a given time slot is processed (e.g., joint coded) and transmitted on all subcarriers of the control channel in that time slot. For example, for structure 726 of fig. 7B, CQI and ACK information for HARQ process H1 may be processed and transmitted on all subcarriers in slot T1, and ACK information for HARQ processes H2 and H3 may be processed and transmitted on all subcarriers in slot T2.

FDM may also be used for control information. In this case, all control information mapped to a given VFR is processed (e.g., jointly coded) and transmitted on all subcarriers in the VFR of two slots. For example, for structure 726 of fig. 7B, CQI and ACK information for HARQ process H2 may be processed and transmitted on all subcarriers in VFR S1 for two slots T1 and T2, and ACK information for HARQ processes H1 and H3 may be processed and transmitted on all subcarriers in VFR S2 for two slots T1 and T2.

CDM may also be used for control information. In this case, the CQI and ACK information may be spread by an orthogonal code, combined, and then mapped to all resources available for transmitting control information.

The control information may also be transmitted by changing the modulation order. For example, BPSK may be used to transmit one bit of control information, QPSK may be used to transmit 2 information bits, 8-PSK may be used to transmit 3 information bits, 16-QAM may be used to transmit 4 information bits, and so on.

The design of fig. 7A through 7D assumes that two types of control information, CQI and ACK information, are transmitted. In general, any number and type of control information may be transmitted on a control channel. For example, the control information may include information identifying one or more desired subbands among all subbands, one or more precoding/beamforming matrices or information for one or more antennas for MIMO transmission, resource requests, and so on. Generally, a fixed amount or variable amount of control information is transmitted for each type. The amount of ACK information depends on the number of HARQ processes that are acknowledged. The amount of CQI information may be fixed (as shown in fig. 7A to 7D), or variable (e.g., depending on whether MIMO is used, the number of streams transmitted using MIMO, etc.).

The designs in fig. 7A through 7D assume that the control channel includes: (i) a fixed number of resource units when no data is transmitted, and (ii) a variable number of resource units when data is transmitted. In general, the control channels include: (i) a fixed or variable number of resource units when data is not transmitted, and (ii) a fixed or variable number of resource units when data is transmitted. The number of resource units used for the control channel may be different from that shown in fig. 7A to 7D.

In general, the variable control channel has a different structure depending on one or more of the following factors:

● system configuration, e.g., downlink and uplink allocations, e.g., number of downlink subframes and number of uplink subframes;

● UE configuration, e.g., downlink and uplink subframes applicable to the UE;

● amount of resources available for control channels;

● type of control information to be sent on the control channel, e.g., CQI and/or ACK information;

● amount of each type of control information to be sent, e.g., number of HARQ processes acknowledged;

●, which may determine the size and location of the control channel; and

● expected reliability of each type of control information.

The variable control channel may support transmission of one or more types of control information with a variable amount of resources. Different structures for mapping control information to control channel resources are used, depending on various factors such as those given above. Accordingly, the structure of the control channel may vary depending on various factors.

Fig. 8 shows a design of a process 800 for sending control information. Process 800 may be performed by a UE in the uplink (as described above) or by a node B in the downlink. At least one type of control information to be transmitted may be determined (block 812). The control information to be transmitted may include only CQI information, only ACK information, both CQI and ACK information, and/or other types of control information. The structure of the control channel is determined based on the operational configuration and/or the factors described above (block 814). The operating configuration is determined based on the system configuration (e.g., asymmetry of downlink and uplink allocations), the UE configuration (e.g., applicable downlink and uplink subframes), and so on. A variety of structures may be supported for the control channel, some examples of which are given in fig. 7A to 7D. A supported structure is selected based on the operating configuration and/or other factors. (i) If no data is sent, the control channel may include a fixed amount of resources from the control segment; or (ii) if data is transmitted, the control channel may include a variable amount of resources from the data segment. The control segment and the data segment may occupy different frequency locations.

Based on the structure, at least one type of control information is mapped to resources of the control channel (block 816). The control channel resources may include time resources, frequency resources, code resources, and the like, or any combination thereof. Based on this structure, each type of control information may be mapped to a respective portion of the control channel resources. For example, as shown in structure 720 in fig. 7B and structure 740 in fig. 7D, only CQI information may be transmitted and mapped to all control channel resources. For example, as shown by structures 712 through 716 in fig. 7A and structures 732 through 736 in fig. 7C, only ACK information may be sent and mapped to all control channel resources. Based on the structure (e.g., as shown by structures 722 through 726 in fig. 7B and structures 742 through 746 in fig. 7D), both CQI and ACK information may be sent and mapped to resources of the control channel.

