Method and device for channel feedback

FIELD: physics, communication.

SUBSTANCE: invention is related to communication systems. Method of channel scores transmission on multiple subcarriers between transmitting device and receiving device is based on the fact that transmitting device determines channel scores on multiple subcarriers, and then codes these multiple scores into at least one coded channel signal, then transmitting device sends at least one coded signal to receiving device.

EFFECT: provides efficient presentation of channel data to transmitter with the purpose of their application in closed transmission.

10 cl, 11 dwg, 1 tbl

 

The technical field to which the invention relates

The present invention in General relates to communication systems and, in particular, relates to a method and apparatus for providing channel information to the transmitter in a transmission system with many inputs and many outputs (MIMO).

The level of technology

System with many inputs and many outputs (MIMO) is a transfer method that includes multiple transmitting antennas and multiple receiving antennas, which in the long term promise a substantial increase in transmission capacity in wireless communication systems. Different strategies require transmission to the transmitting antenna array had a certain amount of information concerning the characteristics of the channel between each element of the transmitting antenna and each element of the receiving antenna, and the implementation of such strategies often referred to as closed-loop MIMO system. Getting full information about broadband channel on the transmitter side is possible by using technologies such as sensing uplink connection in full-duplex transmission time division (TDD), if the transmitter will be calibrated antenna array. However, the method of sensing uplink communication systems duplex frequency division (FDD) does not work when the system DD use repeater or when calibrating an antenna array at the transmitter fails. Thus, there is a need for effective way of ensuring full information about the channels in the transmitter, when the sensing ascending line of communication for this purpose is inefficient.

Brief description of drawings

Figure 1 - timing diagram for feedback in the TDD system;

figure 2 - timing diagram for feedback in the system FDD;

figure 3 - one effective channel information feedback;

4 is a second variant of the efficient transmission of channel information feedback;

figure 5 - example of the use of phase shift for efficient channel coding information;

6 is an example of orthogonal frequency coding channel information in the frequency domain;

Fig.7 is an example of orthogonal frequency coding channel information in the time domain;

Fig device for transmitting channel information;

Fig.9 is a block diagram showing the operation of the device Fig;

figure 10 is a device for recovery of channel estimates;

11 is a flowchart showing the operation of the device in figure 10.

Detailed description of drawings

For simplicity, the invention is shown from the point of view of providing a base station (BS) channel information when performing closed-loop transfer per subscriber station (SS). Should be the clear this invention is also applicable to scenarios where the role of the stations BS and SS reversed in relation to here. For example, the invention can be applied to the scenario where the station SS should be provided with the channel information, to be able to perform closed-loop transfer from the station SS station BS. Therefore, although this description focuses primarily on the case of transmission from station BS to the station SS, the term "communication unit source" refers to the communication unit (for example, station BS, station SS or another transceiver), which can perform closed-loop transmission on the communication unit of the addressee".

In this description, some terms are also used interchangeably. Terms such as "characteristics of the channel, profile, frequency-selective channel", "spatial-frequency response of the channel"refers to information about the characteristics of the channel, which is necessary for the base station to use the technology of closed transmission. This information about the characteristics of the channel can also be called a channel information (knowledge about the channel). The terms "signal" and "signal" are also used interchangeably. The term "subscriber device" or "subscriber station (SS) are sometimes referred to as a mobile station (MS) or simply to a mobile phone, and this is sabreena equally applicable to cases when the subscriber device is stationary or mobile (i.e. non-stationary). The receiving device may be a base station (BS), subscriber station (SS), or any combination thereof. The transmitting device may also be a station BS, station SS, station MS or any combination thereof. In addition, if the system has repeaters, repeaters, or other similar device, the receiving device or transmitting device may be a repeater, relay, or similar device. Repeater or repeater can be considered equivalent station SS, if station BS transmits feedback on the repeater/repeater. Repeater or repeater can be considered equivalent station BSBS, if the repeater is sending feedback to the station SS. The repeater can also be a unidirectional repeater, such as repeater uplink communication or relay downlink. For example, the repeater uplink communication signal is received from the uplink communication from the station SS and relays the signals or information represented by this signal station BS. The term "fast Fourier transform (FFT)" and the term "inverse fast Fourier transform (IFFT)" refers to a discrete Fourier transform (or analogy which helps to transform and inverse discrete Fourier transform (or similar conversion), respectively.

Obtaining channel information at the transmitter or the communication unit of the source is very important to take advantage of that promise these technologies use a transmitting antenna arrays, as a transfer with a maximum signal-to-noise multiple access with spatial division multiple access (SDMA) and the technology of closed transmission with many inputs and many outputs (MIMO). Two ways of obtaining channel information are feedback and a sounding channel. The sensing channel is suitable only for systems duplex time division (TDD) and is based on the use of the fact that radio frequency (RF) channels uplink communication and downlink are mutually inverse, so that station BS may obtain information about the channel downlink based on the sensing channel uplink of the mobile station. It is known that for sensing the channel for the subsequent work station BS may need to calibrate your antenna arrays uplink communication and downlink. Unlike sensing channel channel feedback suitable for systems duplex frequency division (FDD) and TDD systems without calibration antenna arrays.

The present invention proposes a method for effective before the Chi channels for feedback (for example, the multiple channel estimates for multiple subcarriers, for example, one or more antennas in the system OFDM multiplexing (orthogonal frequency division multiplexing)from the mobile station (s) station BS (this method is also suitable for the case when the mobile and base station switch roles). This method is implemented by sending station BS training sequence (e.g., pilot symbols) from each of its transmit antennas, so that the mobile station can measure (or estimate) the complex channel characteristics for each of the antennas of the BS (channel estimation can also be obtained in other ways that do not require training data, for example, channel estimation with decision or assessment of the channel "blind"). Then, each mobile station that is scheduled by the base station for this assessment (or who knows/wants to perform an assessment in any other way), encodes a channel estimation for each antenna BS (generates a channel signal), then many of these mobile stations simultaneously transmit the coded channel estimates back to the station BS to help station BS in determining channel estimates downlink.

The process of channel coding according to the present invention on a specific mobile station does not require follow what its quantization channels, which has already been done in accordance with their own precision receiver for a mobile station (for example, the standard transmission on the reverse link are binary information on a single character using the standard combinations, such as QPSK (phase shift keying with Quaternary phase signals), while the present invention can provide essentially no quantized channel estimates (e.g., need not be limited to four values of the combination of QPSK and limited to its own processing accuracy when receiving and transmitting to the mobile station)); rather, this process provides an efficient (from the point of view of the use of the band) the consolidation of a quantity measured channels (e.g. channels from each antenna station BS to one or more antennas of the mobile station) in a single channel signal, which can also be called a channel coded signal for transmission to station BS. Many mobile stations can transmit their encoded channel signals, using the same time/frequency resource in the way SDMA. Then station BS uses many of their receiving antennas for selecting encoded channel signals from each mobile station then determines channel estimates through cancellation coding. Note that in the MMO system for mobile stations with multiple antennas, each antenna may transmit different from other encoded channel signal (for example, signal as a result of encoding channels from all antennas of the BS antenna of the mobile station that transmitted the encoded channel signal). Of course, the transmission type is MIMO channel encoded signal from one mobile station according to the way SDMA may overlap the transmission of the encoded channel signal from another mobile station. By efficient encoding of the channel estimates and the use of technology SDMA and/or MIMO when sending on uplink communications can provide a very high efficiency of use of the band for channel feedback. This invention provides effective feedback wideband channels in the frequency domain (for example, on the set of subcarriers of the OFDM system) or in the time domain (for example, by replacing characters of data time-domain samples of the channel signal) through selective combination of SDMA, MIMO, channel estimation of multiple sources, scrambling to avoid redundant values of the ratio of peak power to average power, as well as selection of the form of the pilot signal.

