Feedback of channel state information for mimo and subband scheduling in a wireless communication system

Technical Field The present invention relates generally to communication, and more specifically to techniques for sending channel state information.

II. Background Art [0002] In a wireless communication system, the base station may use multiple (T) transmission antennas to transmit data to a terminal equipped with multiple (R) receive antennas. The set of transmission and receiving antennas forms a multi-input-multi-output (MIMO) channel, which channel can be used to increase throughput and / or improve reliability. For example, to increase throughput, the base station may simultaneously send up to T data streams from T transmission antennas simultaneously. Alternatively, the base station may send one data stream from all T transmission antennas to improve reception at the terminal.

[0003] Good performance can be achieved by transmitting one or more data streams over the MIMO channel in such a way that the highest total throughput can be achieved for data transmission. To facilitate this, the terminal can estimate the MIMO channel response and send the channel status information to the base station. Channel status information may indicate how many data streams to send, how to send data streams, and provide a channel quality indicator (CQI) for each data stream. The CQI for each data stream can indicate the received signal to noise ratio (SNR) for the data stream and can be used to select the appropriate data stream speed. Channel status information can improve the performance of data transmission to the terminal. However, the terminal may consume a large amount of radio resources to send channel status information to the base station.

[0004] Therefore, there is a need in the art for techniques to efficiently send channel state information in a wireless communication system.

[0005] In the document "AMC and HARQ using freedom domain domain-dependent scheduling in MIMO channel transmission", draft 3GPP of August 25, 2005, a reduction of CQI bits in MIMO multiplexing is disclosed in which CQI bits are generated among antennas and differential CQI bits are reported to the base station in the area of ​​space in the uplink control channel.

Summary [0006] The present invention relates to a device, method and computer medium as defined in the appended claims.

Brief Description of the Drawings [0007] Fig. 1 is a schematic diagram of a base station and terminal.

[0008] Fig. 2 shows CGI values ​​for M spatial channels in N subbands.

[0009] Fig. 3A shows CQI differential coding in the space domain.

[0010] Fig. 3B shows the CQI differential coding in the frequency domain ..

[0011] Fig. 3C shows CQI differential coding in space and frequency domain.

[0012] Fig. 3D shows CQI differential coding in the domain of space, frequency and time. [0013] Fig. 4A shows CQI differential coding in the subband space domain.

[0014] Fig. 4B shows CQI differential coding in space and frequency domain. [0015] Fig. 4C shows CQI differential coding in space, frequency and time domain. [0016] Fig. 5 illustrates heterogeneous CQI reporting.

[0017] Fig. 6 and Fig. 7 respectively show the process and the device for reporting channel status information by differential coding in space and frequency domain.

[0018] Fig. 8 and Fig. 9 respectively show the process and the device for reporting channel status information by differential coding in the domain of space, frequency and time.

[0019] Fig. 10 and Fig. 11 show a process and device for heterogeneously reporting channel state information, respectively.

Detailed Description [0020] The techniques for sending channel state information described herein can be used for various communication systems that support MIMO transmission and use any form of frequency division multiplexing (FDM). For example, these techniques can be used for systems that use orthogonal frequency division multiplexing (OFDM), single carrier frequency multiplexing (SC-FDM), etc. OFDM and SC-FDM divide the system band into many (K) orthogonal subcarriers, which are also referred to as tones, bins, etc. Each subcarrier can be modulated by data. In general, modulation symbols are sent in the frequency domain at OFDM and in the time domain at SC-FDM.

[0021] These techniques can also be used to send channel state information on the downlink or on the uplink. The downlink or forward link refers to the communication link from the base station to the terminal, and the uplink or reverse link refers to the communication link from the terminal to the base station. For clarity, techniques for sending uplink channel status information are described below.

[0022] Fig. 1 is a schematic diagram of the design of base station 110 and terminal 150 in a wireless communication system 100. Base station 110 may also be referred to as: Node B, expanded NodeB (eNode B), access point, etc. Terminal 150 may also be referred to as user equipment (UE), mobile station, access terminal, subscriber unit, station, etc. Terminal 150 can be a cell phone, PDA, wireless communication device, handheld device, wireless modem, laptop computer, etc. Base station 110 is equipped with many (T) antennas from 134a to 134t. Terminal 150 is equipped with many (R) antennas from 152a to 152r. Each transmission antenna and each receiving antenna may be a physical antenna or an antenna array.

[0023] At base station 110, the broadcast data processor (TX) 120 may receive traffic data from data source 112, process (e.g., format, coding, interleaving, and symbol map) traffic data according to package format, and generate data symbols. As used herein, the term data symbol means a symbol for data, the term pilot symbol means a symbol for pilot, and the symbol is usually π

"J is a complex value. Data symbols and pilot symbols may be modulation symbols from the PSK or QAM modulation scheme. The remote control is data that is known in advance by the base station and terminal. The packet format may indicate the data transmission rate, coding scheme or code efficiency, modulation scheme, packet size, and / or other parameter. The term packet format can also refer to a modulation and coding scheme, indicator, etc. TX 120 data processor may demultiplex data symbols in M ​​streams, where generally 1 <Μ <Τ. M data symbol streams can be sent through the MIMO channel simultaneously, and they can also be referred to as data streams, spatial streams, traffic streams, etc.

[0024] The TX MIMO processor 130 can perform spatial processing in the transmitter on data symbols and pilot symbols based on direct MIMO mapping, precoding, etc. The data symbol can be sent from one antenna in the case of direct MIMO mapping or from multiple antennas in the case of precoding. Processor 130 may provide T streams with output symbols to T modulators (MOD) 132a through 132t. Each modulator 132 can perform modulation (e.g. for OFDM, SC-FDM, etc.) of the output symbols so as to obtain output chips.

Each modulator 132 further processes (e.g., converts to analog, filters, amplifies, and converts upconverts) its output chips and generates a downlink signal. T downlink signals from modulators 132a through 132t are transmitted via antennas 134a through 134t, respectively.

[0025] At terminal 150, R antennas 152a to 152r receive T downlink signals, and each antenna 152 provides the received signal to the appropriate demodulator (DEMOD) 154. Each demodulator 154 processes (e.g., filters, amplifies, converts down) (downconverts), and digitizes) the signal received by it to obtain samples and be able to further demodulate (e.g. for OFDM, SC-FDM, etc.) samples to obtain the received symbols. Each demodulator 154 may provide the received data symbols to the MIMO receiving processor (RX) 160 and may provide the received pilot symbols to the channel processor 194. The channel processor 194 may estimate the MIMO channel response from base station 110 to terminal 150 based on the received pilot symbols and provide values estimated channel to the RX MIMO 160 processor. The RX MIMO 160 processor can perform MIMO detection on received data symbols using channel estimates and provide data symbol estimates. The RX 170 data processor can process (e.g., deinterlace and decode) estimates of the data symbol and provide / decoded data to data outlet 172.

[0026] Terminal 150 may evaluate channel conditions and send channel state information to base station 110. Channel state information may be processed (e.g., coded, interlaced, and mapped to a symbol) by TX 180 signal processor, processed in the field space by the TX MIMO 182 processor, and then processed by modulators 154a to 154r in order to generate R uplink signals that are transmitted through antennas 152a to 152r.

At base station 110, R uplink signals are received through antennas 134a to 134t, processed through demodulators 132a through 1321, processed in the space domain by an RX MIMO 136 processor, and then processed (e.g. deinterlacing and decoding) by the RX signal processor 138 so as to recover channel status information sent by terminal 150.