Fig. 9 shows a design of an apparatus 900 for transmitting control information. The apparatus 900 comprises: means for determining at least one type of control information to transmit (block 912); a module that determines a structure of a control channel based on an operating configuration (e.g., asymmetry of downlink and uplink allocations) and/or other factors (block 914); and means for mapping at least one control information to resources of a control channel based on the structure (block 916).

FIG. 10 shows a design of a process 1000 for receiving control information. Process 1000 may be performed by a node B on the uplink or a UE on the downlink (as described above). At least one type of control information to be received may be determined (block 1012). The structure of the control channel is determined based on the operating configuration (which may indicate asymmetry of the downlink and uplink allocations) and/or other factors (block 1014). Based on the structure, at least one type of control information is received from resources of a control channel (block 1016). For example, based on this configuration, CQI information, or ACK information, or both CQI information and ACK information are received from the resources of the control channel.

Fig. 11 shows a design of an apparatus 1100 for receiving control information. The apparatus 1100 comprises: means for determining at least one type of control information to receive (block 1112); a module that determines a structure of a control channel based on an operational configuration and/or other factors (block 1114); and a module for receiving at least one control information from a resource of the control channel based on the structure (block 1116).

The modules in fig. 9 and 11 may comprise processors, electronics devices, hardware devices, electronics components, logical circuits, memories, etc., or any combination thereof.

Fig. 12 shows a block diagram of a design of node B110 and UE120, which are one of the node bs and one of the UEs in fig. 1. At UE120, a Transmit (TX) data and control processor 1210 receives Uplink (UL) data from a data source (not shown) and/or control information from a controller/processor 1240. A processor 1210 processes (e.g., formats, codes, interleaves, and symbol maps) the data and control information and provides modulation symbols. A Modulator (MOD)1220 processes the modulation symbols as described below and provides output chips. A transmitter (TMTR)1222 may process (e.g., convert to analog, amplify, filter, and upconvert) the output chips and generate an uplink signal, which is transmitted via an antenna 1224.

At node B110, an antenna 1252 may receive the uplink signals from UE120 and the other UEs and provide a received signal to a receiver (RCVR) 1254. Receiver 1254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal and provide received samples. A demodulator (DEMOD)1260 processes the received samples as described below and provides demodulated symbols. A Receive (RX) data and control processor 1270 may process (e.g., symbol demap, deinterleave, and decode) the demodulated symbols to obtain decoded data and control information for UE120 and other UEs.

On the downlink, at node B110, Downlink (DL) data and control information to be transmitted to the UE may be processed by a TX data and control processor 1290, modulated by a modulator 1292 (e.g., OFDM), conditioned by a transmitter 1294, and transmitted via antenna 1252. At UE120, the downlink signals from node B110 and possibly other node bs may be received by antennas 1224, conditioned by receivers 1230, demodulated by a demodulator 1232 (e.g., OFDM), and processed by a RX data and control processor 1234 to recover the downlink data and control information transmitted by node B110 to UE 120. In general, the processing for uplink transmissions may be the same or different than the processing for downlink transmissions.

Controllers/processors 1240 and 1280 may control the operation at UE120 and node B110, respectively. Memories 1242 and 1282 may store data and program codes for UE120 and node B110, respectively. A scheduler 1284 may schedule UEs for downlink and/or uplink transmission and provide assignments of system resources (e.g., assignments of subcarriers for downlink and/or uplink) to the scheduled UEs.

Fig. 13 shows a block diagram of a design of modulator 1220a for control information. Modulator 1220a may be used for modulator 1220 for UE120 in fig. 12 when not transmitting data.