1 shows an exemplary timing diagram for feedback in the communication system TDD (DL - downward communication line, UL - rising line), where the base station requests a channel information to perform closed-loop transmission (will lock the th loop) of a certain type by using the transmit adaptive antenna array (TxAA) according to the present invention. For uplink communication can be used technology acceptance SDMA, so many mobile stations can send their feedback data using the same frequency-time resources.

First station BS sends training data (e.g., pilot symbols) towards the end of the frame of the downlink (in fact, the training data can reside anywhere in the frame of the downlink, but the delay due to the feedback is reduced, if the training data is sent at the end of the frame downlink). When station BS has multiple transmit antennas, it can run many programs, for example, the first transmission from the first transmitting antenna, a second transmission from the second transmitting antenna and so on (a lot of gear), where many transmission preferably includes pilot symbols, which allow the station SS to estimate the channel in the set of subcarriers for each of the transmit antennas station BS. Many transmission can be performed simultaneously, preferably orthogonal/distinguished pilot sequences between the antennas (for example, using different sets or sets of subcarriers with different antennas) or can be performed separately, but preferably, these transmissions were close in time. Then each mo is strong station, the requested station BS to send channel information, estimates a channel for each transmit antenna station BS (for example, by defining multiple channel estimates for multiple subcarriers), encodes channel estimation, creating a channel coded signal (creates or generates a channel signal), and then reports channel information by sending (transmission) of the encoded channel signal to the base station during transmission on the uplink communication. In one embodiment, the channel estimation code in order to provide the opportunity to make a channel estimates from multiple antennas of a station BS and/or multiple receiving antennas of the station's SS at the time interval of one symbol. Note that in one embodiment, the channel estimation send together with pilot symbols used for channel estimation uplink communication station BS (channel estimation of uplink communication used by station BS, to enable its reception antenna array to separate the channel feedback uplink communication for multiple mobile stations, and determines the encoded channel estimates from each mobile station). The pilot symbols can form the signal channel sensing (e.g., pilot symbols on a set of OFDM subcarriers)to give an opportunity to assess the channels upward from the connection station BS. Station BS uses the channel information feedback to perform closed-loop transmission (e.g., transmission TxAA) for downlink, after ascending line (closed-loop transfer (closed-loop) is preferably performed at a very close spacing of the frame of the downlink, in order to minimize the change in the channel between point measurements and using this measurement, but the invention is also applicable to cases where the delay is longer)). Since the channel information feedback is not necessary to quantize obtaining a standard combination of symbols (e.g., QPSK), resolution, and dynamic range channel information can be improved (e.g., essentially without quantization) compared to standard schemes. Thus, in one embodiment, the channel estimation, the transmitted feedback, essentially no quanthouse. In other embodiments, channel estimation can be converted into one of a predefined set of values (for example, the closest predefined set of complex values), may be limited or may be set to zero if its magnitude is below a specific value, etc.

Figure 2 shows an exemplary timing diagram for feedback in the communication system FDD (DL - downward communication line, UL - rising line), where station BS op is th same requests channel information, to perform closed-loop transfer (for example, TxAA). For uplink communication can be used technology acceptance SDMA, so many mobile stations can send their feedback data using the same frequency-time resources.

The operation in this case is similar to the TDD mode, but in the FDD mode, the delay between the measurement channels and the use of station BS channel estimates for the downlink can be significantly reduced in comparison with the TDD mode by simultaneously transmitting on the downlink and uplink communication. For simplicity, assume that the feedback mechanism downward communication and upward communication line FDD system uses the same modulation method (e.g., OFDM) with the same bandwidth. However, the proposed feedback mechanism easily extended to the case when in the uplink communication and downlink use different modulation methods and/or different frequency bands. In addition, the invention involves the use of multiple transmission modes for uplink communication, e.g., IFDMA, CDMA, TDMA with one carrier or their combination for the regular transmission of data in the ascending line (any of the modes, providing low peak-to-average), and OFDM/OFDMA for transmission back on the connection (providing the transmission of feedback of the complex channel characteristics in the frequency domain). In this case, transmission of feedback, it is preferable to multiplex in time or in frequency together with regular data transmissions. Thus, the present invention can transmit channel signal, using a different modulation method different from that used for transmission of other data from the communication unit of the recipient.

Note that the plot of the feedback frame uplink communication, shown in figure 1 and figure 2, consists of two time intervals of the OFDM symbol. The first period of the transmission of characters is intended for sending pilot symbols of each mobile station (for example, the signal channel sensing), which is used for channel estimation, and the second transmission period character is used to send data feedback to help the communication unit source in determining channel estimates for the multiple subcarriers.

This possible option for feedback shown in figure 3, where each rectangle corresponds to one subcarrier in one OFDM symbol. Another option for feedback, as shown in figure 4, where each rectangle corresponds to one subcarrier in one OFDM symbol, requires only a single OFDM symbol by mixing the pilot symbols (e.g., signal channel sensing) data feedback. The mixture shown in figure 4, contains estatoe multiplexing, but you can also use a mixture of other types. Obviously, any mixture of the pilot signal and the channel signal, for example, the dispersal of pilot symbols and samples of the channel signal according to the multitude of symbolic intervals. In addition, the pilot symbols may not explicitly be sent with a channel signal, for example, when the communication unit source uses the channel estimates from normal traffic data for discovery channel signal transmitted from the communication unit of the recipient.

Compared with the strategy of re-use (or reversibility) of the channel (i.e., in the TDD mode mobile station probes upward communication line and station BS relies on the reversibility between channels uplink communication and downlink) and other known technologies proposed method of feedback has the following advantages:

1. The proposed method of feedback can be used as a mode of TDD and FDD mode.

2. The proposed method is implemented in a mobile unit is much simpler than the methods based on dictionaries codes and vector quantization.

3. Using the proposed method feedback in TDD mode does not require calibration of the antenna at station BS or the mobile station.

4. The proposed method feedback provides a mechanism to channel the reverse swazis systems with TDD relay in the ascending line (channel sensing uplink communication is not possible, because the mobile station does not transfer directly to a station BS).

5. The proposed method of feedback can be very useful during calibration of the antenna array. For example, the proposed method of feedback can be used to make the inversion channel from the station SS station BS.

6. The proposed method feedback.we will work even in the case when antenna arrays uplink communication and downlink on station BS are different from each other.

7. The mobile station may use the pilot signals broadcast on the downlink for determining a composite channel (i.e., the effective channel perceived by the mobile station, which is a combination of scales transmission and the actual RF channel), if the mobile station knows how station BS calculates these weight transfer. The reason for this is that the mobile station knows the channel that station BS uses to calculate the weights of the transmission, and this channel is not suitable for channel sensing uplink connection.

Below are detailed some aspects of the proposed method of feedback. Let station BS has Mbantennas (for both descending and ascending lines); and further investigated two cases for mobile stations: 1) case, when the mobile station u has only one transmitting antenna and M m,ureceiving antennas, and 2) the case when a mobile station u has Mm,utransmitting and receiving antennas. (Note that the way feedback is applicable to any number of transmit antennas at the mobile station. Also the way of feedback easily extended to the case when the base station has a number of receiving antennas than the number of transmitting antennas). If we assume that the downward communication line OFDM uses the K subcarriers, the received signal for mobile station u in his reception antenna m for subcarrier k (0kK-1) and the point in time b to symbol is specified as:

where Hu,m,l(k,b) - channel in the frequency domain from the antenna l station BS (for example, the communication unit source) to m-th receiving antenna of the mobile station u (for example, the communication unit receiver on subcarrier k at time b symbol; Xl(k,b) - training symbol transmitted from the l-th antenna station BS, and Nu,m(k,b) is additive noise with power. Note that the time index b is used to specify the symbolic time of pilot symbols (can be multiple values of b, if, for channel estimation, you need more than one OFDM symbol).