The controller / processor 140 may control the transmission of data to the terminal 150 based on channel status information received from the terminal.

[0028] Controllers / processors 140 and 190 control operation at base station 110 and terminal 150, respectively. Memories 142 and 192 store data and program codes for base station 110 and terminal 150, respectively. Planner 144 may select terminal 150 and / or other terminals in downlink data transmission based on channel status information received from all terminals.

[0029] For downlink transmission from base station 110 to terminal 150, S spatial channels may be available, where 5 <min {r, R}. S spatial channels can be created in various ways. In the case of direct MIMO mapping, S data streams can be sent from S transmission antennas, with one data stream per transmission antenna. S spatial channels may therefore correspond to S transmission antennas used for data transmission. In the case of precoding, S data streams can be multiplied by a precoding matrix so that each data stream can be sent from all T transmission antennas. S spatial channels may therefore correspond to S "virtual" antennas seen through S data streams and created using a precoding matrix. Generally, M data streams can be sent in M ​​spatial channels, with one data stream per spatial channel, where 1 <M <S. M spatial channels can be selected from S available spatial channels based on one or more criteria, such as total capacity.

[0030] For simplicity, the following description assumes that each data stream is sent in one spatial channel that may correspond to a real antenna or virtual antenna, depending on whether direct MIMO mapping or precoding has been used. The terms "data streams", "spatial channels", and "antennas" can be used interchangeably. M packets or code words can be sent simultaneously in M ​​data streams.

[0031] Terminal 150 can recover M data streams using various MIMO detection techniques such as linear minimum mean square error (MMSE), zero-forcing (ZF), successive interference cancellation (SIC) ), etc., all of which are known in the art. SIC involves recovering one data stream at a time, estimating interference caused by each recovered data stream, and reducing interference before recovering the next data stream. SIC can improve the received SNRs of data streams that are recovered later.

[0032] System 100 may support subband planning to increase performance. The system bandwidth can be divided into many (N) subbands. Each subband can cover Q consecutive subcarriers among K all subcarriers, where G = K / N or some other value. Terminal 150 can achieve different SNRs for different subbands due to selective frequency fading in the multi-path channel. Using subband planning, terminal 150 may be allocated subcarriers in a subband with good SNR instead of in a subband with weak SNR. Data can be sent at a higher rate on carriers allocated in the subband with a good SNR, [0033] Terminal 150 may send channel state information to support subband planning and MIMO transmission from base station 110. Channel state information may include:

• spatial state information for MIMO transmission, and • CQI information, used for subband planning, rate selection, etc.

[0034] The spatial state information may contain various types of information. In one design, the spatial state information for a given subband may indicate a set of M transmission antennas that can be used to transmit data in this subband. Terminal 150 can estimate the MIMO channel response, evaluate the various possible sets of transmission antennas based on the MIMO channel estimation, and determine the set of transmission antennas with the best performance (e.g., with the highest total throughput). Therefore, spatial state information may point to this set of transmission antennas.

[0035] In another design, the spatial state information for a given subband may indicate a set of M virtual antennas (or equivalent set of M precoding vectors) that can be used for transmission in that subband. Terminal 150 may evaluate data performance with different precoding matrixes and / or with different combinations of precoding matrix columns. The spatial state information may therefore indicate a set of M best-coding vectors, e.g., a particular precoding matrix as well as M specific columns of this precoding matrix.

[0036] In general, the spatial state information may indicate the number of data streams to be transmitted (which may be related to the MIMO channel order number), a set of antennas to be used for transmission, a set of pre-coding vectors to be used for transmission , other information, or any combination thereof. Spatial state information may be provided for one or more subbands.

[0037] CQI information may carry SNRs or equivalent information for different spatial channels and / or different subbands. Due to the frequency selectivity of the wireless channel for different subbands, different SNRs may be achieved. Different SNRs can also be achieved for different spatial channels if base station 110 uses direct MIMO mapping for data transmission, if terminal 150 performs successive interference reduction when receiving data, etc. Thus, for different spatial channels on different subbands, different SNRs can be achieved. The SNR value of a given spatial channel in a given subband can be used to select the appropriate packet format, which may indicate code efficiency, modulation scheme, data transmission rate, etc., to be used to send data through this spatial channel in that subband. In general, CQI information may carry SNRs and / or other information indicating the quality of the received signal for one or more spatial channels and / or one or more subbands.

[0038] Fig. 2 shows CQI values ​​for M spatial channels on N subbands. CQI X value_iiiu can be obtained for each spatial channel m in each subband n. Number of values

CQI can therefore be proportional to the product of the number of spatial channels and the number of subbands, or CQI values ​​can be Μ · N. These CQI values ​​can be used to plan a subband to select the appropriate subband for data transmission. These CQI values ​​can also be used to determine the appropriate packet format for each spatial channel in each subband. However, sending all Μ N CQI values ​​to the base station can consume a significant amount of uplink resources.

[0039] Differential encoding can be used to reduce the amount of channel state information sent. Differential coding refers to reporting differences between values ​​instead of actual values. If the change in values ​​is small compared to the current values, then the differences can be reported using fewer bits than the current values. Differential coding can provide good performance by reducing signaling overhead. Differential coding can be performed on CQI values ​​in the space domain, in the frequency domain, in the space and frequency domain, in the space, frequency and time domain or in some other combination of dimensions.

[0040] Table 1 presents a list of various information that can be sent for CQI information. The full CQI value can also be referred to as: CQI value, axial CQI value, current CQI value, etc. The differential CQI value can report the difference between two full CQi values ​​(e.g., Y or, \ X) or the difference between two differential CQI values ​​(e.g., ΥΥ, Λ / ΥΥ, ΛΔΥ). In general, differential CQI information may include any information indicating differences between full and / or differential CQI values, e.g., Y, ζΥΥ, ΔΥ, ΔΛ.Υ and / or ΛΛΥ in Table 1.

<td>Symbol</td><td>Description</td>

<td>X</td><td>The full CQI value (e.g., SNR value) for the spatial channel in the subband.</td>

<td>Y</td><td>The difference between CQI values ​​for two spatial channels in the same subband.</td>

<td>ΛΥ</td><td>The difference between CQI values ​​for a given spatial channel in two sub-bands.</td>

<td>ΛΥ</td><td>The difference between the Y values ​​for the two subbands.</td>

<td>ΔΔΥ</td><td>The difference between ΔΧ values ​​for two time intervals.</td>

<td>ΔΔΚ</td><td>The difference between ΔΥ values ​​for two time intervals.</td>

Table 1 [0041] For differential coding in the spatial domain, one spatial channel may be a designated spatial channel and the other spatial channels may be non-designated spatial channels. A full CQI value may be provided for a designated spatial channel, and a differential CQI value may be provided for each non-designated spatial channel or for all non-designated spatial channels. For frequency coding, one subband may be a designated subband and the other subbands may be non-designated subbands. A full CQI value may be provided for the designated subband, and a differential CQI value may be provided for each non-designated subband. For time-domain differential coding, one time period may be a designated time period, and one or more other time intervals may be non-designated time intervals. A full CQI value can be provided for a designated time period, and a differential CQI value can be provided for each unspecified time interval. The designated subband can also be referred to as: basic subband, preferred subband, reference subband,

-Ί etc. The designated spatial kanat and the designated time interval may also be defined by other terms.

