Method and apparatus for determining the spatial channels in an spatial division multiple access (SDMA)-based wireless communication system

Method and device for determining spatial channel in wireless communication system based on spatial division multiple access (SDMA)

The following describes a large system about a communication system, and more specifically, about a method and device for determining a spatial channel in a wireless communication system based on Space Division Multiple Access (SDMA).

This patent application claims the title "Method and device for determining spatial channels in SDMA-based wireless communication systems (METHOD AND APPARATUS FOR DETERMINING THE SPATIAL CHANNELS IN A SDMA BASED WIRELESS COMMUNICATION SYSTEM)" filed on August 20, 2008. Provisional Application No. 61/090,501 and the application on May 21, 2008 entitled "Method and Apparatus for Determining Spatial Channels in SDMA-based Wireless Communication Systems (METHOD AND APPARATUS FOR DETERMINING THE SPATIAL CHANNELS IN A SDMA BASED) WIRELESS COMMUNICATION SYSTEM)" provisional application No. 61/055,012, which has been assigned to its assignee and is expressly incorporated herein by reference.

In order to deal with the problem of increasing bandwidth requirements for wireless communication systems, different mechanisms are being developed to allow multiple user terminals to communicate with a single access point by sharing channel resources while achieving high data throughput. Multiple-input multiple-output (MIMO) technology represents a method that has recently emerged as a popular technology for next-generation communication systems. MIMO technology has been adopted in several emerging wireless communication standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. IEEE 802.11 refers to a set of wireless local area network (WLAN) air interface (air link media) standards developed by the IEEE 802.11 committee for short-range communications (for example, tens of meters to hundreds of meters).

In wireless communication systems, the medium access control (MAC) protocol is designed to take advantage of the degrees of freedom provided by the air link medium. The most commonly used degrees of freedom are time and frequency. For example, in the IEEE 802.11 MAC protocol, the time freedom is utilized through the Carrier Sense Multiple Access (CSMA) protocol. The CSMA protocol attempts to ensure that no more than one transmission occurs in a neighborhood with potentially high interference. The frequency freedom can be utilized by using different channels.

Recent developments have led to space size becoming a viable option. SDMA can be used to improve the utilization of air link media by scheduling multiple terminals for simultaneous transmission and reception. Use the spatial stream to send data to each of the terminals. For example, in the case of using SDMA, the transmitter forms a transmission stream ("transmission stream") orthogonal to the individual receivers. Because the transmitter has several antennas and the transmission/reception channel consists of several paths, such positive communication can be formed. The receiver may also have one or more antennas (such as in a single input multiple output (SIMO) or MIMO receiver). For this example, assume that the transmitter is an access point (AP) and the receiver is a station (STA). The flow-through is formed so that a flow that is targeted at, for example, station 1 (STA-1) is treated as low-power interference at station 2 (STA-2) and station 3 (STA-3). In order to form a positive communication, the AP needs to have channel status information (CSI) from each of the receiving STAs. CSI can be measured and communicated in several ways. What is disclosed is a description of the effective request, collection, and calculation of the channel status information of the spatial stream. The various described aspects can be used for very high throughput (VHT) transmission in wireless networks.

Therefore, one or more of the deficiencies described above will need to be addressed.

According to various aspects, the present invention relates to a system and/or method for determining a spatial channel in a wireless communication system based on spatial division multiple access (SDMA).

In one aspect, a device for communicating with a plurality of nodes is disclosed. The device includes: a processing system configured to calculate a precoding matrix that defines a spatial stream; and a transceiver configured to transmit data to a node on the spatial stream.

In another aspect, a method for communicating with a plurality of nodes includes: calculating a precoding matrix that defines a spatial stream; and transmitting data to the node on the spatial stream through a transceiver.

In another aspect, a device for communicating with a plurality of nodes includes: a component for calculating a precoding matrix that defines a spatial stream; and a device for transmitting data to the node on the spatial stream through a transceiver member.

In yet another aspect, a computer program product for communication includes a machine-readable medium encoded with instructions that can be executed to: calculate a precoding matrix that defines a spatial stream; and transmit data to a node on the spatial stream .