TX control processor 1310, which is part of TX data and control processor 1210 in fig. 12, may receive and process CQI and/or ACK information to be sent in a subframe. In one design, if only ACK information is sent in a given time slot, TX control processor 1310 may generate modulation symbols for the ACK/NAK for each HARQ process by, for example, mapping the ACK to one QPSK value (e.g., 1+ j) and the NAK to another QPSK value (e.g., -1-j). Processor 1310 may then repeat the QPSK symbols for each HARQ process to obtain L modulation symbols for L symbol periods in a slot, and may provide one modulation symbol in each symbol period. If only CQI information is sent in a given time slot, TX control processor 1310 may encode the CQI information based on a block code to obtain a plurality of code bits, map the plurality of code bits to L modulation symbols, and provide one modulation symbol in each symbol period. If both CQI and ACK information are sent in a given time slot, TX control processor 1310 may jointly encode the CQI and ACK information based on another block code to obtain a plurality of code bits, map the plurality of code bits to L modulation symbols, and provide one modulation symbol in each symbol period. In another design, processor 1310 may process the CQI and ACK information separately and provide two modulation symbols for CQI and ACK for 2 VFRs S1 and S2 in each symbol period (as shown in FIGS. 7A and 7B). TX control processor 110 may also generate modulation symbols for CQI and/or ACK in other manners.

A unit 1322 may receive a modulation symbol for CQI and/or ACK, e.g., one or two modulation symbols, from TX control processor 1310 in each symbol period at modulator 1220 a. For each modulation symbol, unit 1322 may modulate a CAZAC (constant amplitude zero autocorrelation) sequence with the modulation symbol to obtain a corresponding modulated CAZAC sequence with the modulated symbol. A CAZAC sequence is a sequence having good temporal characteristics (e.g., a constant time-domain envelope) and good spectral characteristics (e.g., a smooth spectrum). Some exemplary CAZAC sequences include Chu sequences, Zadoff-Chu sequences, Frank sequences, Generalized Chirp (GCL) sequences, Golomb sequences, P1, P3, P4, and Px sequences, among others, as known in the art. In each symbol period, unit 1322 may provide M modulated symbols for the M subcarriers in the control segment assigned to UE 120.

A spectral shaping unit 1330 may perform spectral shaping on the M modulated symbols in each symbol period and provide M spectrally shaped symbols. A symbol-to-subcarrier mapping unit 1332 maps the M spectrally shaped symbols to M subcarriers in the control segment allocated to UE120 and maps zero symbols with a signal value of zero to the remaining subcarriers. An Inverse Discrete Fourier Transform (IDFT) unit 1334 may receive N mapped symbols for a total of N subcarriers from mapping unit 1332, perform an N-point IDFT on the N symbols to convert the symbols from the frequency domain to the time domain, and provide N time-domain output chips. Each output chip is a complex value to be transmitted in one chip period. A parallel-to-serial converter (P/S)1336 may serialize the N output chips and provide the useful portion of the SC-FDM symbol. Cyclic prefix generator 1338 may copy the last C output chips of the useful portion and append them to the front of the useful portion to form an SC-FDM symbol containing N + C output chips. The cyclic prefix is used to combat inter-symbol interference (ISI) caused by frequency selective fading. The SC-FDM symbol may be transmitted in one SC-FDM symbol period equal to N + C chip periods.

Fig. 14 shows a block diagram of a design of modulator 1220b for data and control information. Modulator 1220b may be used as modulator 1220 in fig. 12 when transmitting data. TX control processor 1310 may process the control information and provide modulation symbols for the control information to modulator 1220 b. TX data processor 1312, which is part of TX data and control processor 1210 in fig. 12, may receive data to be transmitted, encode the data based on a coding scheme to obtain code bits, interleave the code bits, and map the interleaved bits to modulation symbols based on a modulation scheme.

In modulator 1220b, a serial-to-parallel converter (S/P)1326 may receive modulation symbols from TX control processor 1310 and modulation symbols from TX data processor 1312. S/P1326 may provide Q modulation symbols in each symbol period, where Q is the number of subcarriers in the data section allocated to UE 120. A Discrete Fourier Transform (DFT) unit 1328 may perform a Q-point DFT on the Q modulation symbols to convert the symbols from the time domain to the frequency domain and provide Q frequency domain symbols. A spectral shaping unit 1330 performs spectral shaping on the Q frequency-domain symbols and provides Q spectrally shaped symbols. A symbol-to-subcarrier mapping unit 1332 maps the Q spectrally shaped symbols to the Q subcarriers in the data segment and maps zero symbols to the remaining subcarriers. IDFT unit 1334 performs an N-point IDFT on the N mapped symbols of unit 1332 and provides N time-domain output chips. P/S1336 serializes the N output chips and cyclic prefix generator 1338 may append a cyclic prefix to form an SC-FDM symbol containing N + C output chips.