[0042] Fig. 3A shows a CQI space coding design for two spatial channels in one subband. In this example, the CQI value is X _t is obtained for the designated spatial channel a and the CQI value is X_h is obtained for a non-designated spatial channel. Terminal 150 (or transmitter) can obtain and send the following CQI information:

X = X ,, i '(1)

ΧΥ-γ.

[0043] Base station 110 (or receiver) may receive X and Y from terminal 150 and may obtain the original CQI values ​​as follows:

Λ = X, iw

X_h = X + Y.

[0044] The CQI values ​​obtained by the base station 110 may not be exactly the same as the CQI values ​​obtained by the terminal 150 due to the X and Y quantization. For simplicity, much of the description herein assumes no quantization error.

[0045] Fig. 3B illustrates a frequency domain CQI coding design for one spatial channel on two subbands. In this example, the CQI value is X_t is obtained for a spatial channel in designated subband 1, any CQI value equal to AJ is obtained for the same spatial channel in non-designated subband 2. Terminal 150 can obtain and send the following CQI information:

X = X ,, and δχ = χ₂-χ ,. ⁽³⁾ [0046] Base station 110 may receive X and ΧΧ from terminal 150 and may obtain the original CQI values ​​as follows:

X, = X. 'i (4)

AJ = X + t \ X. '' [0047] CQI differential coding in the frequency domain can be used if a single data stream is sent on a single spatial channel. In this case, a differential CQI value for another spatial channel may not be needed.

[0048] Fig. 3C shows a CQI differential coding design in space and frequency domain for two spatial channels on two subbands. In this example, the CQI value equal to A 'is obtained for the designated spatial channel a and the value of CQI equal X_ih is obtained

-8 for an undetermined spatial channel b in designated subband 1. A CQI value of ΛΤ, and .Y_v are obtained for spatial channels a and b, respectively, in non-designated subband 2. Terminal 150 may obtain the following CQI information.

<img file="PL1999876T3_D0001.tif" />

r, (5) where and Y₂ are the differential CQI values ​​for the spatial channel b in subbands 1 and 2, respectively. Terminal 150 may send X and Y as CQI information for subband 1 and may send ΑΑ 'ίΔΚ as CQI information for subband 2.

[0049] Base station 110 may receive X, Y, Δ.Α ίΔΓ from terminal 150 and may output the original CQI values ​​as follows:

y = x + Y

X_2a= X + AX, and X_2h = X + AX ​​+ Y + AY.

(6) [0050] In the design shown in equation (5), differential coding is performed first in the space domain and then in the frequency domain. Differential coding can also be performed first in the frequency domain and then in the space domain.

[0051] Fig. 3D shows a design of differential CUT coding in the domain of space, frequency and time for two spatial channels on two subbands at two time intervals. During time interval 1, CQI values ​​equal to X_la and Χ_ίΛ are obtained for spatial channels a and b in designated subband 1 and the values ​​of CQI X_2u and X_at are obtained for spatial channels a and b in non-designated subband 2. In time interval 2, CQI values ​​equal to X_la and X_i2 are obtained for spatial channels a and b in subband 1 and CQI X values_2iland A%, are obtained for spatial channels a and b in subband 2. Terminal 150 may obtain CQI information for time interval 1 as shown by the set of equations (5).

[0052] Terminal 150 may obtain CGI information for time interval 2 as follows:

Λ * = Λ, - Α ', ".

Δ} ·· =) ί -}; = (Ύ_1Λ-χ₁₍) - (. Ν,_Λ-χ_{Ι (},).

-ν- '-νΙΪ Ί

ΔΔΧ = ΔΆ^Ζ2 - XX = (Χ "-Χ,") - (Α, -Λ -, ") - / νν,

ΔΔ / = Δ Υ \ - Δ Υ = (/ - ή) - (/ - Υ,)

ΛΕ Λ&gt; '(7) (Ύ_2Λ - Χ '₂) - (Ύ_Ιή - Ύ, ") - (Χ_2Λ - Χ₂) + (Ύ_ιλ - Λ,) where Δλ^Λ is the difference between the CQI values ​​for the spatial channel in subband 1 in two time intervals, Δ / is the difference between the values ​​of Y for the spatial channel b in subband 1 in two time intervals, ΑΑΧ is the difference between the values ​​of ΔΥ for the spatial channel in two time intervals, and ΔΔΓ is the difference between the ΔΓ values ​​for the spatial channel b in two time intervals.

[0053] For time interval 1, terminal 150 may send X and Y as CQI information for subband 1 and may send XX and Δί⁷ as CQI information for subband 2. For time interval 2, terminal

150 can send XX and Δ}⁷ as CQI information for subband 1 and may send ΔΔΧ and ΔΔ / as CQI information for subband 2.

[0054] Base station 110 may receive from terminal 150 the X, Y, ΥΥ and Δ / values ​​in time interval 1 and may receive XX, Δ /, ΔΔΛ values⁷ and ΔΔ / in time interval 2. Base station 110 can obtain the original CQI values ​​for time interval 1 as shown by the set of equations (6). Base station 110 can output the original CQI values ​​for time interval 2 as follows:

x \_and = x + ax \

X "= X '_{a +} Y ₊ AY ₍₈₎

X '_2u = x '_and + XX + ΔΛΧ, i

X₂"= X '_lh+ AX + AAX + AY + AAY = X_2a+ Y + AY + ΔΥ + ΔΑΥ.

[0055] In the design shown in equation (7), differential coding is performed first in the space domain, then in the frequency domain, and finally in the time domain. Differential coding can also be performed first in the frequency domain, then in the space domain, and finally in the time domain.

[0056] For simplicity, Figs. 3A-D show differential coding for two spatial channels, two subbands, and two time intervals. Differential coding can be extended to any number of spatial channels, any number of subbands, and any number of time intervals.

[0057] Differential coding in space for more than two spatial channels can be performed in various ways. One project assumes that CQI values ​​for spatial channels are related by a linear relationship by a common value of Y. Thus, if

- the designated spatial channel has a CQI value of X, then the spatial channel b has a CQI value of X = Y, the spatial channel c has a CQI value of Χ + 2Υ, the spatial channel d has a CQI value of Χ + 3Υ etc. A single Y value can be sent for all non-designated spatial channels. In another design, a separate Y value may be calculated for each non-designated spatial channel relative to a designated spatial channel or an adjacent spatial channel. For example, if the spatial channels a, b, c and d have CQi values ​​of X, respectively_tl, X_h, X_c and X_d , then the Y values ​​for the b, c and d spatial channels can be calculated as Y, respectively_h - X_h - X_at, Y_c = X_c -X_h, and Y_t! = X_d -X_c. For the spatial channels b, c and d, the Y values ​​can be sent respectively_h, Y_c. and Y_d. \ N yet another project, a separate Y value can be calculated for each non-designated spatial channel. A single index can then be sent to provide Y values ​​for all non-designated spatial channels. Different combinations of Y values ​​can be defined and stored in a look-up table. A single index may indicate a particular combination of Y values ​​in the preview table that is closest to the set of calculated Y values. Y values ​​for many non-designated spatial channels may also be transmitted in a different way. For simplicity, much of the following description assumes that there is one non-designated spatial channel.