The mobile station can run block channel estimation from multiple sources according to the signal to determine channel estimates in point b, preferably for two or more values of k (defining multiple channel estimates for multiple subcarriers). Note that channel estimation typically have complex values (representing both amplitude and phase). Station BS may transmit orthogonal pilot signals from many of its antennas to give the ability to perform simple channel estimation for multiple antennas at the mobile station. You can also use other methods of channel estimation (e.g., decision support, iterative etc). Then the mobile station code channel information to generate channel signal based on one of the following methods.

Method 1: Partial in-time feedback for channels in the frequency domain

In this way feedback use linear phase shift/sawtooth change (also known as phase shift Steiner) to encode the measured channels (channel estimates from the set of transmitting antennas, so that the channels in the time domain are orthogonal (i.e., channel estimates are shared in the time domain). An example of the resulting representation in the time domain encoding with phase shift channels in the frequency domain is shown in figure 5 for Mbtransmitting antennas at the base station for mobile hundred is tion with one antenna. This encoding makes channels for each transmitting antenna orthogonal (distinguishable) in the time domain. As you can see, the corresponding phase shift leads to the fact that the channels in the time domain for each transmitting antenna of the base station occupy different areas of the temporal region. According to this method of feedback mobile station code channel estimates from each BS antenna for efficient transmission by creating a subsequent signal uplink communication (i.e., the encoded channel signal or the channel signal) for mobile station u with one transmitting antenna (note that the time index d is used to indicate the position in time of the feedback uplink communication, which happens at some point after the temporary index b, where pilot symbols are transmitted from station BS in order to have the possibility of estimating the channel at station SS):

where Su,m,l(k,d) - the coding sequence for the channel estimates of the user u and βu- scaling (scale factor)required to make the average transmit power (averaged over all frequencies and, if applicable, time) Zu(k,d) is equal to (or some other desired power level). It is important to have unified the scaling for all channel estimates for the one mobile station, so that the relative power levels between any channel estimates remained. If scaling is not necessary, it can be eliminated by setting βu=1. Note that, if Mbis two or more, then station BS has multiple antennas, and determining the multiple channel estimates for multiple subcarriers may include defining a set of channel estimates for each of the multiple subcarriers based on a variety of transmission (for example, each transmission from the other antenna)received from the communication unit of the source.

One example of the coding sequence is the following signal, which has two aspects. The first aspect is the phase shift of Steiner, which allows you to split the channels in the time domain, and the second aspect is scramblers sequence:

where qu(k,d) - any known/scramblers sequence (for example, a random sequence with a constant module, such as a random BPSK symbols), and αu- shear factor for user u (e.g., αu=Mm,uMb). Note that the use of scramblers sequence is an important aspect of the invention, since the multiplication of the channel estimates on scramblers sequence prevents the appearance is excessively large relations peak-to-average (PAPR) in the transmitted signal uplink communication (i.e., the IFFT transformation for Zu(k,d)), especially for certain conditions in the channel (e.g., channels with a uniform sinking).

When a mobile station u has multiple transmit antennas, it is possible to transfer data feedback type MIMO, and then the encoded channel signal (for m-th transmitting antenna to the mobile station, u) is defined as:

where βu- scaling required to make the average transmit power (averaged over all frequencies, all mobile antennas and, if applicable, time) Zu,m(k,d), is equal to (or some other arbitrary power level). The coding sequence of the Su,m,l(k,d) is defined as:

where qu,m(k,d) - any known/scramblers sequence (for example, a random sequence with a constant module, such as a random BPSK symbols), and αu- shear factor for user u (e.g., αu= Mb).

Note that when using equation (2) or (4) the channel frequency domain on subcarrier k is a feedback on subcarrier k. In the TDD system, this means that if k subcarriers freezes, then the feedback channel will be sent on subcarrier with low amplitude. To avoid this the problem, an additional aspect of the invention includes the alternation or modification of the order of Zu(k,d) or Zu,m(k,d) frequency for effective scrambling feedback frequency. Note that interleaving should be performed encoded channel signal Zu(k,d) or Zu,m(k,d)instead of the channel estimates, and before applied phase shift. If to send data feedback for uplink communication using multiple OFDM symbols, then it can be beneficial alternation in time in addition to the alternation frequency especially when different channels have different average power (for example, for the two channel estimates, each of which has K values to be transmitted back through the two OFDM symbol in each OFDM symbol must be transmitted half of each channel assessment (K/2 values of each evaluation), so that total transmit power is the same for each OFDM symbol).

Also note that equations (2) and (4) can be modified for distribution to the case where the pilot signal is mixed with the feedback signal, as shown in figure 4. These equations can also be modified to encode channels when the frequency and/or modulation type downlink (for example, one carrier) is different from the uplink connection.

Method 2: Orthogonal-frequent the percentage feedback channel in the frequency domain.

In this way the measured channels downlink are separated in the frequency domain, so that they do not create interference. An example of this encoding method is shown in Fig.6 for Mbtransmitting antennas at station BS and one receiving antenna at the mobile station, where each rectangle in the figure corresponds to one subcarrier in one OFDM symbol. As you can see, the channels in the frequency domain for each antenna are transferred on different subcarriers (e.g., display or encoding of channel estimates for a particular antenna in a pre-defined set of subcarriers), and therefore do not cause mutual interference. To restore the channel estimates for all subcarriers station BS you want to interpolate channel estimates. 6 can be modified for distribution to the case where pilot signals are mixed with the data feedback (for example, by analogy with figure 4). In equation form channel coded signal for this kind of encoding channels in the frequency domain (when the mobile station u has only one transmitting antenna) is specified as:

where (n)Nmeans n modulo N; δ(n) is equal to unity if n is zero, and zero otherwise; qu(k,d) - any known/scramblers sequence (e.g., random posledovatelnosti permanent module, such as a random BPSK symbols), and βu- scaling required to make the average transmit power (averaged over all frequencies and, if applicable, time) Zu(k,d), is equal to (or some other desired power level). As in the case of separability in time, qu(k,d) helps to avoid large values of the ratio of peak power to average in the transmitted signal uplink communication. Also, as in the case of separability in time for scrambling the encoded signal according to the frequency before transmitting, you can use the alternation Zu(k,d). When a mobile station u has Mm,utransmitting antennas, the encoded channel signal to the transmitting antenna m of the mobile station is specified as:

where qu,m(k,d) - any known/scramblers sequence (for example, a random sequence with a constant module, such as a random BPSK symbols), and βuthe scaling required to make the average transmit power (averaged over all frequencies, all mobile antennas and, if applicable, time) Zu,m(k,d) is equal to (or some arbitrary power level.

Note that equations (6) and (7) for simplicity, can be written without a time index file is in explicit form, namely

Note that if Mbis 2 or more, the definition of the multiple channel estimates for multiple subcarriers may include determining channel estimates for the first set of subcarriers corresponding to the first transmitting communication unit source (for example, from the first antenna, and determining channel estimates for the second set of subcarriers corresponding to the second transmission unit communication source (e.g., from the second antenna).

