RU2378764C2 - Assymetrical operation mode in multi-carrier communication systems - Google Patents

Abstract

FIELD: physics; communications.

SUBSTANCE: method and system for providing assymetrical operation modes in multi-carrier wireless communication systems are proposed. The method can assign a long code mask (LCM) in an information channel associated with several carriers in a direct communication line for transmitting data from an access network to an access terminal; and multiplex this information channel on a return communication line carrier. This information channel can contain one of data source channel (DSC) information, data rate control (DRC) and acceptance acknowledgement (ACK), and multiplexing can be code division multiplexing (CDM). The access network (AN) can notify the access terminal (AT) whether DSC information should be multiplexed, based on feedback from the AT. The method can further shift ACK information in the return communication line to reduce the peak value of the return communication line to a mean value, carry out CDM of the information channel into I-branches and Q-branches, and transmit the code division multiplexed channel at the return communication line carrier.

EFFECT: efficiency and reliability of a multi-carrier communication system.

31 cl, 26 dwg

Description

This application claims the priority of the jointly assigned provisional US patent application No. 60 / 701,206, entitled "Asymmetric Multiple Carrier Communication Systems" filed July 20, 2005, and the jointly assigned provisional US patent application No. 60 / 709,944, entitled "Asymmetric Operating Mode Multiple Carrier Communication Systems ”filed August 18, 2005, both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention, in General, relates to wireless communication systems and, in particular, to communication systems with multiple carriers, providing asymmetric modes of operation.

BACKGROUND

A communication system may provide communication between a number of base stations and access terminals. The forward link or downlink refers to transmission from the base station to the access terminal. A reverse link or an uplink refers to transmission from an access terminal to a base station. Each access terminal can communicate with one or more base stations on the forward and reverse links at the moment, depending on whether the access terminal is active and whether the access terminal is in flexible handoff mode.

Radio communication systems are widely used to provide various types of communication (eg, voice, data, etc.) for a variety of users. Such systems can be based on code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), or other multiple access methods. CDMA systems offer some desirable features, including increased system throughput. A CDMA system can be designed to implement one or more standards, such as IS-95, cdma2000, IS-856, W-CDMA, TD-SCDMA, and other standards.

In response to the growing demand for multimedia services and high data rate data, multi-carrier modulation has been proposed in wireless communication systems. So, for example, it remains a difficult task to provide efficient and reliable multicarrier communication systems.

SUMMARY OF THE INVENTION

Method and system for providing asymmetric operating modes in multi-carrier radio communication systems. In one mode, the method may assign a long code mask (LCM) to an information channel associated with multiple forward link carriers to transmit data from a base station or access network to an access terminal, and multiplex the information channel on a reverse link carrier. The information channel may comprise at least one of data source channel information (DSC), data rate control information (DRC), and acknowledgment information (ACK), wherein the multiplexing may be code division multiplexing (CDM). The access network may instruct the access terminal whether to multiplex DSC information or not. In cases where the feedback from the access terminal is received on the same channel card and the serving sector is the same for multiple forward link carriers, the access network may instruct the access terminal not to multiplex the DSC information. This method may further bias the ACK information in the reverse link to reduce peak values of the reverse link to an average value. In another mode, the method may code-multiplex the information channel on the I-branch and Q-branches and transmit the code-multiplexed information channel on the reverse link carrier. The DRC and ACK information can be masked by Walsh codes, and the DRC information can be further combined with DRC masking characters that are offset by Walsh codes in both the I-branch and the Q-branch.

Depending on the equipment, any combination of modes can be supported. The first mode can implement 15 forward link carriers and one reverse link carrier with 15 unique long code masks assigned to the access terminal. The first and second modes can also be combined to implement 15 forward link carriers and one reverse link carrier with 4 unique long code masks assigned to the access terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, nature and advantages of the present invention may be more apparent from the detailed description set forth below together with the drawings. The same reference numbers and symbols may identify the same or similar objects.

Figure 1 illustrates a wireless communication system with base stations and access terminals.

Figure 2 illustrates an example of a symmetric assignment of carriers of the forward link and reverse link.

3A and 3B illustrate examples of asymmetric carrier assignment.

4A illustrates an example reverse link rate control (DRC) transmission for a single forward link carrier.

4B-4F illustrate examples of multi-carrier time division multiplexed DRCs.

Figure 5 illustrates a block diagram of a module that can be used to transmit DRC and ACK channels for additional FL carriers on the primary RL using a separate long code mask.

6 illustrates the reduction of the peak value to the average value in asymmetric mode of operation and using a long code mask.

7A and 7B illustrate an example of an access terminal sending two DRC channel transmission requests to a base station for two forward link carriers for transmitting data at two different speeds.

7C and 7D illustrate a base station transmitting subpackets of a forward traffic channel on two forward link carriers at two different speeds.

7E illustrates an access terminal sending acknowledgment (ACK) and negative acknowledgment (NAK) in a single reverse link channel for these two forward link carriers.

8 and 9 illustrate processes and structures for an asymmetric multi-carrier ACK transmission mode.

10 and 11 illustrate the processes and structures of an asymmetric multicarrier DRC transmission mode.

12 illustrates the correspondence between forward link frequencies and reverse link frequencies in a multi-carrier system.