[0058] In general, any number of bits can be used for each piece of information contained in the channel state information. The following notation is used in the following description:

N_v - number of bits for the full CQI X value,

N_r - number of bits for the differential CQI Y value,

N_at. - number of bits for both differential CQI AX and NY values,

Ny - number of bits for spatial state information, and

N_x - the number of bits indicating the designated subband, which is Λ \. = [log, Nj.

[0059] The number of bits used for a given piece of information may be selected based on a trade-off between the amount of detail or resolution for the information and the signaling overhead. In one example of a project, jV_v= 5, ŁV_r= 3, N_IN= A, AL, = 2 for a 2-layer MIMO with M = 2, and N_s = 4 for a 4-layer MIMO with M = 4. For N_x , N_Y, N_iv and Ν_χ other values ​​may also be used.

[0060] A variety of reporting schemes can be used to send channel status information in an efficient manner. Some reporting schemes are described below.

[0061] Fig. 4A shows a first reporting scheme using CQI differential coding in space domain and independent coding for each of the N subbands. In this scheme, the full CQI value X_n, differential CQI Y value_n, and spatial state information may be sent to each of the N subbands. The CQI report for all N subbands may contain N - (Ny + Ny + Ny) bits. Full CQI X value_n and differential CQI Y value_n for each subband n can be determined as shown by the set of equations (1).

[0062] The second reporting scheme uses differential CQI coding in the space domain and independent coding for a subset of N subbands. This subset can contain L subbands and can be identified by the N, -bit subband index, where L&gt; 1 and N,&gt; 1. For example, if there are eight subbands and up to three consecutive subbands can be reported, then V_; can be equal to 5. In this scheme, the full CQI X value_n, differential CQI Y value_n, and spatial state information may be sent for each of the L subbands. The CQI report for L subbands may contain L · (jV_from + yV +? Vj) + X_t bits.

[0063] CQI information may also be sent to different subsets of subbands at different time intervals. For example, N subbands can be switched, and CQI information for one subband can be sent using N_x + N_Y + N_s bits in each time interval. CQI information for more than one subband may also be sent at any time interval.

[0064] The third reporting scheme uses CQI differential coding in the space domain, independent coding for N subbands, and common spatial state information for all N subbands. For each subband, a set of spatial channels (e.g., set of antennas or pre-coding vectors) can be determined that provides the best performance (e.g., highest total bandwidth) for this subband. The best spatial channel set out of the N spatial channel sets can be selected for N subbands and used as a common set of spatial channels for all N spatial channels. Alternatively, the spatial channel set that provides the best average bandwidth for all N subbands can be selected as a common set of spatial channels. Full and differential CQI values ​​can be obtained based on a common set of spatial channels. The CQI report for all N subbands may contain N_x + N- (N_Y + X_r) bits. Common spatial state information may also contain other information instead of a common set of spatial channels or together with a common set of spatial channels. In another design, spatial state information may be reported to a specific unit (e.g., each subband), and CQI information may be averaged and reported to a larger entity (e.g., a set of spatial state reporting units). The CQI reporting unit may therefore be larger than the spatial state reporting unit, e.g. in the frequency domain.

[0065] Fig. 4B shows a fourth reporting scheme that uses differential CQI coding in spatial and frequency dimensions. In this scheme, the full CQI value, the differential CQI value Γ, and spatial state information can be provided for the designated subband and can be sent using N_from + (; V_v + / V ,.) bits. The designated subband may be a predetermined subband (e.g. subband 1), the best performance subband, etc. If the designated subband is not fixed, then X_s bits may be sent to indicate which subband is the designated subband. Differential CQI XX and ΔΓ values ​​can be obtained for

- 12 each non-designated subband based on common spatial state information (e.g., a common set of spatial channels) and sent to. this subband. The CQI report for all N subbands may contain; V_FROM + (/ V_v + N_Y) + (; V -1) · N_IY + bits.

[0066] In one design, CQI differential frequency coding is achieved by taking the difference between adjacent subbands. In this design, differential CQI information for non-designated subband n may include differential CQI AX values_lt = X_n - X_ll__l and AY_n= Y_n -lA between subbands n and n-1 or differential AX values_n = X_n - X_{and ii +} and AY "= Y_n -Y_{n + I} between subbands n and n + 1.

[0067] The CQI report may contain different pieces of information in different formats. The N subbands indexes can be organized in a monophonic manner so that subband 1 occupies the lowest frequency range and subband N occupies the highest frequency range in the band system, as shown in Fig. 2. If subband f is the designated subband, then the first jV_s. bits can pass the index of the designated subband f, followed by N₇ bits can transmit spatial state information for subband f, followed by N_x + N_Y bits can pass the full CQI X value_t and differential CQI Y value_e for subband t. Next N_ir bits can transmit differential CQi information (e.g., AX_{f +]} and AK_{f + and}) between the subbands {and (+1 in spatial and frequency dimensions. Next N_IY bits can transmit differential CQI information between f + 1 and f + 2, and so on, and N_fy bits may convey differential CQI information between subbands N-1 and N. Then the next N,_r bits can transmit differential CQI information between fi f-1 subbands, followed by N_IY. bits can transmit differential CQI information between subbands f-1 and 1-2, and so on, and the last N_in bits can transmit differential CQI information between subbands 2 and 1.

[0068] The first three columns of Table 2 show the design of differential CQI information for differential coding between adjacent subbands. In this design, differential CQI information for each non-designated subband n contains N_IV = 4 bits and in total provides (i) the differential CQI AX value_n between the subband and the adjacent subband for the designated spatial channel, and (ii) the differential CGI AY value_n for an unspecified spatial channel. The CQI value for each spatial channel in each subband may be determined as shown by the sets of equations (5) and (6).

<td>differentiation</td><td>between</td><td>neighboring</td><td>differentiation</td><td>terms of</td><td>designated</td>

<td>subbands</td><td></td><td></td><td>subbands £</td><td></td><td></td>

<td>Index</td><td>Λ-Υ ,.</td><td>Δξ.</td><td>Index</td><td>ΔΧ ,.</td><td>Δξ</td>

<td> 0</td><td> 0</td><td> -2</td><td> 0</td><td> -3</td><td> -2</td>

<td> 1</td><td> -2</td><td> -1</td><td> 1</td><td> -2</td><td> -2</td>

<td> 2</td><td> -1</td><td> -1</td><td> 2</td><td> -1</td><td> -2</td>

<td> 3</td><td> 0</td><td> -1</td><td> 3</td><td> 0</td><td> -2</td>

<td> 4</td><td> +1</td><td> -1</td><td> 4</td><td> +1</td><td> -2</td>

<td> 5</td><td> +2</td><td> -1</td><td> 5</td><td> -3</td><td> -1</td>

<td> 6</td><td> -2</td><td> 0</td><td> 6</td><td> -2</td><td> -1</td>

<td> 7</td><td> -1</td><td> 0</td><td> 7</td><td> -1</td><td> -1</td>

<td> 8</td><td> 0</td><td> 0</td><td> 8</td><td> 0</td><td> -1</td>

<td> 9</td><td> +1</td><td> 0</td><td> 9</td><td> -3</td><td> 0</td>

<td> 10</td><td> +2</td><td> 0</td><td> 10</td><td> -2</td><td> 0</td>

<td> 11</td><td> -2</td><td> +1</td><td> 11</td><td> -1</td><td> 0</td>

<td> 12</td><td> -1</td><td> +1</td><td> 12</td><td> 0</td><td> 0</td>

<td> 13</td><td> 0</td><td> +1</td><td> 13</td><td> -3</td><td> +1</td>

<td> 14</td><td> +1</td><td> +1</td><td> 14</td><td> -2</td><td> +1</td>

<td> 15</td><td> +2</td><td> +1</td><td> 15</td><td> -1</td><td> +1</td>

Table 2 [0069] In another design, CQI differential frequency coding is achieved by taking differences with respect to the designated subband. In this design, differential CQI information for an undetermined subband n may contain differential CQI values ​​ΔΧ_η = X_n -X, and XY_n = Y_n -); between designated subband {and non-designated subband n.