Method 2 can also be attributed to the type of razdelimosti associated with thinning of subcarriers as a result of the application of the Delta function is the location of zeros in some subcarriers, so that channel estimates are sent back to a thinned set of subcarriers. Another set of channel estimates (e.g., for different values of l or to another mobile station) can be assigned to subcarriers set to zero, as can be seen from Fig.6). Method 1 can also be attributed to the method that uses the separability based on the cyclic shift since the sawtooth phase shift in equation 5 based on αuintroduces a cyclic shift in the representation of the channel in the time domain (see figure 5).

From the mathematical representations of methods 1 and 2 can be seen that both of these techniques create a channel signal on the new set of channel estimates. Because its structure channel signals include the multiple channel estimates, we can assume that the channel signals contain a combination of multiple channel estimates. Also qu,m(k,d) and Su,m,l(k,d) are known sequences, and the channel signals can be considered as containing channel estimation, modulated by a known sequence. For example, qu,m(k,d) preferably is a binary sequence (e.g., BPSK), but can be any known sequence.

After creating the channel signal can be sent to provide information about the channel or to help the communication unit source in determining channel estimates for the multiple subcarriers.

Method 3: Orthogonal-frequency feedback channel in the time domain

An additional way to give feedback is to make the estimated channel time domain back into the frequency domain or in the time domain. Essentially this method is similar to the method described in the previous section, to make an evenly spaced in the frequency domain channel except that the channel estimation in the frequency domain are replaced with the channel estimates or characteristics in the time domain. Thus, 6 is still valid, but the channel on this drawing now hereafter which includes the channel in the time domain. Another possible variant is shown in Fig.7, where each channel characteristic in the time domain for a single transmitting antenna and the antenna of the mobile station is sent in a continuous block of subcarriers. Each rectangle in the figure corresponds to one subcarrier in one OFDM symbol. In equation version of the feedback as a continuous block (when a mobile station u has one transmitting antenna) is expressed in the form:

for 0nL-1, 1lMb, 1mMm,u

where L is the length of the channel time domain, qu(k,d) is any sequence (for example, a random sequence with a constant module, such as a random BPSK symbols), and βu- scaling required to make the average transmit power (averaged over all frequencies and, if applicable, time) Zu(k,d)equal to one (or some required value). When a mobile station u has multiple transmit antennas, the encoded signal to the transmitting antenna m of the mobile station is specified as:

for 0nL-1 and 1lMb

where qu,m(k,d) is any sequence (for example, a random sequence with a constant module, such as a random BPSK symbols), and βu- scaling required to generate the, to make the average transmit power (averaged over all frequencies, all mobile antennas and, if applicable, time) Zu,m(k,d) is equal to (or some other arbitrary value).

Note that all the described coding scheme does not necessarily limit the dynamic range of the encoded channel. It is expected that the channels are inherently limited dynamic range, but in some implementations, the mobile station need to be encrypted channels were narrower dynamic range, suitable for the scheme and the implementation of the transmitter. Thus, the encoded channel signal can be further processed, so that the resultant signal is consistent with the requirements of the transmitter of the mobile station to the dynamic range. There are various technologies to ensure that the encoded channel signal dynamic range, such as (but not only): the restriction of the encoded channel signal so that it does not exceed a certain value or voltage; mapping the encoded channel signal in a certain combination of symbols; and zeroing of the encoded signal for the samples whose amplitude is below the threshold. Also, these processing methods can be applied directly to the channel estimates to create the compound of (channel) feedback signal (for example, ifbelow the threshold value, it can be reset, or if its value is above the threshold value, it is possible to limit, or you may need the quantization of its amplitude and/or phase). Another method that can be used either to control the dynamic range, or for the improvement of performance in terms of noise is to perform companding values. Not necessarily on the side of the receiver station BS operation kompaktirovaniya can be reversed to restore some part of the dynamic range.

For ease of explanation of some aspects of the invention have been described above, with a view to provide information about the channels for all K subcarriers of the OFDM system or thinned subset of K subcarriers of the OFDM system. This situation may occur because the pilot symbols from station BS usually allow you to evaluate all subcarriers at the station MS. But even under these conditions station MS may be requested to transmit feedback information about the channel only for a subset of subcarriers (for example, selected subcarriers or subcarriers selected in a particular band of subcarriers). In this case, you do not want subcarriers used station MS for sensing channel of the ascending line is communication and transmission of the encoded channel signal, coincided with subcarriers, the channel information which is requested station BS, while station BS clear how subcarriers corresponds to the feedback. In one example, when feedback is transmitted channel information of the adjacent block of subcarriers (i.e., subpoles), to create the encoded channel signal can be applied all three of the above-mentioned method. But in this example, the third method (i.e., orthogonal-frequency feedback channel in the time domain) is preferably simulates the frequency response of subpolicy with the channel in the time domain, which has a larger channel spacing than in the case of full bandwidth. In another example, when feedback is transmitted channel information for a set of disjoint subcarriers station MS can, one at a time, forward, back channel associated with each antenna station BS for each subcarrier, or do it at the same time as when the transmission type is MIMO.

Also, there may be some environments where the encoded channel signal is received in conditions of low SNR (signal-to-noise), or C/I (ratio of carrier power to the noise level). To improve the quality of feedback mobile station may re-transmit the encoded channel signal (in time and/or frequency). Alternatively, instead of what about the repetition of all of the encoded channel signal before generating the encoded channel signal can be repeated channel estimation. For example, in orthogonal-frequency method (6) on the subcarrier, where it is assumed feedback channel for the antenna 1 on the subcarrier-Mb"may be re-sent "channel for antenna 1 on subcarrier-0". Compromise quality improvement subcarrier-0 is increased coefficient decimation in the frequency domain, because the channel on subcarrier-Mbwill not be aware of. In addition to these technologies improve the quality of feedback you can reduce the impact of noise on the feedback channel, applying the block back kompaktirovaniya (or extender) to valuesat station SS (preferably with limited output value) and provided on the base station BS inverse operation after data reception feedback. It is possible to calculate the characteristic of the input-output expander thus to improve the ratio SNR or other indicator of the quality of the output of the inverse operation at station BS (e.g., SNR or MSE (mean square error)averaged over frequency, gain directional steps in the formation of the beam on the basis of the processed data feedback and so on).

Note that in alternative embodiments of the invention instead of the channel estimationfor any of the methods mentioned above provide feedback can pic latisa other signals. Note that methods 1 and 3 may require that the signal from the feedback in the frequency domain, had an equivalent representation in the time domain with a finite time range. For example, to facilitate the implementation of these technologies, such as calibration of an antenna array can be sent back analogues (inversion) channels. Another example is the transmission of frequency-selective level SNR on each subcarrier for use on station BS according to the technology of capacitive load.

Receiving and decoding data feedback, when all mobile stations have the same transmitting antenna

Station BS receives the signal containing the channel signal (Z), and the channel signal has multiple channel estimates, as described above, where the set of channel estimates comprises at least one channel estimate for each of the multiple subcarriers. Note that many carriers do not need to have each of subcarriers in the OFDM system, it can be a subset of subcarriers, for example, a set of adjacent subcarriers or the set of non-adjacent subcarriers (for example, evenly spaced subcarriers), and the set of subcarriers may cover any area of the channel bandwidth. Station BS estimates the receiving channel for the received signal, preferably on the basis of the helot signal, which is taken together with a channel signal, and restores the assessment for a variety of channel estimates based on the received signal and the estimated reception channel. The following is a detailed description of the sample, revealing some aspects of the above-described operations for the case when station BS receives Nuchannel signals.

Numobile stations transmit their encoded sequences at the same time, and Mb×1 adopted signal vector representing the received station BS channel signals, is defined as:

where Gu(k,d) - Mb×1 (receiving) channel vector uplink communication on subcarrier k at time d for mobile station u, and N(k,d) is additive Gaussian noise with correlation matrix given as(Inthe matrix is the identity n×n).