FIG. 13A illustrates an example of a direct link transmission path, structure, or process that may be implemented in the base station of FIG.

FIG. 13B illustrates an example of a path, process, or structure for receiving a forward link that may be implemented in the access terminal of FIG. 1.

Fig. 14 illustrates some components of the access terminal of Fig. 1.

DETAILED DESCRIPTION

Any embodiment described herein is not necessarily preferred or advantageous over other embodiments. Although various aspects of the present disclosure are presented in the drawings, these drawings are not necessarily shown to scale or shown in detail.

1 illustrates a wireless communication system 100 that includes a system controller 102, base stations (BSs) 104a-104b, and multiple access terminals (ATs) 106a-106h. This system 100 may have any number of controllers 102, base stations 104, and access terminals 106. Various aspects and embodiments of the present invention described below can be implemented in the system 100.

Access terminals 106 may be mobile or stationary and may be dispersed throughout the communication system 100 of FIG. 1. The access terminal 106 may be connected to or implemented in a computer device, such as a personal computer - laptop. Alternatively, the access terminal may be a separate data device, such as a personal digital assistant (PDA). Access terminal 106 may relate to various types of devices, such as a wired telephone, a cordless telephone, a cell phone, a laptop, a wireless personal computer (PC) card, a PDA, an external or internal modem, etc. An access terminal may be any device that provides data connectivity for a user by communicating via a wireless channel or through a wired channel, for example using fiber optic or coaxial cables. An access terminal may have various names, such as a mobile station (MS), an access device, a subscriber device, a mobile device, a mobile terminal, a mobile phone, a remote station, a remote terminal, a remote device, a user device, user equipment, a portable device, etc. d.

System 100 provides communications for a number of cells, where each cell is served by one or more base stations 104. Base station 104 may also be referred to as a transceiver base station (BTS), an access node, portions of an access network (AN), a transceiver pool modems (MPT) or Node B. An access network refers to network equipment that provides connectivity between a switched packet data network (eg, the Internet) and access terminals 106.

A forward link (FL) or downlink refers to transmission from a base station 104 to an access terminal 106. A reverse link (RL) or uplink refers to transmission from an access terminal 106 to a base station 104.

Base station 104 may transmit data to access terminal 106 using a data rate selected from a set of different data rates. Access terminal 106 may measure the signal-to-noise and interference (SINR) ratio of the pilot sent by base station 104 and determine a desired data rate for base station 104 to transmit data to access terminal 106. Access terminal 106 may send data request channel or data rate control (DRC) messages to base station 104 to inform base station 104 of the desired data rate.

A system controller 102 (also referred to as a base station controller (BSC)) can coordinate and control the base stations 104 and can further control the routing of calls from access terminals 106 through the base stations 104. The system controller 102 can be further connected to a public switched telephone network (PSTN) through a mobile switching center (MSC) and with a packet data network through a packet data service node (PDSN).

The communication system 100 may use one or more communication methods, such as code division multiple access (CDMA), IS-95, high-speed packet data (HRPD), also referred to as high-speed data (HDR), as defined by “cdma2000 High Rate Packet Data Air Interface Specification »TIA / EIA / IS-856, CDMA 1xEV-DV (1x evolution, optimized data), W-CDMA (Broadband CDMA), UMTS (Universal Mobile Telecommunication System), TD-SCDMA (Synchronous Time Division) CDMA), OFDM (Orthogonal Frequency Separation), etc. The examples described below provide details for clarity of understanding. The ideas presented here also apply to other systems, and these examples are not intended to limit the present application.

Multi-carrier system

The multi-carrier system described herein may utilize frequency division multiplexing in which each “carrier” corresponds to the radio frequency range. For example, a carrier may have a width of 1.25 megahertz, but other sizes of carriers may be used. The carrier may also be called a CDMA carrier, a link, or a CDMA channel.

Data flow requirements may be biased towards more intensive use of the forward or reverse links. The description below relates to the separation of assignments of the forward link and reverse link in a multi-carrier radio communication system. System 100 may assign M forward links (or carriers) and N reverse links (or carriers) to access terminal 106, where M and N may not be equal. The description below describes overhead transmission mechanisms to reduce reverse link overhead.

BSC or MSC base stations may determine a number of FL carriers assigned to an access terminal. BSC or MSC base stations can also change the number of FL carriers assigned to the access terminal depending on conditions such as channel conditions, available data for the terminal, maximum range of terminal power amplifier, and application streams.

Access terminals 106 may execute applications such as an Internet application, video conferencing, movies, games, etc. that can use voice, image files, video clips, data files, etc., transmitted from base stations 104. These Applications can contain two types:

1. Allowable for delay, with high throughput of the forward link and low throughput of the reverse link; and

2. Delay sensitive, with low forward link throughput and low reverse link throughput.

Other types of applications may also exist.

If the system 100 uses multiple carriers on the forward link to achieve high throughput or maximize spectral efficiency, the access terminal 106 can avoid transmitting on all associated carriers on the reverse link to improve reverse link efficiency.