[0070] If the subband £ is the designated subband, then the first N_s bits can pass the index of the designated subband f, followed by Ν_χ bits may transmit spatial state information for subband £ and the following Ν_γ + N_Y bits can pass the full CQI X value_t and differential Y value_t for subband f. Next N_in bits can transmit differential information about CQI (e.g. ΔΧ,_{+ Ϊ} and Δίγ) between the subbands £ and £ + 1 in the space and frequency domain. Next N_in bits can transmit differential CQI information between subbands £ and 1 + 2, and so on, and the next N_{lf /} bits can transmit differential CQI information between subbands £ and N. Then the next; V₍₍. bits can pass differential CQI information between subbands £ and £ -1, followed by N_ie, bits may transmit differential CQI information between subbands £ and -2, and so on and last; V₍₍. the bits may convey differential CQI information between the subbands £ and

1.

[0071] The last three columns of Table 2 show a design of differential CQI information for differential coding with respect to a designated subband. In this design, differential CQI information for each non-designated subband n contains N_tl- = 4 bits and in total provides (i) differential CQI and \ X values_it between subbands € in for the designated spatial channel and (ii) the differential CQI value 11 'for the non-designated spatial channel. If the designated subband has the best performance and is used as a reference for non-designated subbands, then the differential CQI ΔΧ_η for each non-designated subband should be a non-positive value

The CQI value for each spatial channel in each subband may be determined as shown by the sets of equations (5) and (6).

[0072] Table 3 shows another design of differential CQI information for differential coding with respect to the designated subband for N_y = 3 bits.

<td>Index</td><td></td><td>Δξ,</td>

<td> 0</td><td> -2</td><td> -1</td>

<td> 1</td><td> -1</td><td> -1</td>

<td> 2</td><td> 0</td><td> -1</td>

<td> 3</td><td> -2</td><td> 0</td>

<td> 4</td><td> -1</td><td> 0</td>

<td> 5</td><td> 0</td><td> 0</td>

<td> 6</td><td> -2</td><td> + 1</td>

<td> 7</td><td> -1</td><td> + 1</td>

Table 3 [0073] Tables 1 to 3 show some examples of combined coding for differential CQI AAJi ΔΥ values_η. Other joint coding designs can also be used.

[0074] The CQI report may transmit CQI information for all N subbands, e.g. as shown in Fig. 4B. The CQI report may also provide CQI information for a subset of N subbands. In one design, the CQI report for equal time intervals may contain the full CQI X value_t , differential CQI Ę value, and spatial state information for the designated subband £ and can be sent using N_s + N_from + (TV_v + N_Y) bits. The CQI report for the odd time period may contain differential CQI values ​​ΧΧ and ΚΚ for each non-designated subband and can be sent using (N -1) · N_in bits. If there are many subbands, then information about

CQI for non-designated subbands can be sent in multiple time intervals. CQI information for designated and non-designated subbands can also be sent in other ways.

[0075] Fig. 4C shows a fifth reporting scheme that uses CQI differential coding in spatial, frequency and time dimensions. Differential coding can be done in the time domain (e.g. in subsequent reporting intervals) if the wireless channel changes slowly. In this scheme, a CQI report containing spatial-frequency information about CQI may

- 15 be sent every P time periods, where P&gt; 1. The spatial-frequency CQI information may include CQI information generated for one or more spatial channels on one or more subbands based on any of the above described schemes. For example, spatial-frequency CQI information may include + (; V_v + N_s) + (/ V -1) · Aj ,. + Λ \ bits for CQI information generated for two spatial channels in N subbands based on the fourth scheme described above. Spatial-frequency information about CQi may be sent in one time interval or in as many time intervals as possible, as discussed above. One or more CQI reports containing temporal differential CQI information may be sent at intervals between reports with spatial-frequency CQI information. Temporary differential CQI information in each CQI report can be generated relative to the CQI information for the previous CQI report. The time differential CQI information may contain ΛΧ and ΔΥ for a designated subband and ΔΔΥ ί ΔΔΓ for each non-designated subband subject to reporting. The values ​​of ΔΥ, &amp; .Y, ΔΔΥ and ΔΔΓ can be obtained as described above in Fig. 3D. Change of the designated subband can be done every P time intervals. [0076] The first to fifth reporting schemes described above assume that multiple spatial channels are available. If a single spatial channel is used, differential coding may be performed in the frequency domain and the differential CQI Y value may be omitted. The ΔΧ values ​​can be sent using fewer bits because only the difference in the frequency domain (and not in the space domain) is transmitted. Differential coding can also be done in the frequency and time domain. The values ​​XX and Λ / Υ-Ϊ can be sent using fewer bits if differential encoding in the space domain is not performed. [0077] In general, CQI information and spatial state information may be reported at the same rate or at different rates. Spatial state information may be reported at one rate and CQI information may be reported at a second rate, which may be slower or faster than the first speed.

[0078] Channel status information may be generated and reported based on a configuration that may be selected for terminal 150 and may be changed in a semi-static manner by means of signaling. In one design, channel state information can be obtained for a designated subband and reported. In another design, channel state information may be averaged over all subbands (e.g. based on the channel bandwidth function), and information about the average channel state can be reported. If the average channel status information is reported, differential CQI information may be obtained with reference to the average CQI information. In addition, there is no need to transfer the designated subband.

[0079] Spatial state information may depend on the preferences of the terminal 150. In one design, the criterion used to select the set of spatial channels (or set of antennas) may be based on the average channel characteristics of all subbands. In another design, the criterion may be based on the channel characteristics of the designated subband.

[0080] In one design, the terminal 150 may generate channel status information based on a selected reporting scheme and report channel status information continuously at each reporting interval. This design can be used e.g. when the terminal 150 has a service duration that covers one or more reporting intervals.

[0081] In another design, terminal 150 may generate and / or report channel status information in various ways during the duration of the service. This project can be used, e.g. when the service duration is much longer than the reporting interval. Terminal 150 may send multiple packets during the service period and may select the appropriate packet format and appropriate set of spatial channels for each packet transmission. The packet transmission may include one or more reporting intervals. The designated subband can be selected for each packet transmission and may change between one and the other transmission of the packet. Subband selection may persist for each packet transmission. In this case, the designated subband index may be omitted in CQI reports sent during packet transmission.

[0082] Terminal 150 may at one time operate in one of a plurality of modes of operation, such as scheduled mode and unplanned mode. In scheduled mode, terminal 150 may be scheduled for downlink transmission and may have a fixed subband allocation that is known by the terminal and base station. In the scheduled mode, it may be desirable to correctly report the average channel status information for the allocated subband (subbands) rather than to report the channel status information for all subbands incorrectly. In unplanned mode, the terminal 150 may not be scheduled for uplink transmission and may not have a fixed subband allocation. In unscheduled mode, it may be desirable to report channel status information for as many subbands as possible. Terminal 150 can switch between scheduled and unplanned modes depending on whether the terminal is planned for transmission. For example, terminal 150 may operate in scheduled mode during its service period and may operate in unscheduled mode beyond its service duration.