To recover estimates of the signalsuplink connection of each mobile station station BS can use the following integral weight given MMSE (minimum mean square error) for the mobile station u:

where- (reception) channel estimation of uplink communication, obtained by processing the pilot symbols sent from each of the mobile station and the station has received BS), for the evaluation of the receiving channel. Note that channel estimationusually are complex and can be called the estimated complex channel gain. Evaluation of signal uplink connection for mobile station u is defined as:

Using this estimate together with the coding strategy for mobile station u (i.e., are sent channel estimation in the frequency domain or in the time domain and whether the encoding with the separation in time or orthogonal frequency coding that will be known station BS, if station BS indicates station MS in a message about what specific method is used to provide feedback), the base station may receive (restore) evaluation channels, which were obtained by measurements on each mobile station and used to create the channel signal transmitted by the mobile station. Note that in this step, to help get the gain, giving the excess noise plus interference from channel encoding for multiple antennas station BS together, you can use the standard procedure of channel estimation. Now station BS has a channel estimate downlink for use in operations TxAA at time t (for total delay is mainly the Oh connection for t-b OFDM symbols).

An example of receiving and decoding data feedback, when all mobile stations have multiple transmitting antennas

Numobile stations transmit their encoded sequence with all their transmitting antennas at the same time, and Mb×1 adopted signal vector at station BS is defined as:

where Gu,m(k,d) - Mb×1 channel vector uplink communication on subcarrier k at time d for the m-th transmitting antenna of the mobile station u, and N(k,d) is additive Gaussian noise with correlation matrix given as(Inthe matrix is the identity n×n).

To recover estimates of the signalsuplink connection of each mobile station station BS uses the following compound weight given MMSE for the transmitting antenna m in the mobile station u:

wherechannel estimation ascending line obtained from the pilot symbols sent from each mobile station.

Evaluation of signal uplink communication m-th transmitting antenna for mobile station u is defined as:

Using this estimate together with the coding strategy for mobile station u (i.e., sent lisanally estimation in the frequency domain or in the time domain, and if the encoding with the separation in time or orthogonal frequency coding) the base station BS can obtain estimates of the channels, which were obtained by measurements on each mobile station. Note that in this step, to help get the gain, giving the excess noise plus interference from channel encoding for multiple antennas station BS together, you can use the standard procedure of channel estimation. Now station BS has a channel estimate downlink for use in operations TxAA at time t (for total feedback delay for t-b OFDM symbols).

Receiving and decoding data feedback in relay

As was described earlier, block, receiving the feedback signal, which may be a repeater/repeater. In this case, the operation/processing of the received channel signal is performed in the relay, basically similar to the one that takes place at station BS.

Another aspect of the present invention is a methodology for signal transmission, which supports the methodology effective channel feedback. Approximate option is a draft specification IEEE 802.16e/D5, where this methodology allows subscriber stations (SS) to transmit the channel sounding signals in the ascending line of communication to date is the ability of the base station to estimate a channel characteristic of uplink communication between each SS antenna and each antenna of the BS. This methodology channel sensing uplink communication from the section 8.4.6.2.7.1 project specifications IEEE 802.16e/D5 can be modified to enable and support methodology for effective transmission of feedback signals according to the present invention. The idea is to use the same methodology channel sensing uplink communication from the section 8.4.6.2.7.1 project specifications IEEE 802.16e/D5, allowing station BS to estimate channel characteristics of the ascending line. However, for each symbol in the zone sensing (section frame uplink communication (UL), where station SS transmit sounding signals), and each character interval, which sends a sounding signal lines UL, may be followed by a symbol interval in which the feedback signal (CH signal) may be sent by the stations of the SS, which had been transmitted probing signals. Sounding signals for the line UL allow station BS to estimate the UL channel, which is then used to estimate the transmitted feedback signals (channel signals)that embody the methodology of effective feedback according to the present invention.

Below is described the first example of enabling methodology for effective feedback according to the present invention in the communication system defined in the project specifications IEEE 802.16e/D5. Methodology to the national sensing uplink communication section 8.4.6.2.7 IEEE 802.16e modified by inclusion, in addition to the probing signal, commands, enabling direct transmission channel coefficients DL (downlink) (channel estimates for the multiple subcarriers. This modification extends the transmission channel sounding signals for the line UL, allowing you to implement the transfer of closed-loop systems FDD and TDD systems, which are not calibrated transceiver antenna array station BS. This modification consists in the introduction of additional fields in the message UL_Sounding_Command_IE() (command sensing line UL), which can be configured station BS and transmit to the station SS to specify or issuing commands about whether or not together with the excitation signal in the sensing area to be transmitted channel coefficients. When using this functionality for direct transmission channel coefficients of the probing signal is set by the command sensing, allows station BS to estimate the UL channel, which station BS then uses to estimate channel coefficients DL, sent by station SS on the site feedback probing signal. Then these estimated channel coefficients DL can be used by station BS to perform closed loop (closed-loop) transfer. One example of a message that can be configured and transmitted by the station BS indication or command station SS, that sent the resultant feedback signal is as follows:

Table 1

UL_Sounding_Command_IE()
SyntaxSizeNotes
UL_Sounding_Command_IE(){
Extended UIUC4 bitsH
Length4 bitsVariable
Sounding_Type

(type sensing)
1 bit0=type a

1=Type B
Sending message flag on the sounding1 bit
If (Sounding_Type==0){
The inclusion of a symbol feedback0=No feedback symbols

1=Enable symbol feedback

(See 8.4.6.2.7.3)
Num_Sounding_symbols3 bitsThe total number of symbols sensing, distributed in the command sensing, ("000") to 23=8 ("111")
Type of razdelimosti1 bit0: takes all subcarriers in the selected bands;

1: is thinned subcarriers
If (type razdelimosti==0){(use section-lamoste on the basis of cyclic shift)
The index P of the maximum cyclic shift2 bits00:P=4;

01:R=8;

10:R=16;

11:P=32
} otherwise {(based on separate treatment of emoti based thinning)
The value of the parameter D thinning3 bitsSounding every D-th subcarrier in the distribu-tion sensing. The value of the parameter D thinning is equal to 2 raised to the (2 plus this value), that is, 4,8,... to the maximum of 64.
Randomization shear thinning1 bit0=no randomization shear thinning

1=the shear thinning defined pseudo-random way
}
For (i=0; i<Num_Sounding_symbols;i++){
The character index of the sensing3 bitsThe character index in the sensing area, from 1 (bits "000") to 23=8 (bits "111")
The number of CID (broken-indicator client)4 bitsThe number of CID, joint-but using this distribution sensing
For (j=0; j<quantity. CID;j++){Ȁ
Shortened basic CID12-bit12 younger (LS) bits basic CID values for MSS (mobile SS)
The initial frequency band7-bitOf up to 96 lines (depending on the size of the FFT)
The number of frequency bands7-bitAdjacent strips, used for sensing
How to assign power2 bits0b00=equal power;

0b01=reserved;

0b10=depending on the mutual interference. The power limit for each subcarrier;

0b11,=depending on the mutual interference. The total power limit
Increasing capacity1 bit0=no increase capacity

1=increased power
The flag of the plurality of antennas1 bit0=MSS probes only the first antenna

1=MSS probes all antennas
If (type razdelimosti==0){
The index m cyclic shift in time5-bitCyclically shifts the symbol in the time domain by the number (from 0 to P-1)multiple of N/P where N is the FFT size, and P=the index of the maximum cyclic shift
} otherwise{
Shift d thinning6-bitThe relative initial position of the shift for the first subcarrier used for sounding-tion, the distribution sensing
}
Frequency2 bits00=single command, not periodic, or over-committing frequency