For type 1 applications where a slower DRC update is acceptable, access terminal 106 may:

a) transmit a continuous pilot on the primary carrier of the reverse link;

b) transmit data only on the primary carrier of the reverse link;

c) transmit a DRC for each FL carrier as time division multiplexed on the primary reverse link carrier, which implies that a slower DRC channel update is acceptable; and

d) transmit acknowledgment (ACK) or negative acknowledgment (NAK) messages for each FL carrier when required. Access terminal 106 may transmit a gated pilot signal (at the same power level as the pilot signal on the primary RL carrier) on the secondary carriers when transmitting an ACK channel, for example, a приходится segment is transmitted by ACK transmission to filter the pilot signal.

For type 1 applications, where a slower DRC update may not be valid, access terminal 106 may:

a) transmit a continuous pilot on all reverse link carriers associated with the allowed forward link carriers;

b) transmit data only on the primary carrier of the reverse link; and

c) transmit an ACK for each FL carrier when necessary.

For type 2 applications, access terminal 106 may:

a) transmit a continuous pilot on the primary carrier of the reverse link;

b) transmit data only on the primary carrier of the reverse link;

c) transmit a DRC for each FL carrier as time division multiplexed on the primary reverse link carrier, which suggests that a slower DRC channel update is acceptable; and

d) transmit ACKs only on the primary reverse link carrier.

Base station 104 may be limited by the requirement that no more than one packet is transmitted on all forward link carriers. Base station 104 may determine the associated ACKs based on the timing of the transmitted FL packet.

Alternatively, access terminal 106 may perform an alternative form of ACK channel transmission:

a) reduce ACK channel transmit time interval if desired, e.g., if the system 100 supports additional FL carriers (in an EV-DO ACK system can be transferred into _^1/2 segments);

b) ACK channel transmission for N forward link carriers in a single Ѕ segment;

c) the channel ACK transmission interval is a function of the number of allowed forward link carriers; and

d) channel ACK transmissions on the RL and FL association setting can be implemented by signaling at the medium access control (MAC) level 1400 (FIG. 14).

Multi-carrier forward traffic channel

There can be two modes of carrier assignment: symmetric carrier assignment and asymmetric carrier assignment.

FIG. 2 illustrates an example of symmetric carrier assignment with three forward link carriers 200A-200C, for example, used for EV-DO data, and three corresponding reverse link carriers 202A-202C. Symmetric carrier assignment can be used for (a) applications with symmetric data rate requirements, and / or (b) applications with asymmetric data rate requirements supported by hardware that executes a symmetric FL / RL operation.

3A and 3B illustrate examples of asymmetric carrier assignment. 3A shows three forward link carriers 300A-300C and one corresponding reverse link carrier 302. 3B shows three forward link carriers 300A-300C and two corresponding reverse link carriers 304A and 304B. Asymmetric carrier assignment can be used for applications with asymmetric data rate requirements, such as downloading the file transfer protocol (FTP). Asymmetric carrier assignment may have (a) reduced reverse link overhead and (b) MAC channels, allow separation of the forward link traffic carrier assignment from the reverse power control (RPC) carrier assignment.

Asymmetric Forward and Reverse Link Assignment - Multicarrier DRC

Access terminal 106 may time division multiplex DRC channel transmission for multiple forward link carriers on a single reverse link carrier.

FIG. 14 illustrates a time division multiplexer 1402 for multiplexing DCR information in the access terminal 106 of FIG. 1.

The MAC level 1400 (FIG. 14) at the access terminal 106 may provide a DRC association with a forward link based on the transmission time of the DRC. The number of forward link carriers (for which DRC transmissions are indicated by a single reverse link carrier) may depend on: (i) the maximum allowable DRC gap, which is the time interval required for DRC transmission for all assigned forward link carriers, for example, DRC gap = max (16 segments, DRC duration (per carrier) × number of carriers); and (ii) the number of carriers supported by hardware, such as a 1xEV-DO Rev A. channel card. In one embodiment, four FL carriers are associated with a single RL carrier, which may be limited by sending ACKs for four FL carriers.

In another embodiment, the access terminal 106 may use a single DRC channel over all carriers. In other words, the access terminal 106 sends a single DRC to the base station 104 for all of the indicated FL carriers to transmit data at the indicated DRC transmission rate to that access terminal 106.

In another embodiment, the access terminal 106 may use a combination of (a) a single DRC channel across multiple carriers (the same DRC for some FL carriers of the total number of FL carriers) and (b) a time division multiplexed DRC channel.

FIG. 4A illustrates an example reverse link DRC transmission (DRC duration = 8 segments) that requests a data rate for a single forward link carrier for use. 4B-4F illustrate examples of a plurality of time division multiplexed DRC carriers. Specifically, FIG. 4B shows an example of two DRCs (DRC duration = 4 segments each; DRC gap = 8 segments) transmitted on a single reverse link carrier for two forward link carriers. FIG. 4C shows an example of four DRCs (DRC duration = 2 segments each; DRC gap = 8 segments) transmitted on a single reverse link carrier for four forward link carriers.

Fig. 4D illustrates an example of two alternating DRCs (DRC duration = 4 segments each; DRC interval = 8 segments) transmitted on a single reverse link carrier for two forward link carriers. Alternate DRC channel transmission may provide additional temporal diversity for a given DRC duration. 4E shows an example of four alternating DRCs (DRC duration = 4 segments each; DRC gap = 16 segments) transmitted on a single reverse link carrier for four forward link carriers. FIG. 4F shows an example of four alternating DRCs (DRC duration = 2 segments each; DRC interval = 8 segments) transmitted on a single reverse link carrier for four forward link carriers.