[0083] In another example, a heterogeneous reporting scheme is used, and terminal 150 may send different channel status information depending on its operating mode. In scheduled mode, terminal 150 may generate the full CQI X value and the differential CQI Y value based on the total or average characteristics of the allocated subband (s). Terminal 150 may transmit the full CQI value, differential CQI value, and spatial state information using N_from + (N _s + N_Y) bits.

Terminal 150 may report channel status information at a higher rate or more frequently to update channel status information in a timely manner. For example, terminal 150 may report N_from + (N_s + N_Y) bits in each reporting interval.

[0084] In unplanned mode, terminal 150 may generate CQI information for all or multiple subbands. For example, terminal 150 may generate CQI information based on the fourth reporting scheme in Fig. 4B and may send N_from + (N_X + N_Y') + (X -1) · X_ly + N_S bits for all N subbands. Terminal 150 may also generate CQI information based on the fifth reporting scheme in Fig. 4C or some other scheme. Terminal 150 may report channel status information at a lower speed or less frequently to reduce signaling overhead.

[0085] Fig. 5 illustrates a heterogeneous reporting scheme. Terminal 150 can operate in scheduled mode between T \ and T₂. During this time period, terminal 150 may determine channel status information (e.g., average CQł) only for a selected subband (subbands) and may report channel status information more often, e.g., at a rate of one per T_t seconds. Terminal 150 can operate in an unplanned mode between 7ζ and '/' during this period of time

- 17150 can determine channel state information for all N subbands (e.g. CQI for each subband) and can report channel state information less frequently, e.g. at a rate of one in 7), seconds, where 7 '&gt; T _}.

[0086] F ig. 6 shows a design of a process 600 for reporting channel state information by means of differential coding in spatial and frequency dimensions. Spatial state information may be determined for multiple spatial channels on multiple subbands (block 612). The set of spatial channels may correspond to the set of antennas selected from among many antennas available for transmission. The spatial state information may thus indicate the selected antennas. The set of spatial channels may also correspond to a set of precoding vectors selected from a plurality of precoding coding vectors available for transmission. Therefore, spatial state information may forward selected precoding vectors. The spatial state information may indicate multiple spatial channels for each subband, for each set of subbands, or for all subbands.

[0087] CQI values ​​can be obtained for multiple spatial channels on multiple subbands (block 614). CQI values ​​may correspond to estimates of SNR or some other measure of quality of the received signal. CQI values ​​can be differential encoded in multiple spatial channels and multiple subbands to obtain differential CQI information (block 616). The differential CQI information may include any information shown in Table 1 (e.g., Y, ,Ζ, ΔΚ, ΔΔ.Υ and ΔΔΚ) and / or some other information. Differential CQI information and spatial state information may be sent as feedback (block 618).

[0088] For block 514, CQI values ​​may be encoded differently in multiple spatial channels and multiple subbands with respect to the CQI reference value. This CQI reference value may be the CQI value for the designated spatial channel in the designated subband, the average CQI value for all spatial channels in the designated subband, the average CQI value for all spatial channels and all subbands, etc. The CQI reference value can be sent along with the differential CQI information.

[0089] Differential coding in block 614 may be performed in various ways. CQI values ​​can be encoded differentially first in many spatial channels and then in multiple subbands. Alternatively, CQI values ​​may be encoded differentially first on multiple subbands and then on multiple spatial channels.

[0090] The set of spatial channels may comprise a designated spatial channel and at least one non-designated spatial channel. The subband set may include a designated subband and at least one non-designated subband. At least one differential CQI value (e.g., K) may be determined for at least one non-designated spatial channel in each subband based on the CQi values ​​for the spatial channels in that subband. For each non-designated subband, a difference (e.g., ΧΧ ") may be determined between the CQI value for the designated spatial channel in this non-designated subband and the CQI value for the designated spatial channel either in the designated subband or in the adjacent subband. A difference (e.g. Λξ,) between at least can also be determined for each non-determined subband

- one differential CQI (e.g. K) for at least one non-designated spatial channel in this non-designated subband and at least one differential CQI (e.g.} '_from , or Y_(+|) for at least one non-designated spatial channel either in the designated subband or in the adjacent subband. For each non-designated subband, the differential CQI value (e.g. ΛΆ '.) For the designated spatial channel and at least one differential CQI value (e.g. ΛΚ) for at least one non-designated spatial channel can be converted to an index that can be sent as a differential CQI information for this non-designated subband.

[0091] Fig. 7 shows a design of an apparatus 700 for reporting channel state information by differential encoding in spatial and differential dimensions. The device 700 includes means for determining spatial state information for many spatial channels in many subbands (module 712), means for obtaining CQI values ​​for many spatial channels in many subbands (module 714), means for differential coding of CQI values ​​in many channels spatial and multiple subbands to obtain differential information about CQI (module 716), and means for sending differential CQi information and spatial state information as feedback (module 718). Modules 712 to 718 may contain processors, electronic devices, computer hardware devices, electronic components, logic circuits, memories, etc., or any combination thereof. [0092] F ig. 8 shows a design of a process 800 for reporting channel state information by means of differential coding in spatial, frequency and time dimensions. Spatial state information may be determined for multiple spatial channels on multiple subbands (block 812). CQI values ​​can be obtained for multiple spatial channels on multiple subbands over multiple time intervals (block 814). CQI values ​​may be encoded differentially in multiple spatial channels, multiple subbands and multiple time intervals to obtain differential CQI information (block 816). Differential CQI information and spatial state information may be sent as feedback (block 818).

[0093] For block 816, CQI values ​​may be differentially encoded into multiple spatial channels and multiple subbands at each time interval to obtain differential CQI values ​​(e.g., Y, ΧΧ and ΖΖ) for that time interval. CQI values ​​can be encoded differentially first in multiple spatial channels and then in multiple subbands. The set of time periods may include a designated time period and at least one non-designated time period. For each non-determined time interval, differences (e.g., ΛΥ and ΛΛΚ) can be determined between the differential CQI values ​​for this non-determined time interval and the differential CQI values ​​for the previous time interval.

[0094] For block 818, differential CQI values ​​(e.g., Y, ΧΧ and ΚΚ, etc.) for a designated time interval may be sent as differential CQI information for a designated time interval. Differences in differential CQI values ​​(e.g., ΛΛ.Υ and ΔΔ7, etc.) determined for each unspecified period of time can be sent as differential CQI information for that unspecified period.

[0095] Fig. 9 is a design of an apparatus 900 for reporting channel state information by differential coding in spatial, frequency and time dimensions. The device 900 includes means for determining spatial state information for many spatial channels in many subbands (module 912), means for obtaining CQI values ​​for many spatial channels in many subbands in many time intervals (module 914), means for encoding differential values CQI in many spatial channels, many subbands, and many time intervals, to obtain differential CQI information (module 916) and means for sending differential CQI information and spatial state information as feedback (module 918). Modules 912 to 918 may contain processors, electronic devices, computer hardware devices, electronic components, logic circuits, memories, etc., or any combination thereof.