Fig. 13 and 14 show exemplary designs for transmitting control information without data and with data, respectively. The control information may also be transmitted in various other ways. In another design, when only control information is sent, the CQI and/or ACK information is separately encoded, multiplexed, converted by DFT, and mapped to subcarriers of the control segment, similar to the design shown in fig. 14. In another design, the CQI and/or ACK information may be jointly coded, multiplexed, converted by DFT, and mapped to subcarriers of the control segment. In addition to the design shown in fig. 14, control information and data are transmitted based on other designs.

In the designs shown in fig. 13 and 14, control information may be processed based on a first processing scheme when data is not transmitted and may be processed based on a second processing scheme when data is transmitted. When transmitting alone, the control information may be transmitted using a CAZAC sequence to achieve lower PAR. When transmitted with data, control information may be multiplexed with the data and processed in a similar manner to the data. The control information may also be processed in other ways. For example, the control information may also be transmitted using CDM (e.g., spreading each modulation symbol of the control information by an orthogonal code and mapping the spread modulation symbols to resources of a control channel).

Fig. 15 shows a block diagram of a design of demodulator 1260 of node B110 in fig. 12. Within demodulator 1260, a cyclic prefix removal unit 1510 may take N + C received samples in each SC-FDM symbol period, remove C received samples corresponding to the cyclic prefix, and provide N received samples for the useful portion of the received SC-FDM symbol. S/P1512 may provide N received samples in parallel. DFT unit 1514 may perform an N-point DFT on the N received samples and provide N received symbols for the N total subcarriers. The N received symbols may include data and control information sent by all UEs to node B110. The following describes a process of recovering control information and/or data from the UE 120.

If the UE120 transmits control information and data, the symbol-subcarrier demapping unit 1516 provides Q received symbols of Q subcarriers in the data segment allocated to the UE120 and discards the remaining received symbols. Unit 1518 scales the Q received signals according to the spectral shaping performed by UE 120. Unit 1518 may also perform data detection (e.g., matched filtering, equalization, etc.) on the Q scaled symbols via channel gain estimates and provide Q detected symbols. IDFT unit 1520 may perform a Q-point IDFT on the Q detected symbols and provide Q demodulated symbols for data and control information. P/S1522 may provide demodulated symbols for data to RX data processor 1550 and demodulated symbols for control information to a multiplexer (Mux)1532, which may provide the symbols to RX control processor 1552. Processors 1550 and 1552 are part of RX data and control processor 1270 in fig. 12. RX data processor 1550 may process (e.g., symbol demap, deinterleave, and decode) the demodulated symbols for the data and provide decoded data. RX control processor 1552 may process the demodulated symbols for control information and provide decoded control information, e.g., CQIs and/or ACKs.

If the UE120 transmits control information without transmitting data, the symbol-subcarrier demapping unit 1516 provides M received symbols of the M subcarriers allocated to the control segment of the UE120 and discards the remaining received symbols. Based on the M received symbols for one symbol period, CAZAC sequence detector 1530 may detect one or more modulation symbols that are most likely to have been transmitted in the symbol period. Detector 1530 may provide demodulated symbols for control information, which may be routed through a multiplexer 1532 and provided to a RX control processor 1552.

It is to be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. It is to be understood that the specific order or hierarchy of steps in the processes may be rearranged based on design preferences while remaining within the scope of the present invention. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limiting with respect to the specific order or hierarchy presented.

Those of skill in the art would 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 embodiments disclosed 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 embodiments disclosed 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 embodiments disclosed herein 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. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. Of course, the processor and the storage medium may reside as discrete components in a user terminal.

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

Claims (39)

1. An apparatus for wireless communication, comprising:

at least one processor configured for:

determining at least one type of control information to be transmitted for a subframe of a plurality of subframes,

determining a structure of a control channel of the subframe, the structure defining how to map each type of control information to a set of virtual frequency resources of the subframe, wherein the set of virtual frequency resources spans M predetermined number of contiguous subcarriers of an uplink carrier comprising N total subcarriers, wherein M is less than N, wherein the structure is selected from a plurality of structures according to the at least one type of control information, and wherein each structure of the plurality of structures maps one or more types of control information to the set of virtual frequency resources of the subframe;

mapping each of the at least one type of control information to a designated portion of the set of virtual frequency resources of the control channel of the subframe based on the structure;

mapping the set of virtual frequency resources of the control channel to physical resources of an uplink carrier of the subframe, wherein mapping the set of virtual frequency resources to the physical resources of the uplink carrier comprises mapping the set of virtual frequency resources to a control segment formed at an edge of a system bandwidth of the uplink carrier; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to: the method comprises processing the at least one control information to obtain modulation symbols, modulating a CAZAC (constant amplitude zero autocorrelation) sequence by each modulation symbol to obtain a corresponding modulated CAZAC sequence, and mapping the modulated CAZAC sequence for the modulation symbols to resources of the control channel.