Asymmetric assignment of the forward and reverse communication lines - ASK with many carriers

In one embodiment or a multi-carrier communication operation mode, when the number of forward link channels is greater than the number of reverse link channels, DSC, DRC and ACK channels associated with the multiple forward link channels may be multiplexed into a single reverse link carrier communication. In this embodiment or mode, a long code mask (LCM) may be used to facilitate such multiplexing. In this embodiment or AN mode, the AT may prescribe whether the DSC should be multiplexed or not. In cases where the feedback from the AT arrives at the same channel card and the serving sector is the same over the multiple carriers of the forward link, the AN may direct the AT not to multiplex the DSC. In particular, a unique long code mask can be used to transmit DRC and ACK channels for secondary forward link carriers. 5 shows a block diagram of a module that can be used to transmit DRC and ACK channels for additional forward link carriers on the primary reverse link using a separate long code mask. As a result, the maximum towards the middle of the return line can be reduced by using offset ACK channels.

Figure 6 illustrates the reduction of the peak value to the average when using an asymmetric mode of operation, for example, more than one mask of a long code. In particular, a DSC channel can be transmitted to each AT as opposed to transmission on each carrier. Since the reduction of the peak value of the reverse link to the average value can be adversely affected by the transmission of the ACK channel for secondary carriers of the forward communication line (for example, many ACK channels may become overlapping in the power graph depending on time), the DSC channel can be used to transmit the half segment of the ACK channel for secondary forward link carriers, thereby biasing the transmission of the ACK channel, as illustrated in FIG. 6. As a result, forward link demodulation and decoding time for multi-carrier ATs can be reduced for a fraction of the assigned forward link carriers.

The reduction of the peak value of the reverse link to the average is further illustrated in FIGS. 7A-7E. More specifically, the access terminal 106 may time division multiplex the ACK channel transmission for multiple forward link carriers on a single reverse link carrier, as explained below for FIG. 7E. FIG. 14 illustrates a time division multiplexer 1404 for multiplexing ACK information in the access terminal 106 of FIG. 1.

The transmission of the ACK channel to each carrier can be reduced, for example, from 1 segment to 1/4 segment (each ACK is transmitted for 1/4 segment) (instead of 1/2 segment used in EV-DO Rev. A), which can depend on a number of FL carriers for which the ACK channel is transmitted. The MAC layer 1400 (FIG. 14) at the access terminal 106 may provide for the association of an ACK with a forward link based on the transmission ACK time.

7A and 7B show an example of two DRC channel transmission requests transmitted from an access terminal 106 to a base station 104 for two forward link carriers (carriers 1 and 2) for transmitting FL data at two different speeds (e.g., 153.6 and 307.2 kbps). FIGS. 7A and 7B may show DRCs decoded by base station 104, but FIGS. 7A and 7B do not indicate the way in which DRCs are time division multiplexed on a single reverse link carrier, as in FIGS. 4B-4F.

In response to DRCs, base station 104 transmits forward traffic channel (FTC) subpackets on two forward link carriers at two different rates (e.g., 153.6 and 307.2 kbit / s) in FIGS. 7C and 7D.

Base station 104 may repeat and process the data bits of the original data packet to obtain a plurality of corresponding “subpackets” for transmission to access terminal 106. If the access terminal 106 receives a signal with a high signal to noise ratio, then the first subpacket may contain sufficient information for the access terminal 106 to decode and retrieve the original data packet. If the access terminal 106 perceives fading or a signal with a low signal to noise ratio, then the access terminal 106 may have a relatively low probability of correctly decoding and retrieving the source packet data from only the first subpacket.

If the access terminal 106 does not successfully decode the first subpacket, then the access terminal 106 sends a NAK to the base station 104. Then, the base station 104 sends a second subpacket. Access terminal 106 may combine information from the first and second subpackets to try to decode the original data packet. As the access terminal 106 receives more subpackets and combines information extracted from each received subpacket, the probability of decoding and retrieving the data of the original packet increases.

In FIG. 7C, base station 104 sends the first subpacket of the original data packet to access terminal 106 in segment 1 of carrier 1. At the same time, in FIG. 7D, base station 104 sends the first subpacket of another source data packet to access terminal 106 in segment 1 of carrier 2.

Access terminal 106 attempts to decode two source data packets from the received first subpackets on carriers 1 and 2, respectively. Access terminal 106 cannot correctly decode the received first subpacket on carrier 1; sends the NAK on the ACK channel to the base station 104 in FIG. 7E; cannot correctly decode the received second subpacket on carrier 1; sends a NAK on the ACK channel to base station 104; cannot correctly decode the received third subpacket on carrier 1; sends a NAK on the ACK channel to base station 104; correctly decodes the received fourth subpacket on carrier 1; and sends the ACK on the ACK channel to the base station 104.

Also in FIG. 7E, the access terminal 106 cannot correctly decode the first and second received subpackets on carrier 2 and sends the NAK to the base station 104. The access terminal 106 correctly decodes the original second packet (for example, using cyclic redundancy check (CRC) or another detection method errors) after receiving and processing the third subpacket in segment 3 of carrier 2. Access terminal 106 sends an acknowledgment signal (ACK) to base station 104 so as not to send a fourth subpacket for the second source packet on carrier 2.