01=repeat sounding of once per frame until the end of the

10=repeat commands, one per 2 frames

11=repeat commands, one per 4 frames
}
}
} otherwise {
Permutation2 bits0b00=PUSC permutation

0b01=FUSC permutation

0b10=optional FUSC permutation

0b11,=permutation neighboring subcarriers
IDcell6-bit
Num_Sounding_Symbols3 bits
for

(i=0; i< Num_Sounding_Symbols; i++){
The number of CID7-bit
For (j=0; j<quantity. CID;j++){
Shortened basic CID12-bit12 LSB of basic CID values for station MSS
Complete subchannel offset7-bitSubchannel with the minimum index that is used to transfer package, starting from subchannel 0
The number of subchannels3 bitsThe number of subchannels with consecutive indices used to transfer the packet.
Frequency2 bits00=single command, not periodic, or over-committing frequency

01=repeat sounding once per frame until the end of the

10=repeat commands, one per 2 frames

11=repeat commands, one per 4 frames
The method of assignment

power
2 bits0b00=equal power;

0b01=reserved;

0b10=depending on the mutual interference. The limited value of power for each subcarrier;

0b11,=depending on the mutual interference. The total power limit
Increasing capacity1 bit0=no increase capacity

1=increased power
}
}
}
Fillingre-MennoZero-fill IE to the border of the octet. Bits must be set to 0
}

Note that commands in IE can specify a special character index and a special type or method of razdelimosti of the many ways to build the channel signal. If the "Enable character feedback" set to 1, then the team UL_Sounding_Command_IE() allows or causes the station SS (MSS) to perform direct transmission channel coefficients DL station BS with signal sensing line UL. This functionality provides a base station status information channels downlink both FDD and TDD systems, which are not calibrated transceiver antenna array station BS. In the presence of such functionality or allow command channel coefficients DL coded, as described below, and transmitted to one or more symbols of the feedback, which follow directly after each symbol used for transmitting the probing signal line UL. In this case, the sounding signal line UL is used by station BS for channel estimation line UL, so the characters feedback, PE is dannie stations SS, can be estimated station BS. Then the coded symbols of the feedback can be used to initiate closed-loop transfer down the line.

Depending on the value of the field/team type razdelimosti distinguish two cases. In the first case, if the type of razdelimosti - 0 (separability with a cyclic shift of the probing signal), then for each probe symbol, distributed command UL_Sounding_Command_IE()should one character feedback. This symbol feedback station antenna SS, which transmits the probe symbol will transmit the encoded feedback signal, which occupies the same bandwidth sensing allocated for signal sensing. The encoded feedback signal for u-th station SS (where u is the index of the cyclic shift in the command sensing line UL) is determined for the two cases. The first case refers to the situation when the station SS is one transmitting antenna, but a number of receiving antennas, and she reported the team IE sensing for sensing all of the antennas (the flag of the plurality of antennas is set to 1). In this case, one transmitting antenna transmits a sounding signal, suitable for a single transmitting antenna in the probe symbol and transmits the following signal feedback in the next symbol interval:

where- estimated channel coefficient (channel estimation) line DL between the l-th transmitter antenna station BS and m-th receiving antenna u-th station SS for subcarrier k; βu- scaling required to make the average transmit power of the feedback signal (averaged over all frequencies) Zu(k)equal to one; su(k) - probing sequence (known sequence) of section 8.4.6.2.7.1; Mm,u- the number of receiving antennas on the u-th station SS; αu- Mm,uMband Mb- the number of transmitting antennas station BS.

The second case to razdelimosti type 0 refers to the situation when the station SS is the number of transmitting antennas equal to the number of receiving antennas. In this case, the encoded feedback signal, transferable antenna station SS, which is assigned the index u of cyclic shift in the command sensing line UL, are in the form:

where- estimated channel coefficient line DL between the l-th transmitter antenna station BS and antenna station SS, which is assigned the index u of cyclic shift in the command sensing line UL for subcarrier k; βu- scaling required to make the average transmit power signal is Ala feedback (averaged over all frequencies) Z u(k)equal to one; su(k) - probing sequence (known sequence) of section 8.4.6.2.7.1; αu- Mband Mb- the number of transmitting antennas station BS.

When using the command sensing line UL of razdelimosti type 1 (separability with thinning in the probing signal) for each allocated sounding symbol follows several characters of feedback, the number of which is equal to the number of antennas of the station BSBS. In this case, the antenna station SS, which broadcasts on subcarrier k of the probing signal, will transmit channel coefficient line DL for the i-th antenna of the base station antenna station SS for the k-th subcarrier to subcarrier k of the i-th symbol of feedback following a distributed probing character. According to equation station SS, which transmits a sounding signal on subcarrier k of the probe symbol will transmitin the l-th symbol followed by a sounding symbol, wherechannel coefficient line DL from the l-th antenna station BS to the specified antenna station SS.

Note that the sensing line UL is the message that station BS configures for a communication unit of the addressee (SS), and this message among other things, specifies the specific method used to polictically estimates from the communication unit of the recipient for many subcarriers. For example, one particular method consists in the introduction of characters feedback separability type of thinning. As another example, another specific method consisting in the use of the probing signal separability type of thinning. After station BS will transmit this message to the recipient communication unit, the communication unit of the addressee receives it, generates a channel signal according to a specific method and transmits this channel signal station BS, ensuring its channel information for multiple subcarriers. Station BS receives channel signal from the communication unit of the recipient, formed in accordance with a specific method, and may then determine channel estimates for the multiple subcarriers based on the received channel signal, as described above.

Also note that the command sensing line UL can be configured for multiple blocks of communication destinations, and this message instructs each set of blocks of communication recipients simultaneously transmit channel signal. When station BS receives multiple channel signals, it can then determine the channel estimates for each set of blocks of communication recipients, as described earlier.

The above example include the methodology of effective feedback according to present the invention in a communication system, some project specifications IEEE 802.16e/D5, may be modified for the following features or combinations thereof:

- In the above table, you can add the indicator which determines whether the feedback signals transmitted by the multiple antennas of the stations SS, to be one and the same symbol interval of the feedback (and vary by station BS using the shared symbolic evaluation/processing receiver type SDMA) or to take different symbols feedback (where the train station BS can decode them without causing mutual interference). If the feedback signals transmitted by the antennas SS should have a different character feedback, then the specific character of the feedback, which will take station antenna SS, will be determined by the value of the index is the cyclic time shift for this antenna station SS in the team IE sensing.

- In the above table, you can add the indicator which determines whether the channel coefficients to be transmitted symbol (symbols) feedback with or without coding with phase shift in the previous equations. If the channel coefficients must be transmitted in the symbol (symbols) feedback without coding with phase shift, then the channel coefficients of the feedback for each station BS, each antenna station SS and given subcarrier is transmitted separately the and combination of subcarriers and symbol intervals feedback. In the above table may be added another indicator that indicates that the Mb channel coefficients for a given antenna station SS is transmitted to a specific character interval feedback Mb coefficients for each of the Mb antenna station BS for the specified antenna station SS on Mb consecutive subcarriers in a given symbol interval feedback. In this case, the indicator of the previous paragraph may specify, are symbols of feedback for different stations SS the same (using station BS processing associated with the reception of type SDMA) or different character spacing feedback.

- It is important to note that the type of razdelimosti (cyclic or by thinning), used in sounding the symbol should not be used in one or more subsequent symbols feedback. To implement the strategy effective feedback according to the present invention the probe symbol used just to allow station BS can estimate the channel characteristic line UL, so you can decode the feedback signals transmitted in successive symbol intervals feedback. You can use any combination of the coding methodology for probing signals with the methodology of encoding feedback signals.