[0096] Fig. 10 shows process design 1000 for heterogeneous reporting of channel status information. CQI information may be reported according to the first reporting mode during the first operating mode, e.g., scheduled mode (block 1012). CQI information may be reported according to the second reporting mode during the second operating mode, e.g. unplanned mode (block 1014). CQI information may be sent at a first rate in the first reporting mode and may be sent at a second rate in the second reporting mode. The second speed may be slower than the first speed.

[0097] For the first reporting mode, CQI values ​​may be obtained for multiple spatial channels in at least one subband selected from the plurality of subbands available for transmission. CQI values ​​can be differential encoded in multiple spatial channels and at least one selected subband to obtain CQI information for the first reporting mode. CQI values ​​can be averaged over a selected subband (subbands), and averaged CQI values ​​over multiple spatial channels can be encoded in a differential way.

[0098] For the second reporting mode, CQI values ​​may be obtained for multiple spatial channels on the multiple subbands available for transmission. CQI values ​​can be differential encoded in multiple spatial channels and multiple subbands to obtain CQI information for the second reporting mode.

[0099] Fig. 11 shows a device design 1100 for heterogeneous reporting of channel status information. The device 1100 includes means for reporting CQI information according to the first reporting mode during the first operating mode, e.g., scheduled mode (module 1112), and means for reporting CQI information according to the second reporting mode during the second operating mode, e.g., mode unplanned (module 1114). Modules 1112 and 1114 may contain processors, electronic devices, computer hardware devices, electronic components, logic circuits, memories, etc., or any combination thereof.

[0100] The OFDMA system may be able to achieve significant profit by subband planning. However, the number of subbands in the system cannot be small. Spatial-frequency differential CQI coding (e.g., fourth reporting scheme in Fig. 4B) or spatial-frequency CQI differential coding (e.g., fifth reporting scheme in Fig. 4C) may be able to reduce feedback overhead during MIMQ-QFDMA operation . Data streams can be sent using spatial diversity, e.g. using antenna combination, precoding, etc. Spatial differentiation can lead to smaller SNR changes between adjacent subbands than for one-in-one-out (SINO) transmission. Smaller

- SNR change can make two-dimensional differential coding in spatial and frequency dimensions more efficient.

[0101] The techniques described herein can be implemented in a variety of ways. For example, these techniques can be implemented by hardware, firmware, software, or a combination thereof. For hardware implementation, the processing unit used to perform the techniques may be implemented by one or more integrated circuits for a specific application. application specific integrated Circuit, ASIC), signal processor (DSP), digital signal processing device (DSPD), programmable logic circuits (PLD), directly programmable gate matrix (FPGA), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, a computer, or a combination thereof.

[0102] For implementation by means of internal software and / or software, the techniques may be implemented by means of modules (e.g. procedures, functions, etc.) which perform the functions described herein. Firmware and / or software instructions may be stored in memory (e.g., memory 192 in Fig. 1) and executed by a processor (e.g., processor 190). The memory can be implemented inside the processor or externally to the processor. Firmware and / or software instructions may also be stored on other computer media such as random access memory (RAM), read only memory (ROM), non-volatile random access memory (NVRAM), programmable read only memory (PROM) , electrically erasable PROM memory (EEPROM), FLASH memory, compact disc (CD), magnetic or optical data carriers, etc.

[0103] The previous description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications of the disclosure will become apparent to those skilled in the art, and the general principles defined herein can be applied to other variants without departing from the scope of the claims. Thus, the disclosure is not intended to be limited by the examples described herein, but has the scope of the claims granted.

Further examples [0104] This device includes:

a processor configured to obtain channel quality indicator (CQI) values ​​for multiple spatial channels on multiple subbands, for differential encoding of CQI values ​​on multiple spatial channels and multiple subbands to obtain differential CQI information, and to send differential CQI information as information return; and memory connected to the processor.

[0105] The processor may be configured to differential-encode CQI values ​​in multiple spatial channels and multiple subbands with respect to the CQI reference value, and to send the CGI reference value together with the differential CQI information.

[0106] The CQI reference value may be the CQI value for the designated spatial channel in the designated subband or the average CGI value for multiple spatial channels and multiple subbands or the average CQI value for multiple spatial channels in the designated subband or average CGI value for the designated spatial channel on multiple subbands .

[0107] The processor may be configured to differential-encode CQI values ​​first across multiple spatial channels and then to differential-encode CQI values ​​across multiple subbands, or may be configured to differential-encode CQI values ​​first across multiple subbands and then for differential coding of CQI values ​​in multiple spatial channels.

[0108] The spatial channel set may comprise a designated spatial channel and at least one non-designated spatial channel, the subband set may include a designated subband and at least one non-designated subband and wherein the processor may be configured to send differential CQI information for each designated subband .

[0109] The processor may be configured to determine at least one differential CQI value for at least one non-designated spatial channel in each subband based on the CQI values ​​for multiple spatial channels in the subband.

[0110] For each non-designated subband, the processor may be configured to determine the difference between CQI for the designated spatial channel in the non-designated subband and the CQI value for the designated spatial channel in the designated subband and to determine the difference between at least one CQI differential value for at least one non-designated channel spatial in an undefined subband and at least one CQI differential for at least one unspecified spatial channel in the designated subband.

[0111] The processor may be configured to determine the difference between the CQI value for the designated spatial channel in the non-designated subband and the CQI value for the designated spatial channel in the adjacent subband, and for determining the difference between at least one CQi differential value for at least one non-designated spatial channel in the non-designated subband and at least one CQI differential value for at least one non-designated spatial channel in an adjacent subband.

[0112] For each non-designated subband, the processor may be configured to obtain a differential CQI value for a designated spatial channel to obtain at least one differential CQI value for at least one non-designated spatial channel, for converting the differential CQI value for the designated spatial channel to the index and at least one differential CQI value for the at least one non-designated spatial channel and for sending the index as the differential CQI information for the non-designated subband. [0113] The processor may be configured to determine spatial state information for at least one of a plurality of subbands and to send spatial state information as feedback.

[0114] The set of spatial channels may correspond to a set of antennas selected from a plurality of antennas available for transmission, and wherein the spatial state information may indicate selected antennas.

[0115] The set of spatial channels may correspond to a set of precoding vectors selected from a plurality of precoding coding vectors available for transmission, and wherein the spatial state information conveys selected precoding vectors.

[0116] This method includes:

obtaining channel quality index (CQI) values ​​for multiple spatial channels on multiple subbands;

- differential encoding of CQI values ​​across multiple spatial channels and multiple subbands to obtain differential CQI information; and sending differential CQI information as feedback.

[0117] Differential CQI encoding may include first differential CQI encoding on multiple spatial channels, and then differential CQI encoding on multiple subbands.

[0118] The set of spatial channels may include a designated spatial channel and at least one non-designated spatial channel, the subband set may include a designated subband and at least one non-designated subband, and wherein differential CQI information is sent for each non-designated subband.

[0119] Differential coding of CQI values ​​may include for each non-designated subband:

obtaining a differential CQI value for the designated spatial channel;

obtaining at least one differential CQI value for at least one non-designated spatial channel, and converting to a differential CQI index for a designated spatial channel and at least one differential CQI value for at least one non-designated spatial channel.

[0120] The invention further provides a device comprising:

means for obtaining channel quality index (CQI) values ​​for multiple spatial channels on multiple subbands;

means for differentially encoding CQI values ​​on multiple spatial channels and multiple subbands to obtain differential CQI information; and means for sending differential CQI information as feedback.