Base station 104 can then send the first subpacket of the next packet in segment 1 (n + 12) of carrier 2. In FIG. 7E, access terminal 106 sends ACK and NAK on a single ACK / NAK RL channel for two FL carriers (1/2 channel transmission segment ACK / NAK with 1/4 segment per FL carrier).

In another embodiment, the multi-carrier ACK access terminal 106 may use a single ACL RK channel, where the ACK RL is associated with FL, based on the timing of packet reception (also called ACK channel association based on transmission time). This can be used for VoIP traffic ("Voice over Internet Protocol"). Associating an ACK channel based on transmission time may add a constraint to the FL scheduler to restrict transmission on a single FL carrier to a given access terminal 106 at any given time.

Advanced Multicarrier ACK

In another embodiment of the asymmetric multi-carrier mode, Figs. 8 and 9 illustrate processes and structures for transmitting multi-carrier ACKs and masking. In this mode, there may be 4 ACK channels for 4 forward link carriers per long code mask, for example, for transmitting ACKs on a single reverse link carrier using code division multiplexing (CDM) transmission in the I-branch and Q-branch. Various Walsh masking can be used, for example, to orthogonalize the I-branch and Q-branch. In particular, FIG. 8 shows a process and structure for preparing multi-carrier ACK transmissions. The first and second ACK signal display units 800 and 802 display or encode carrier channels 1 and 2 of the ACK channel, respectively (1 bit per segment). Then, the symbol repeat blocks 804 and 806 repeat the plurality of symbols per half segment. After the repetition, the characters are channelized by Walsh code / masking W ₁ ⁴ and W ₀ ⁴ in Walsh masking units 808 and 810, respectively, to form 32 binary symbols per half segment. The gain is then applied to each of the half segments in the ACK channel gain units 812 and 814. The half-segment amplifiers are combined into 816, and the multiplier 818 then applies the masking / Walsh code W ₁₂ ³² to indicate the ACK channel for the I phase.

Similar to FIG. 8, FIG. 9 illustrates a process and structure for transmitting multi-carrier ACKs and masking for carriers 3 and 4 of an ACK channel. The third and fourth ACK signal display units 900 and 902 display or encode carrier ACK channels 3 and 4, respectively (1 bit per segment). Then, the symbol repeat blocks 904 and 906 repeat a plurality of symbols per half segment. After the repetition, the symbols are channelized by Walsh code / masking W ₃ ⁴ and W ₂ ⁴ in Walsh masking units 908 and 910, respectively, to form 32 binary symbols in a half segment. Gains are then applied to each of the half segments in ACK channel gain units 912 and 914. The half-segment amplifiers are combined into 916, and the multiplier 918 then applies the masking / Walsh code W ₁₂ ³² to indicate the ACK channel for the Q phase.

In yet another embodiment of the asymmetric mode for multi-carrier operation, FIG. 10 illustrates a process and structure for preparing transmission of enhanced multi-carrier DRC channels. In this mode, there can be 4 DRC channels (one per forward link carrier) per long code mask, for example, to transmit the DRC transmission rate on a single reverse link carrier using code division multiplexing in the I-branch and Q-branch. For DRC transmissions using the same Walsh codeword masking, the masking DRC value for one direct carrier may be offset from the corresponding value of the other direct carrier so that the DRC masks are different. For example, if carrier # 1 uses DRC masking = 0 × 1, carrier # 3 can use the DRC mask offset value relative to 0 × 1.

More specifically, according to FIG. 10, the first and second Biorthogonal Encoders 1000 and 1002 encode DRC channels (for example, one 4-bit symbol per active segment) for each of the carriers 1 and 2, respectively, and generate 8 binary symbols per active segment . Each of the Walsh codewords masks W ₁ ² and W ₀ ² in masking units 1004 and 1006, respectively, then generates 16 binary characters per active segment. Then, the first and second signal display units 1012 and 1014 map 0 and 1 to +1 and -1 to the active segment, respectively. After gain is applied to each of the segments in the DRC channel gain units 1012 and 1014, multipliers 1020 and 1022 combine the outputs of the amplifications 1012 and 1014, respectively, with DRC masking symbols (for example, one 3-bit symbol per active segment) for carriers 1 and 2, respectively.

In another embodiment, multi-carrier asymmetric mode operations, DRC masking symbols for carriers 1 and 2 are channelized by Walsh masking units 1016 and 1018 (W _i ⁸ (i = 0.1 ... 7)), respectively. Then, the outputs of the multipliers 1020 and 1022 are added up to 1024, and then multiplied at 1026 using the Walsh mask code W ₈ ¹⁶ to indicate the DRC channel for the Q phase.

Similar to FIG. 10, FIG. 11 illustrates a process and structure for preparing the transmission of enhanced multi-carrier DRC channels for carriers 3 and 4. Third and fourth Biorthogonal Encoders 1100 and 1102 encode DRC channels (eg, one 4-bit symbol per active segment) ) for each of the carriers 3 and 4, respectively, and form 8 bit characters per active segment. Each Walsh codeword masks W ₁ ² and W ₀ ² in codeword masking units 1104 and 1106, respectively, then generates 16 binary symbols per active segment. Then, the first and second signal display units 1112 and 1114 map 0 and 1 to +1 and -1 to the active segment, respectively. After gain is applied to each of the segments in the DRC channel gain blocks 1112 and 1114, multipliers 1020 and 1022 combine the gain outputs 1112 and 1114, respectively, with DRC masking symbols (for example, one 3-bit symbol per active segment) for carriers 3 and 4, respectively.