In yet another aspect, an access point includes: a wireless network adapter configured to support no-load transmission connection for peer nodes to the network; a processing system configured to calculate a defined space The precoding matrix of the stream; and the transceiver, which is configured to transmit data to the node on the spatial stream.

These and other sample aspects of the present invention will be described in the following detailed description and in the accompanying drawings.

Hereinafter, various aspects of the present invention will be described more fully with reference to the accompanying drawings. However, the present invention can be embodied in many different forms and should not be construed as being limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be comprehensive and complete, and will fully convey the scope of the invention to those skilled in the art. Based on the teachings herein, those familiar with the art should understand that the scope of the present invention is intended to cover any aspect of the present invention disclosed herein, regardless of whether it is implemented independently of any other aspect of the present invention or related to the present invention. Any other aspects of the invention can be combined and implemented. For example, any number of aspects described herein can be used to implement a device or practice a method. In addition, the scope of the present invention is intended to cover the use of other structures, functions, or structures and functions other than the various aspects of the present invention described herein or different from the various aspects of the present invention described herein. This device or method. It should be understood that any aspect of the invention disclosed herein can be embodied by one or more elements within the scope of the patent application.

Now referring to FIG. 1, several aspects of the wireless network will be presented. A wireless network 100 is shown. The wireless network 100 has a number of wireless nodes denoted as nodes 110 and 120 as a whole. Each wireless node can receive and/or transmit. In the following detailed description, for downlink communication, the term "access point" is used to indicate a transmitting node and the term "access terminal" is used to indicate a receiving node, and for uplink communication, the term " "Access point" is used to refer to the receiving node and the term "access terminal" is used to refer to the transmitting node. However, those familiar with the technology should be easy to understand that other terms or names can be used for the access point and/or the access terminal. For example, an access point may be referred to as a base station, a base transceiver station, a station, a terminal, a node, an access terminal acting as an access point, or some other suitable term. The access terminal can be referred to as a user terminal, mobile station, user station, station, wireless device, terminal, node, or some other suitable terminology. The various concepts described throughout this disclosure are intended to be applied to all suitable wireless nodes regardless of their specific names.

The wireless network 100 can support any number of access points allocated throughout the geographic area used to provide coverage to the access terminal 120. The system controller 130 can be used to provide coordination and control of access points, and access to other networks (for example, the Internet) of the access terminal 120. For simplicity, an access point 110 is shown. An access point is usually a fixed terminal that provides an airborne transmission service to an access terminal in a covered geographic area. However, in some applications, the access point may be mobile. Access terminals (which can be fixed or mobile) use the no-load transmission service of the access point or engage in peer-to-peer communication with other access terminals. Examples of access terminals include telephones (e.g. cellular phones), laptop computers, desktop computers, personal digital assistants (PDAs), digital audio players (e.g. MP3 players), cameras, game consoles , Or any other suitable wireless node.

The wireless network 100 can support MIMO technology. By using MIMO technology, the access point 110 can use SDMA to communicate with multiple access terminals 120 at the same time. SDMA is a multi-access mechanism that enables multiple streams transmitted to different receivers at the same time to share the same frequency channel and thus provide a larger user capacity. This is achieved by spatially encoding each data stream and then transmitting each spatially encoded stream on the downlink via a different transmission antenna. The spatially coded data stream arrives at the access terminals with different spatial signatures, which enables each access terminal 120 to recover the data stream to the other access terminal 120. On the uplink, each access terminal 120 transmits a spatially coded data stream, which enables the access point 110 to identify the source of each spatially coded data stream.

One or more access terminals 120 may be equipped with multiple antennas to enable specific functionality. With this configuration, the multiple antennas at the access point 110 can be used to communicate with the multi-antenna access point to improve the data throughput without additional bandwidth or transmission power. This can be achieved by splitting the high data rate signal at the transmitter into multiple lower rate data streams with different spatial signatures, thus enabling the receiver to separate these streams into multiple channels and appropriately combine these streams to Achieved by recovering high-speed data signals.