3. The apparatus of claim 1, wherein the at least one type of control information to be transmitted comprises only Channel Quality Indicator (CQI) information, and wherein the at least one processor is configured to map the CQI information to all of the set of virtual frequency resources of the control channel.

4. The apparatus of claim 1, wherein the at least one type of control information to be transmitted comprises only Acknowledgement (ACK) information, and wherein the at least one processor is configured to map the ACK information to all of the set of virtual frequency resources of the control channel.

5. The apparatus of claim 1, wherein the at least one processor is configured to determine the structure of the control channel further based on a control information amount for each type of control information to be transmitted.

6. The apparatus of claim 1, wherein at least one processor is configured to determine the structure of the control channel further based on a system configuration, or a User Equipment (UE) configuration, or both.

7. The apparatus of claim 6, wherein the system configuration represents downlink and uplink allocations, and wherein the at least one processor is configured to: determining a structure of the control channel based on asymmetry of the allocation of the downlink and uplink.

8. The apparatus of claim 6, wherein the at least one processor is configured to: determining a structure of the control channel based on a number of subframes allocated for downlink and a number of subframes allocated for uplink indicated by the system configuration.

9. The apparatus of claim 1, wherein the at least one type of control information to be transmitted comprises Channel Quality Indicator (CQI) and Acknowledgement (ACK) information, and wherein the at least one processor is configured to map the CQI and the ACK information to the set of virtual frequency resources of the control channel based on the structure.

10. The apparatus of claim 1, wherein the set of virtual frequency resources of the control channel is mapped to at least one set of contiguous subcarriers in at least one slot of the physical resources.

11. The apparatus of claim 1, wherein a modulation order for modulation symbols mapped to the set of virtual frequency resources is determined based on a number of bits of the control information.

12. The apparatus of claim 1, wherein the at least one processor is configured to map the set of virtual frequency resources of the control channel to a first set of contiguous subcarriers in a first slot of the physical resources and a second set of contiguous subcarriers in a second slot of the physical resources.

13. The apparatus of claim 1, wherein the at least one type of control information to be transmitted comprises Acknowledgement (ACK) information, and wherein the at least one processor is configured to determine the structure of the control channel based on a number of hybrid automatic repeat request (HARQ) processes to be acknowledged by the ACK information.

14. The apparatus of claim 1, wherein the at least one type of control information to be transmitted comprises Channel Quality Indicator (CQI) information and Acknowledgement (ACK) information, and wherein the at least one processor is configured to map CQI information to a first portion of the set of virtual frequency resources of the control channel and to map ACK information to a second portion of the set of virtual frequency resources of the control channel.

15. The apparatus of claim 1, wherein the at least one processor is configured to map the set of virtual frequency resources of the control channel to all subcarriers within a control segment in at least one slot of the physical resources.

16. The apparatus of claim 1, wherein the at least one type of control information to be transmitted comprises Channel Quality Indicator (CQI) information, and wherein the at least one processor is configured to:

encoding the CQI information using a block code to obtain encoded bits; and

mapping the coded bits to L modulation symbols; and

mapping each of the L modulation symbols to a set of virtual frequency resources for one symbol period of the subframe.

17. The apparatus of claim 11, in which the at least one processor is further configured to repeat modulation symbols for each of L symbol periods of the control channel of the subframe.

18. A method for wireless communication, comprising:

determining at least one type of control information to be transmitted for a subframe of a plurality of subframes;

determining a structure of a control channel of the subframe, the structure defining how to map each type of control information to a set of virtual frequency resources of the subframe, wherein the set of virtual frequency resources spans M predetermined number of contiguous subcarriers of an uplink carrier comprising N total subcarriers, wherein M is less than N, wherein the structure is selected from a plurality of structures according to the at least one type of control information, and wherein each structure of the plurality of structures maps one or more types of control information to the set of virtual frequency resources of the subframe;

mapping each of the at least one type of control information to a designated portion of the set of virtual frequency resources of the control channel of the subframe based on the structure; and

mapping the set of virtual frequency resources of the control channel to physical resources of an uplink carrier of the subframe, wherein mapping the set of virtual frequency resources to the physical resources of the uplink carrier comprises mapping the set of virtual frequency resources to a control segment formed at an edge of a system bandwidth of the uplink carrier.