In another embodiment, multi-carrier asymmetric mode operations, DRC masking symbols for carriers 3 and 4 are channelized by Walsh masking units (W _i ⁸ (i = 0.1 ... 7)) in masking units 1116 and 1118, respectively. Then the outputs of the multipliers 1120 and 1122 are summed up in 1124, and then multiplied at 1126 using the Walsh mask code W ₈ ¹⁶ to indicate the DRC channel for the I phase.

It will be appreciated that in any of the above embodiments of the multi-carrier asymmetric mode operation, ACK and DRC channels may be transmitted for carriers of up to four forward links on a single reverse link carrier using code division multiplexing in the I-branch and Q- branches. In the case where there are an equal number of forward link channels and reverse link channels, the aforementioned scheme may also allow the AT to autonomously turn off the pilot and traffic channels, for example, at some reverse link frequencies at which the AT decides not to transmit (for example when the AT is short of transmit power margin). In addition, for DRC transmissions using the same Walsh masking codeword, the masking DRC value for one forward link carrier may be offset from the corresponding value of the other forward forward carrier. In other words, in this aspect of the invention, ACK and DRC channels can be transmitted for the first 4 carriers using I / Q phases (common mode (I), quadrature (Q)), Walsh code component W (16.8), and I / Q phases W (16.8). If additional DRC channel transmissions are required for additional FL carriers, then access terminal 106 may use 1/2 segment DRC on each of the W phases (16.8). Thus, the access terminal 106 can support DRCs for up to 4 FL carriers through a single RL carrier.

12 shows the correspondence between the frequencies of the forward link and the frequencies of the reverse link in a multi-carrier system. A traffic channel assignment (TCA) may determine such a relationship. For example, a reverse link frequency “x” may be allocated to carry DSC, DRC, and ACK channels for all forward link frequencies.

In one aspect of the invention, a plurality (for example, up to four) of additional long code masks can be created for each reverse link frequency using the four (4) high order bits (MSBs) of the long code mask. In particular, the channel through which feedback is sent (ACK / DRC) can be identified by a 4-bit identifier, for example, <Long Code Mask Index (2 bits), Walsh Masking Feedback (1 bit), IQ Identifier (1 bit) > can be defined in TCA.

In another aspect, an AT may set long code masks for a reverse traffic channel (eg, MI _RTCMAC and MQ _RTCMAC ) as follows. For example, the 42-bit MI _RTCMAC mask associated with each Long Code Mask Index can be defined, as shown in the Table.

AN can assign one or more long code masks for the AT on each of the channels on which the AT can transmit. The long code mask for each of the channels can be identified, for example, by the index value of the long code mask, which is open data of the Route Update Protocol.

Rearranged in the Table (ATI _LCM ) can be defined as follows:

ATI _LCM = (A ₃₁ , A ₃₀ , A _29. , ... A ₀ ).

Rearranged (ATI _LCM ) =

(A _o , A ₃₁ , A ₂₂ , A ₁₃ , A ₄ , A ₂₆ , A ₁₇ , A ₈ , A ₃₀ , A ₂₁ , A ₁₂ , A ₃ , A ₂₅ , A ₁₆ A ₇ , A ₂₉ , A ₂₀ A ₁₁

A ₂ , A ₂₄ , A ₁₅ , A ₆ , A ₂₈ , A ₁₉ , A ₁₀ , A ₁ , A ₂₃ , A ₁₄ , A ₅ , A ₂₇ , A ₁₈ , A ₉ ).

The 42-bit MQ _RTCMAC mask can be obtained from the MI _RTCMAC frame as follows:

MQ _RTCMAC [k] = MI _RTCMAC [kl], for k = 1, ..., 41

MQ _RTCMAC [o] = MI _RTCMAC [0] ⊕ MI _RTCMAC [1] ⊕ MI _RTCMAC [2] ⊕

MI _RTCMAC [4] ⊕ = + MI _RTCMAC [5] ⊕

MI _RTCMAC [6] ⊕ MI _RTCMAC [9] ⊕ MI _RTCMAC [15] ⊕ MI _RTCMAC [16] ⊕

MI _RTCMAC [17] ⊕

MI _RTCMAC [18) ⊕ MI _RTCMAC [20] ⊕ MI _RTCMAC [21] ⊕ MI _RTCMAC [24] ⊕

MI _RTCMAC [25] ⊕

MI _RTCMAC [26] ⊕ MI _RTCMAC [30] ⊕ MI _RTCMAC [32] ⊕ MI _RTCMAC [34] ⊕ MI _RTCMAC [41],

where ⊕ denotes the operation “Exclusive or”, and MQ _RTCMAC [i] and MI _RTCMAC [i]

denote i ^{th the} low bits of MQ _RTCMAC and MI _RTCMAC , respectively.