[0121] The means for differential coding of CQI values ​​may first comprise the means for differential coding of CQI values ​​in multiple spatial channels, and then the means for differential coding of CQI values ​​on multiple subbands.

[0122] The set of spatial channels may include a designated spatial channel and at least one non-designated spatial channel, the subband set may comprise a designated subband and at least one non-designated subband and wherein the means for differential coding CQI values ​​may include for each non-designated subband :

means for obtaining a differential CQI value for the designated spatial channel;

means for obtaining at least one differential CQf value for at least one non-designated spatial channel; and means for converting to the index a differential CQI value for the designated spatial channel and at least one differential CQI value for the at least one non-designated spatial channel.

[0123] A further example provides a computer medium containing instructions stored therein, comprising:

a first set of instructions for obtaining channel quality index (CQI) values ​​for multiple spatial channels on multiple subbands;

a second instruction set for differential encoding of CQI values ​​across multiple spatial channels and multiple subbands to obtain differential CQI information, and

-23 third instruction set for sending differential CQI information as feedback.

[0124] The second set of instructions may include:

a fourth instruction set for differential coding of CQI values ​​first in multiple spatial channels, and a fifth instruction set for differential coding of CQI values ​​first on multiple subbands. [0125] The set of spatial channels may comprise a designated spatial channel and at least one non-designated spatial channel, the subband set may comprise a designated subband and at least one non-designated subband, and wherein the second instruction set may comprise: a fourth set of instructions for obtaining differential CQI values ​​for the designated spatial channel in each non-designated subband;

a fifth instruction set for obtaining at least one differential CQI value for at least one non-designated spatial channel in each non-designated subband; and a sixth instruction set for converting the differential CQI value for the designated spatial channel to the index and at least one differential CQI value for the at least one non-designated spatial channel in each non-designated subband.

[0126] In a further example, the apparatus may include a processor configured to obtain channel quality indicator (CQI) values ​​for multiple spatial channels, to differentially encode CQI values ​​in multiple spatial channels to obtain differential CQI information, and to send differential information about CQI CQI as feedback, and memory connected to the processor.

[0127] The processor may be configured to obtain CQI values ​​for a plurality of spatial channels in a subband selected from a plurality of subbands available for transmission.

[0128] The processor may be configured to obtain CQI values ​​for multiple spatial channels by performing averaging over the multiple subbands available for transmission.

[0129] The processor may be configured to obtain CQI values ​​for multiple spatial channels over multiple time intervals, and to differentially encode CQi values ​​in multiple spatial channels and multiple time intervals to obtain differential CQI information for each time interval.

[0130] The device includes:

a processor configured to obtain channel quality indicator (CQI) values ​​for multiple subbands, for differential encoding of CQI values ​​on multiple subbands to obtain differential CQI information, and to send differential CQI information as feedback, and memory connected to the processor.

[0131] The processor may be configured to obtain CQI values ​​for multiple subbands for a plurality of spatial channels selected from a plurality of spatial channels available for transmission. The processor may be configured to obtain CQI values ​​for multiple subbands by performing averaging over the many spatial channels available for transmission.

[0132] The processor may be configured to obtain CQI values ​​for multiple subbands over multiple time intervals and to differentially encode CGI values ​​over multiple subbands and multiple time intervals to obtain differential CGI information for each time interval. [0133] This device includes:

a processor configured to obtain channel quality indicator (CQI) values ​​for multiple spatial channels on multiple subbands and in multiple time intervals, for coding in a manner

Differential CQI values ​​in multiple spatial channels, multiple subbands and multiple time intervals to obtain differential CQI information, and to send differential CQI information as feedback; and memory connected to the processor.

[0134] The processor may be configured to differential-encode CQI values ​​on multiple spatial channels and multiple subbands at each time interval to obtain differential CQI values ​​for the time interval.

[0135] At each time interval, the processor may be configured to first differential-encode CQI values ​​on multiple spatial channels and then to differential-encode CQi values ​​on multiple subbands.

[0136] The set of time intervals may include a designated time interval and at least one non-determined time interval, wherein for each non-determined time interval the processor may be configured to determine differences between CQI differential values ​​for an unspecified time interval and differential CQI values ​​for a previous time interval.

[0137] The processor may be configured to send differential CQI values ​​for a designated time interval as differential CQI information for a designated time interval, and to send differences between differential CQI values ​​for each unspecified time interval as differential CQI information for an unspecified time interval.

[0138] This method includes:

obtaining channel quality index (CQI) values ​​for multiple spatial channels across multiple subbands and multiple time intervals;

differential encoding of CQI values ​​across multiple spatial channels, multiple subbands, and multiple time intervals to obtain differential CQI information; and sending differential CQI information as feedback.

[0139] The set of time intervals may include a designated time interval and at least one non-determined time interval, wherein the differential CQI encoding may include the differential CQI encoding in multiple spatial channels and multiple subbands at each time interval so as to obtain differential CQI values ​​for the time interval, and may include determining differences between differential CQI values ​​for an unspecified time interval and differential CQI values ​​for a previous time interval.

[0140] Sending the differential CQI information may include sending the differential CQI values ​​for the designated time interval as the differential CQI information for the designated time interval, and sending the differences between the differential CQI values ​​for each non-designated time interval as the differential CQI information for the unspecified time interval.

[0141] This device includes:

a processor configured to report during the first mode of operation of channel quality indicator information (CGI) according to the first reporting mode, for reporting during the second mode of operation of information about CQI according to the second reporting mode; and memory connected to the processor.

[0142] For the first reporting mode, the processor may be configured to obtain CQI values ​​for multiple spatial channels in at least one subband selected from the plurality of subbands available for transmission, and for differential encoding of the CQI values ​​in multiple

-25 spatial channels in at least one selected subband to obtain CQI information for the first reporting mode.

[0143] For the first reporting mode, the processor may be configured to obtain CQI values ​​for multiple spatial channels in at least one subband selected from multiple subbands for transmission, to average the CQI values ​​for each spatial channel in at least one selected subband to obtain an average CQI value for the spatial channel, and for differential coding of average CQI values ​​in many spatial channels, to get CQI information for the first reporting mode.

[0144] For the second reporting mode, the processor may be configured to obtain CQI values ​​for multiple spatial channels on multiple subbands available for transmission, and to differentially encode CQI values ​​on multiple spatial channels and multiple subbands to obtain CQI information for the second reporting mode.

[0145] The processor may be configured to send CQI information at a first rate in the first reporting mode and to send CQI information at a second rate, slower than the first speed in the second reporting mode.

[0146] The processor may be configured to go to the first mode of operation in the case of scheduling transmissions and to go to the second mode of operation in the case of not scheduling the transmissions. [0147] A method further comprising:

reporting channel quality indicator (CQI) information according to the first mode of operation during the first mode of operation; and reporting CQI information according to the second reporting mode during the second operating mode. [0148] Reporting CQI information according to the first reporting mode may include obtaining CQI values ​​for multiple spatial channels on at least one subband selected from multiple subbands available for transmission, and differential encoding of CQI values ​​on multiple spatial channels in at least one selected subband to get CQI information for the first reporting mode.

[0149] Reporting CQI information according to the second reporting mode may include: obtaining CQI values ​​for multiple spatial channels on multiple subbands available for transmission, and differential coding of CQI values ​​on multiple spatial channels and multiple subbands to obtain CQI information in second reporting mode.