19. The method of claim 18, wherein the at least one type of control information to be transmitted comprises Acknowledgement (ACK) information, and wherein the determining the structure of the control channel comprises determining the structure of the control channel further based on a number of hybrid automatic repeat request (HARQ) processes to be acknowledged by the ACK information.

20. The method of claim 18, wherein the at least one control information to be transmitted comprises only Channel Quality Indicator (CQI) information, or only Acknowledgement (ACK) information, or both CQI and ACK information, and wherein the mapping the at least one control information comprises mapping the CQI information, or the ACK information, or both the CQI and the ACK information to the set of virtual frequency resources of the control channel based on the structure.

21. The method of claim 18, wherein the set of virtual frequency resources of the control channel is mapped to at least one set of contiguous subcarriers in at least one slot of the physical resources.

22. The method of claim 18, wherein the determining the structure of the control channel is further based on a system configuration, or a User Equipment (UE) configuration, or both, wherein the system configuration represents downlink and uplink allocations, and wherein the determining the structure of the control channel comprises determining the structure of the control channel based on asymmetry of the downlink and uplink allocations.

23. The method of claim 18, wherein the set of virtual frequency resources of the control channel is mapped to a first set of contiguous subcarriers in a first time slot of the physical resources and a second set of contiguous subcarriers in a second time slot of the physical resources.

24. The method of claim 18, wherein the set of virtual frequency resources of the control channel is mapped to all subcarriers within a control segment in at least one slot of the physical resources.

25. The method of claim 18, wherein a modulation order for the modulation symbols mapped to the set of virtual frequency resources is determined based on a bit number of the control information.

26. The method of claim 18, wherein the at least one type of control information to be transmitted comprises Channel Quality Indicator (CQI) information, the method further comprising:

encoding the CQI information using a block code to obtain encoded bits; and

mapping the coded bits to L modulation symbols; and

mapping each of the L modulation symbols to a set of virtual frequency resources for one symbol period of the subframe.

27. The method of claim 25, further comprising:

repeating the modulation symbol for each of L symbol periods of the control channel of the subframe.

28. An apparatus for wireless communication, comprising:

means for determining at least one type of control information to be transmitted for a subframe of a plurality of subframes;

means for determining a structure of a control channel of the subframe, the structure defining how to map each type of control information to a set of virtual frequency resources of the subframe, wherein the set of virtual frequency resources spans M predetermined number of contiguous subcarriers in an uplink carrier comprising a total of N subcarriers, wherein M is less than N, wherein the structure is selected from a plurality of structures according to the at least one type of control information, and wherein each structure of the plurality of structures maps one or more types of control information to the set of virtual frequency resources of the subframe;

means for mapping each of the at least one type of control information to a designated portion of the set of virtual frequency resources of the control channel of the subframe based on the structure; and

means for mapping the set of virtual frequency resources of the control channel to physical resources of an uplink carrier of the subframe, wherein mapping the set of virtual frequency resources to the physical resources of the uplink carrier comprises mapping the set of virtual frequency resources to a control segment formed at an edge of a system bandwidth of the uplink carrier.

29. The apparatus of claim 28, wherein the means for determining the structure of the control channel determines the structure of the control channel further based on a system configuration, a User Equipment (UE) configuration, or both, wherein the system configuration represents downlink and uplink allocations, and wherein the means for determining the structure of the control channel comprises means for determining the structure of the control channel based on an asymmetry of the downlink and uplink allocations.

30. The apparatus of claim 28, wherein the at least one type of control information to be transmitted comprises Acknowledgement (ACK) information, and wherein the means for determining the structure of the control channel comprises means for determining the structure of the control channel based further on a number of hybrid automatic repeat request (HARQ) processes to be acknowledged by the ACK information.

31. The apparatus of claim 28, wherein the at least one type of control information to be transmitted comprises only Channel Quality Indicator (CQI) information, or only Acknowledgement (ACK) information, or both CQI and ACK information, and wherein the means for mapping the at least one type of control information comprises means for mapping the CQI information, or the ACK information, or both CQI and ACK information to the set of virtual frequency resources of the control channel based on the structure.