Flexible forward link aggregation mode

Access terminal 106 may utilize a multi-carrier DRC with a forward link flexible combining mode (flexibly combining data received over a plurality of FL carriers). In this mode, the base station 104 does not have to transmit packets on individual forward links at the same time, that is, this option will support flexible transmission on carriers with asynchronous transmissions. Access terminal 106 may indicate a DRC index based on transmission to an access terminal 106 in a given segment on a plurality of FL carriers by the same base station 104.

In one embodiment, the system or network 100 may use the General Attribute Update Protocol (GAUP) to indicate that all packet transmissions to a given terminal 106 will be multi-carrier transmissions over a period of time. Access terminal 106 may, unless otherwise prescribed, transmit a DRC based on joint SINR prediction. The MAC level 1400 (FIG. 14) may provide a signal mapping.

The network may have some flexibility to serve the access terminal 106 using a single carrier or a combination of carriers in the same time interval. It can use single carrier DRCs, as well as DRCs based on joint SINR prediction. The network may configure the access terminal 106 to operate in one of these two DRC message modes. Flexible forward link combining can be used, for example, when the access terminal 106 experiences poor channel conditions for VoIP streams or for all types of streams.

FIG. 13A illustrates an example of a forward link path, structure, or process that may be implemented in the base station 104 of FIG. 1. The functions and components shown in FIG. 13A may be implemented by software, hardware, or a combination of software and hardware. Other functions may be added to FIG. 13A in addition to or instead of the functions shown in FIG. 13A.

At block 1302, the encoder encodes the data bits using one or more coding schemes, providing encoded data chips. Each coding scheme may contain one or more types of coding, such as cyclic redundancy check (CRC), convolutional coding, turbo coding, block coding, other types of coding, or no coding at all. Other coding schemes may include automatic repeat request (ARQ), hybrid ARQ, and incremental redundancy repeat methods. Different types of data can be encoded with different coding schemes.

At block 1304, an interleaver interleaves the coded data bits to counteract fading. At a block 1306, a modulator modulates encoded, interleaved data to generate modulated data. Examples of modulation techniques include bit phase shift keying (BPSK) and quadrature phase shift keying (QPSK).

At block 1308, the repeater may repeat the modulated data sequence, or the symbol puncture element may delete individual bits of the symbol. At block 1310, an expander (e.g., a multiplier) can expand the modulated data by masking Walsh (i.e., a Walsh code) to generate data chips.

At a block 1312, a time division multiplexer may multiplex chip data with chip pilot and MAC chip to form a chip sequence. At a block 1314, a pseudo-random (PN) noise expander can extend the chip sequence with one or more PN codes (eg, short code, long code). Then, the forward link modulated signal (transmitted chips) is transmitted through the antenna over the wireless link to one or more access terminals 106.

FIG. 13B illustrates an example of a path, process, and reception structure of a forward link that may be implemented in the access terminal 106 of FIG. 1. The functions and components shown in FIG. 13B may be implemented by software, hardware, or a combination of software and hardware. Other functions may be added to FIG. 13B in addition to or instead of the functions shown in FIG. 13B.

One or more antennas 1320A-1320B receive modulated forward link signals from one or more base stations 104. Multiple antennas 1320A-1320B can provide spatial diversity to counteract harmful signal paths, such as fading. Each received signal is supplied to a receiver filtering unit 1322 of a corresponding antenna, which converts (e.g., filters, amplifies, downconverts) and digitizes the received signal to generate data samples for that received signal.

The cascade adaptive linear equalizer 1324 receives data samples and generates adjusted chips for block 1325. Block 1325 can compress the samples using one or more PN codes used in block 1314. Block 1326 can remove the temporal errors of the pilot signals and insert spaces. At block 1328, the compression block may perform compression or deletion of Walsh codes from the received data samples using the same extension sequence as that used to expand the data in block 1310 at the base station.

At block 1330, a demodulator demodulates data samples for all received signals to provide recovered symbols. For cdma2000, demodulation attempts to restore data transmission by (1) channelizing compressed samples to isolate or channeling the received data and pilot into their corresponding code channels, and (2) coherent demodulating the channelized data with the reconstructed pilot to provide demodulated data. Demodulation unit 1330 may implement a Rake receiver for processing multiple instances of signals.

Block 1334 may obtain locations of punctured characters and convert characters to consecutive bits. Block 1332 may nullify the likelihood logarithm relationships (LLRs) in punctured bit intervals. Block 1336 may apply reverse channel interleaving.

At block 1338, the channel decoder decodes the demodulated data to recover the decoded data bits transmitted by the base station 104.

The term "information channel" as disclosed herein may refer to a DRC channel, an ACK channel, or other channels containing channel status information.

It is understood that the embodiments described herein provide some embodiments of an asymmetric mode of operation for multi-carrier communication systems. There are other options for implementation and implementation. Various disclosed embodiments may be implemented in AN, AT, and other elements of multi-carrier communication systems.

Specialists in the art should understand that information and signals can be represented using any variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the description above may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination of this.