On Fig shows a device 800 for transmitting channel information. As shown, the device 800 comprises a receiver 801, circuit 803 channel evaluation circuit 805 of the channel signal and the transmitter 807. Schema 801 receiver is provided for receiving the signal from the communication unit source containing multiple subcarriers. Schema channel estimation define a set of channel estimates for a set of subcarriers received from the communication unit of the source, and circuit 805 of the channel signal to generate a channel signal based on the multiple channel estimates. Then the channel signal is transmitted to the communication unit source to provide communication unit source channel information.

Figure 9 presents a flowchart illustrating the operation of the device 800. In particular, figure 9 shows the steps necessary for the recipient communication unit for transmission to the communication unit source of information about the channel (for example, on the channel downlink). As described above, the channel contains a number of subcarriers. Logical flowchart begins with step 901, in which the reception signal (for example, when downlink). In step 903 is determined by the set of channel estimates for this signal. In particular, for each subcarrier of the received signal to determine at least one channel estimate. In step 905 create channel signal. As described above, the channel signal is based on the multiple channel estimates. Finally, on the Agay 907 channel signal is transmitted to the communication unit for sending information about the channel downlink.

Figure 10 shows a device 1000 for receiving a channel estimate (e.g., channel estimates downlink). As shown, the device 1000 includes a transmitter/receiver 1001, circuit 1003 evaluation channels and circuits 1005 recovery of the channel signal. Circuit 1001 of the transmitter/receiver is used for receiving a signal containing channel signal, and in addition use to send the message that specifies one of many possible ways, which will need to be used for formation of the channel signal.

As described above, the channel signal contains a set of channel estimates, and multiple channel estimates includes at least one channel estimate for each of the multiple subcarriers. Circuit 1003 estimates are provided for the evaluation of the receiving channel (e.g. channel uplink communication) for the received signal. Finally, the circuit 1005 recovery channel signal is provided to recover estimates of the multiple channel estimates on the basis of signal uplink communication based on the received signal and the estimated reception channel.

Figure 11 presents a flowchart illustrating the operation of the device 1000. The logical sequence of operations begins with step 1101, where the signal is received uplink communications (for example, the signal rising lineolate). As described above, the signal of the uplink communication channel contains the signal and the channel signal has multiple channel estimates (e.g., channel estimation downlink), and the set of channel estimates comprises at least one channel estimate for each of the multiple subcarriers. In step 1103 circuits 1003 estimates generated channel estimate for a channel uplink communication. In particular, to recover information from the signal of the uplink communication channel must be properly assessed. As soon as the channel is evaluated, from the signal of the uplink connection can be restored information. Thus, in step 1105 circuit 1005 restore channel estimation downlink signal uplink communication by restoring the channel signal embedded in the signal uplink communication and evaluate (for example, perform the reverse process to the encoding process of the channel signal, if necessary) channel estimation from the channel signal. As it is obvious to experts in the art, channel estimation can be used to help communication unit source to adapt the characteristics of the subsequent transmission to the communication unit of the recipient. Examples include, but not limited to, the definition and application of weights peridically beam forming transmission or a transmission with multiple inputs and multiple outputs (MIMO), execution planning with frequency selectivity, the choice of bands, the choice of modulation method and the coding rate, and so on

It should be noted that the above discussion provides a way to efficiently provide channel information to the transmitter for use in a closed-loop transmission. Mobile station encodes multiple broadband channels for transmission in one or more OFDM symbols. Many mobile stations transmit their feedback data simultaneously, and the base station uses its antenna grid for data sharing feedback from many users. It should be noted that as used above equations are given as examples of various embodiments of the invention. Specialists in the art it is obvious that they may be replaced by other equations, if they are not beyond being and scope of the invention. In addition, specialists in the art it should be clear that you can perform many various modifications, changes and offer many combinations in relation to the above options, without going beyond being and scope of the invention, and such modifications, changes and combinations should be considered within the boundaries of the concept of the invention. It is assumed that these modes the classification, modifications and combinations are included in the scope the following claims.

1. A method of transferring communication unit of the recipient to the communication unit source of information about the channel containing multiple subcarriers, and the method includes:

defining a set of channel estimates for a set of subcarriers received from the communication unit source;

the creation of the channel signal based on the multiple channel estimates; and

transmitting information about the channel by transmitting a channel signal in the communication unit source

moreover, the channel signal is based on at least one of:

;

;

; and

;

where Hu,m,l(k) channel estimation between the transmitter antenna with index 1 of the communication unit of the source and receiving antenna index m in the communication unit of the recipient for the subcarrier with index k; Hu,l(k) channel estimation between the transmitter antenna with index 1 of the communication unit of the source and receiving antenna in the communication unit of the recipient for the subcarrier with index k; δ(n) is equal to unity if n is zero, and zero otherwise; βu- scale factor; qu(k), qu,m(k) and su(k) - well-known sequence; Mm,u- the number of receiving antennas is in the communication unit of the destination; αu- shear factor; and Mb- the number of transmitting antennas in the communication unit of the source.

2. The method according to claim 1, in which the channel signal contains a combination of multiple channel estimates.

3. The method according to claim 1, additionally containing transmission channel sounding signal in the communication unit of the recipient together with a channel signal.

4. The method of obtaining channel estimates, containing the steps:

the signal containing the channel signal having the set of channel estimates, and a lot of channel estimates comprises at least one channel estimate for each of the multiple subcarriers;

evaluation of the receive channel for the received signal; and

restoration estimates from a set of channel estimates based on the received signal and the estimated reception channel.

5. The method according to claim 4, further containing:

receiving a pilot signal; and

the assessment of the receive channel contains the assessment of the receive channel based on a received pilot signal.

6. The way the channel estimates, containing:

receipt of the message, and the message indicates at least a specific method to be used to provide channel estimates from the communication unit of the recipient for many subcarriers;

the formation of the channel signal in accordance with the specific STRs is obom to provide channel estimates for the multiple subcarriers; and

the transmission channel signal to help the communication unit source in determining channel estimates for the multiple subcarriers.

7. The method according to claim 6, in which the channel signal contains at least one of:

the probing signal; and

the multiple channel estimates for multiple subcarriers.

8. The method of obtaining channel estimates in the communication unit of the source, and the method includes:

configuring messages for the communication unit of the recipient, and the message indicates at least a specific method to be used to obtain channel estimates from the communication unit of the recipient for many subcarriers;

send a message to the communication unit of the recipient;

the reception channel signal from the communication unit of the recipient, where the channel signal is formed in accordance with the specific way; and

determining channel estimates for the multiple subcarriers based on the received channel signal.

9. The method according to claim 8, in which the channel signal contains at least one of:

the probing signal; and

the multiple channel estimates for multiple subcarriers.

10. Device transmit channel information, and the device includes:

receiver for receiving the signal from the communication unit source containing multiple subcarriers;

schema channel on Enki to determine the multiple channel estimates for multiple subcarriers received from the communication unit source;

schematic of the channel signal to generate the channel signal based on the multiple channel estimates; and

transmission schemes for transmitting the channel signal in the communication unit of the source, to ensure the communication unit source channel information

when the channel signal is based on at least one of:

;

;

; and

;

where Hu,m,lchannel estimation between the transmitter antenna with index 1 of the communication unit of the source and receiving antenna index m in the communication unit of the recipient for the subcarrier with index k; Hu,l(k) channel estimation between the transmitter antenna with index 1 of the communication unit of the source and receiving antenna in the communication unit of the recipient for the subcarrier with index k; δ(n) is equal to unity if n is zero, and zero otherwise; βu- scale factor; qu(k), qu,m(k) and su(k) - well-known sequence; Mm,u- the number of receiving antennas in the communication unit of the recipient; αu- shear factor; and Mb- the number of transmitting antennas in the communication unit of the source.