32. An apparatus for wireless communication, comprising:

at least one processor configured to:

determining at least one type of control information to be received for a subframe of a plurality of subframes;

determining a structure of control channels of a plurality of subframes, the structure defining how to map each type of control information to a set of virtual frequency resources of the subframe, wherein the set of virtual frequency resources spans M predetermined number of contiguous subcarriers of an uplink carrier comprising N total subcarriers, wherein M is less than N, wherein the structure is selected from a plurality of structures according to the at least one type of control information, and wherein each structure of the plurality of structures maps one or more types of control information to the set of virtual frequency resources of the subframe;

receiving the set of virtual frequency resources of the control channel by demapping received physical resources of an uplink carrier of the subframe, wherein demapping the received physical resources of the uplink carrier includes demapping a control segment to be formed at an edge of a system bandwidth of the uplink carrier; and

receiving each of the at least one type of control information from a designated portion of the set of virtual frequency resources of the control channel of the subframe based on the structure; and

a memory coupled to the at least one processor.

33. The apparatus of claim 32, wherein the at least one type of control information to be received comprises Acknowledgement (ACK) information, and wherein the at least one processor is configured to determine the structure of the control channel further based on a number of hybrid automatic repeat request (HARQ) processes to be acknowledged by the ACK information.

34. The apparatus of claim 32, wherein the at least one type of control information to be received comprises only Channel Quality Indicator (CQI) information, or only Acknowledgement (ACK) information, or both CQI and ACK information, and wherein the at least one processor is configured to receive the CQI information, or the ACK information, or both CQI and ACK information from the set of virtual frequency resources of the control channel based on the structure.

35. The apparatus of claim 32, wherein the at least one processor is configured to determine the structure of the control channel further based on a system configuration, wherein the system configuration represents downlink and uplink allocations, or a User Equipment (UE) configuration, or both.

36. A method for wireless communication, comprising:

determining at least one type of control information to be received for a subframe of a plurality of subframes;

determining a structure of a control channel of the subframe, the structure defining how to map each type of control information to a set of virtual frequency resources of the subframe, wherein the set of virtual frequency resources spans M predetermined number of contiguous subcarriers of an uplink carrier comprising N total subcarriers, wherein M is less than N, wherein the structure is selected from a plurality of structures according to the at least one type of control information, and wherein each structure of the plurality of structures maps one or more types of control information to the set of virtual frequency resources of the subframe;

receiving the set of virtual frequency resources of the control channel by demapping received physical resources of an uplink carrier of the subframe, wherein demapping the received physical resources of the uplink carrier includes demapping the set of virtual frequency resources from a control segment formed at an edge of a system bandwidth of the uplink carrier; and

receiving each of the at least one type of control information from a designated portion of the set of virtual frequency resources of the control channel of the subframe based on the structure.

37. The method of claim 36, wherein the determining the structure of the control channel comprises determining the structure of the control channel further based on a system configuration, or a User Equipment (UE) configuration, or both, wherein the system configuration represents downlink and uplink allocations.

38. An apparatus for wireless communication, comprising:

means for determining at least one type of control information to be received for a subframe of a plurality of subframes;

means for determining a structure of a control channel of the subframe, the structure defining how to map each type of control information to a set of virtual frequency resources of the subframe, wherein the set of virtual frequency resources spans M predetermined number of contiguous subcarriers in an uplink carrier comprising a total of N subcarriers, wherein M is less than N, wherein the structure is selected from a plurality of structures according to the at least one type of control information, and wherein each structure of the plurality of structures maps one or more types of control information to the set of virtual frequency resources of the subframe;

means for receiving the set of virtual frequency resources of the control channel by demapping received physical resources of an uplink carrier of the subframe, wherein demapping the received physical resources of the uplink carrier comprises demapping the set of virtual frequency resources from a control segment formed at an edge of a system bandwidth of the uplink carrier; and

means for receiving each of the at least one type of control information from a designated portion of the set of virtual frequency resources of the control channel of the subframe based on the structure.

39. The apparatus of claim 38, wherein the means for determining the structure of the control channel determines the structure of the control channel further based on a system configuration, or a User Equipment (UE) configuration, or both, wherein the system configuration represents downlink and uplink allocations.