Those skilled in the art will also 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, software, or combinations of the two. 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 functionality such as hardware or software is implemented depends on the particular application and design constraints imposed on the system as a whole. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implemented solutions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or implemented by a universal processor, a digital signal processor (DSP), a specialized integrated circuit (ASIC), a user programmable logic element array (FPGA), or another programmable logic device, a discrete logic element or transistor logic circuit, discrete hardware components, or any combination of these, is designed Anne, to perform the functions described herein. A universal 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, for example, 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 implemented directly by hardware, a software module executed by a processor, or a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EEPROM memory, register, hard disk, removable disk, CD-ROM or any other form of storage device. A storage device is coupled to the processor so that the processor can read information from and write information to the storage device. In the alternative, the storage device may be an integral part of the processor. The processor and storage device may reside in the ASIC. This ASIC may reside in a user terminal. In the alternative, the processor and the storage device may reside as separate components in a user terminal.

Headings are provided here for reference and to assist in locating specific sections. These headings are not intended to limit the scope of the concepts described there, and these concepts can be applied throughout the other sections of the description.

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 of these embodiments will immediately be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited by the embodiments shown here, but should be within the broadest scope consistent with the disclosed principles and new features.

Claims (31)

1. A method of providing asymmetric modes of operation in a multi-carrier wireless communication system, the method comprising the steps of:
assigning a long code mask (LCM) to an information channel associated with a plurality of forward link carriers for transmitting data from a base station or access network to an access terminal;
informing the access terminal whether to multiplex the information channel based on feedback from the access terminal; and
multiplex the information channel on the carrier of the reverse link. 2. The method of claim 1, wherein the information channel comprises at least one of data source channel information (DSC), data rate control (DRC) information, and acknowledgment information (ACK). 3. The method according to claim 2, in which the ACK information in the reverse link is further biased to reduce the peak value of the reverse link to an average value. 4. The method of claim 2, further comprising informing the access terminal whether to multiplex DSC information based on feedback from the access terminal. 5. The method according to claim 1, in which the multiplexing is code multiplexing (CDM). 6. The method according to claim 5, in which additionally multiplexed with code division of the information channel in the I-branch and in the Q-branch. 7. The method according to claim 5, in which the information channel contains information control data transfer rate (DRC), both in the I-branch and in the Q-branch. 8. The method according to claim 5, in which the information channel contains acknowledgment information (ASK), both in the I-branch and in the Q-branch. 9. The method of claim 5, further comprising transmitting an information channel code-multiplexed on a reverse link carrier. 10. The method of claim 7, further comprising masking the data rate control (DRC) information with Walsh codewords. 11. The method of claim 8, further comprising masking the acknowledgment information (ASK) with Walsh codewords. 12. The method according to claim 7, further comprising combining data rate control (DRC) information with data rate control masking symbols in both the I-branch and the Q-branch. 13. The method of claim 12, wherein the data rate control (DRC) closing symbols are channelized by offset Walsh codes. 14. A system for providing asymmetric modes of operation in a multi-carrier wireless communication system, comprising:
a controller configured to:
assigning a long code mask (LCM) to an information channel associated with a plurality of direct forward link carriers for transmitting data from a base station or access network to an access terminal, the access network being configured to tell the access terminal whether the information channel should be multiplexed based on feedback from the access terminal; and
an access terminal configured to multiplex an information channel on a reverse link carrier. 15. The system of claim 14, wherein the controller is located in the base station. 16. The system of claim 14, wherein the controller is located in the controller of the base station or access network. 17. The system of claim 14, wherein the information channel comprises at least one of data source channel information (DSC), data rate control information (DRC), and acknowledgment information (ASK). 18. The system of claim 17, wherein the access terminal is configured to bias the ACK information in the reverse link to reduce the peak value of the reverse link to an average value. 19. The system of claim 14, wherein the multiplexer is a code multiplexer (CDM). 20. The system of claim 19, wherein the access terminal is configured to transmit an information channel code-multiplexed on a reverse link carrier. 21. The system of claim 17, wherein the access network is configured to tell the access terminal whether to multiplex DSC information based on feedback from the access terminal. 22. An access terminal comprising:
a receiver for receiving data from a base station in a long code mask (LCM) of an information channel associated with a plurality of forward link carriers;
a transmitter for transmitting data on a reverse link carrier to a base station; and
means for multiplexing the information channel on the reverse link carrier, wherein the means for multiplexing is configured to multiplex the information channel if the access network informs the access terminal that the information channel should be multiplexed based on feedback from the access terminal. 23. The access terminal of claim 22, wherein the multiplexing means comprises code division multiplexing (CDM) means. 24. The access terminal of claim 22, further comprising means for code division multiplexing the information channel in the I-branch and Q-branch. 25. The access terminal according to paragraph 24, in which the information channel contains information control data transfer rate (DRC), both in the I-branch, and in the Q-branch. 26. The access terminal according to paragraph 24, in which the information channel contains acknowledgment information (ACK), both in the I-branch and in the Q-branch. 27. The access terminal of claim 22, further comprising means for transmitting a code division multiplexed information channel on a reverse link carrier. 28. The access terminal of claim 25, further comprising means for masking data rate control (DRC) information with Walsh codewords. 29. The access terminal of claim 26, further comprising means for masking acknowledgment information (ACK) with Walsh codewords. 30. The access terminal of claim 25, further comprising means for combining data rate control (DRC) information with data rate control (DRC) masking symbols in both the I-branch and the Q-branch. 31. The access terminal of claim 31, wherein the data rate control (DRC) masking symbols are channelized by offset Walsh codes.

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