 

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EFFECT: improvement of signal ratio to interference and noise.

22 cl, 4 dwg

FIELD: physics, communication.

SUBSTANCE: inventions are related to communication for provision of support of service soft-handoff (SSH) in system of "МДОЧР" with frequency hopping. Every sector simultaneously supports users in mode "without SSH" and users in "SSH" mode. User in mode "without SSH" connects only with one sector, and user in SSH mode simultaneously connects to multiple sectors. Users in mode "without SSH" are provided with traffic channels by their single sectors, and users in SSH mode are provided with traffic channels by their "servicing" sectors. For every sector traffic channels assigned for users in mode "without SSH" are orthogonal to each other and may be or may not be orthogonal to traffic channels assigned to users in SSH mode. Every sector processes accepted signal and restores transfers of data from users in mode "without SSH" of this sector. Every sector than evaluates interference that corresponds to users in mode "without SSH", and removes interference from accepted signal. Every sector additionally processes its signal with removed interference for restoration of data transfers from users in SSH mode.

EFFECT: provision of noises suppression during transfer.

22 cl, 10 dwg

FIELD: communications.

SUBSTANCE: method and device for transmission of upstream communication line acknowledgement information (ACK) in communication system which uses multiple access scheme with orthogonal frequency division multiplexing (OFDMA) includes data bit receiving for upstream communication line ACK; output of code words corresponding to data bit; modulation execution by quadrature phase shift keying (QPSK) on characters for ACK vector indices matching to code words for received data bit; execution of inverse fast Fourier (IFFT) on transmission signal containing subcarrier groups to which modulated transmission characters are assigned; and transmission of processed by IFFT transmission signal.

EFFECT: reliability enhancement for transmission of upstream communication line acknowledgement information (ACK) and reduction of service protocol data portion.

49 cl, 8 dwg

FIELD: communications.

SUBSTANCE: method includes stages in which OFDM characters are transmitted in such a way that data character size of particular OFDM character in each frame is set smaller than data character size of typical OFDM character within mentioned frame, OFDM characters are received and correlation factors are correspondingly calculated for this particular OFDM character on the basis of both corresponding data characters time-slot and data characters time-slot of typical OFDM character, phases of corresponding correlation factor are selected respectively which factor is calculated according to mentioned particular OFDM character, decimal part of frequency shift is evaluated and integer part of frequency shift is determined which part matches to decimal part of frequency shift thereby evaluating full frequency shift and achieving frequency synchronisation.

EFFECT: providing possibility to obtain precise initial frequency shift.

24 cl, 12 dwg, 1 tbl

FIELD: physics, communications.

SUBSTANCE: invention concerns mobile communication system using OFDM system. In a wireless broadband communication system using OFDM/OFDMA circuit, upline time sinchronisation between BS and SS and BS receiving signal intensity are set, and frequency band adjustment signal is transmitted from SS to BS so that SS would issue a frequency band query to BS.

EFFECT: minimised mutual jamming of frequency ban adjustment signal and data signal.

29 cl, 13 dwg

FIELD: physics.

SUBSTANCE: invention is related to device and method of channel assessment in communications system with OFDM. Device and method of channel assessment with application of signals of preambles received from servicing Unit B and neighboring Units B, each having N(>1) of transmitting antennae, in UE, which has M(>1) of receiving antennae, in wide-range system of wireless communication. Unit of calculation of Units B number calculates maximum number N of channel-assessed Units B, using preambles length, number of antennae in every Unit B and number of paths of multiradiate distribution. Generator of matrixes of preambles of cells multiplicity generates matrix x of preambles of cells multiplicity by generating of matrix of Unit B preambles for every of Units B and selection of matrixes of N preambles of Units B in accordance with capacity of reception among matrixes of Units B preambles. Facility of channel assessment performs channel assessment, using x and signals received through M of antennae for the period of preambles reception.

EFFECT: accurate channel assessment by ruling out intercellular interference in communications system MIMO.

28 cl, 20 dwg

FIELD: communications.

SUBSTANCE: invention pertains to communication technology and can be used in multiplexing schemes with orthogonal frequency division of signals. The system consists of base stations, located near each other. Sub-carrier, identification BS are transmitted, which are series for identifying base stations in a frequency range of the pilot symbol. Sub-carrier PAPR are transmitted (ratio of the peak to the average power), which are a series for reducing the PAPR pilot symbol, together with transmission of sub-carrier, identification BS in a frequency range.

EFFECT: increased number of identified base stations in the system.

49 cl, 11 dwg, 28 tbl

FIELD: communication systems.

SUBSTANCE: method of formation of preamble sequence that identifies every one of multiple mobile abonent stations located within the limits of cell or sector of communication system, which includes multiple subchannels that are assigned to mobile abonent stations, every one of subchannels includes multiple resolution cells, every one of which includes n adjacent subcarriers in frequency area, preamble sequence is transmitted prior to transmission of every channel, at that method includes formation of preamble sequence by means of phase shift of predetermined sequence according to predetermined sequence of phase shifts in frequency area.

EFFECT: formation of separate preamble sequences to spatial channels that are different from each other.

31 cl, 9 dwg

FIELD: physics.

SUBSTANCE: said utility invention relates to a system and a method for transmitting control information in a mobile communication system. The uplink control information transmission method in a communication system using the orthogonal frequency division multiple access (OFDMA) method is based on the following: the mobile station (MS) selects the target binding base station (BS), which the MS intends to establish communication with, and transmits a code combination assigned to the selected target binding BS, to the current binding BS through a fast uplink channel; after the code combination is received, the fast uplink channel assignment information for the selected BS, corresponding to the code combination received, is transmitted to the MS via the binding BS, the MS switches to the new binding BS corresponding to the fast uplink channel assignment information.

EFFECT: fast cell handover in communication system and transmission of various control information.

59 cl, 7 dwg, 2 tbl

FIELD: methods for processing data for distribution during transmission in multi-antenna communication system.

SUBSTANCE: for spatial distribution in multi-antenna OFDM system the transmitter conducts encoding, interleaving and indication of symbols for traffic data to produce data symbols, the transmitter processes each pair of data symbols to produce two pairs of transmitted symbols for transmission through a pair of antennas either (1) in two periods of OFDM symbol for spatial-temporal distribution during transmission, or (2) in two sub-ranges for spatial-temporal distribution during transmission. For data transmission, NT(NT-1)/2 various pairs of antennas are used, where various pairs of antennas are used for adjacent sub-ranges, where NT represents the number of antennas, the system may maintain a set of sizes of OFDM symbols, for various sizes of OFDM symbols, identical circuits are used for encoding, interleaving and modulation to facilitate processing in transmitter and receiver, the transmitter performs OFDM modulation for the stream of transferred symbols for each antenna according to selected size of OFDM symbol, the receiver conducts complementary processing.

EFFECT: ensured spatial distribution.

8 cl, 11 dwg

FIELD: physics, communication.

SUBSTANCE: invention is related to systems of wireless communication. Method and system for distribution of data bursts in system of wireless communication with availability of frame installed along symbol interval axis and frequency band axis, frame includes the first area, in which MAP-message is transmitted, and the second area, to which data bursts are distributed, the third area on the basis of symbol interval and frequency band is located in the second area, data bursts are serially distributed to the third area from the first interval of symbol along axis of frequency band.

EFFECT: provision of efficient distribution of data bursts in system of wireless communication.

14 cl, 2 dwg

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