Although the following disclosure will describe an access terminal that also supports MIMO technology, the access point 110 can also be configured to support an access terminal that does not support MIMO technology. This method allows older versions of the access terminal (ie, the "old version" terminal) to still be deployed in the wireless network, thereby extending its useful life, while allowing the introduction of newer MIMO access terminals when appropriate .

In the following detailed description, various aspects will be described with reference to a MIMO system supporting any suitable wireless technology, such as Orthogonal Frequency Division Multiplexing (OFDM). OFDM is a spread spectrum technology that distributes data among a large number of subcarriers spaced at precise frequencies. The gap provides the "orthogonality" that enables the receiver to recover data from the subcarriers. The OFDM system can implement IEEE 802.11 or some other air interface standard. For example, other suitable wireless technologies include Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), or any other suitable wireless technology, or any combination of suitable wireless technologies. The CDMA system can implement IS-2000, IS-95, IS-856, Wideband CDMA (WCDMA) or some other suitable air interface standard. The TDMA system can implement the Global System for Mobile Communications (GSM) or some other suitable air interface standard. Those familiar with the technology should easily understand that the various aspects of the present invention are not limited to any specific wireless technology and/or air interface standard.

The wireless node (whether it is an access point or an access terminal) can be implemented by using the protocol of a layered structure. The layered structure includes the physical (PHY) layer, which implements all physical and motor specifications to integrate wireless The node interfaces to the shared wireless channel; the MAC layer, which coordinates access to the shared wireless channel; and the application layer, which performs various data processing functions, including, for example, voice and multimedia codecs and graphics processing. Additional protocol layers (eg, network layer, transport layer) can be required for any specific application. In some configurations, a wireless node can act as a relay point between an access point and an access terminal or between two access terminals, and therefore may not require an application layer. Those familiar with this technology will easily be able to implement appropriate protocols for any wireless node depending on the specific application and the overall design constraints imposed on the entire system.

When the wireless node is in the transmission mode, the application layer processes the data, segments the data into packets, and provides the data packets to the MAC layer. When the MAC layer decides to transmit, it provides the MAC packet block to the PHY layer. The PHY layer assembles PHY packets by combining blocks of MAC packets into payloads and adding pre-terms. As will be discussed in more detail later, the PHY layer is also responsible for providing various signal processing functions (for example, modulation, coding, spatial processing, etc.). The preamble (which is sometimes referred to as the physical layer aggregation protocol (PLCP)) is used by the receiving node to detect the beginning of the PHY packet and to synchronize with the node data clock of the transmitter. The preamble contains training signals that can be used to assist in improving the guidance of the stream transmitted by the antenna. Training signals are also called pilot signals or sounding signals. PHY packets are sometimes referred to as physical layer protocol data units (PLPDUs), but they can also be referred to as frames, packets, slots, fragments, or any other suitable names.

When the wireless node is in the receiving mode, the process is reversed. That is, the PHY layer detects incoming PHY packets from the wireless channel. The preamble allows the PHY layer to lock the PHY packet and perform various signal processing functions (for example, demodulation, decoding, spatial processing, etc.). Once processed, the PHY layer restores the MAC packet block carried in the payload of the PHY packet and provides the MAC packet to the MAC layer.

Figure 2 is a conceptual block diagram illustrating an example of the signal processing function of the PHY layer. In the transmission mode, the TX data processor 202 can be used to receive data from the MAC layer and encode (eg, turbo-encode) the data to facilitate forward error correction (FEC) at the receiving node. The encoding process results in a sequence of code symbols, which can be grouped together in blocks by the TX data processor 202 and mapped to signal clusters to generate a sequence of modulation symbols.

In a wireless node implementing OFDM, the modulation symbols from the TX data processor 202 can be provided to the OFDM modulator 204. The OFDM modulator splits the modulated symbols into parallel streams. Each stream is then mapped to OFDM subcarriers and then combined together using Inverse Fast Fourier Transform (IFFT) to generate a time-domain OFDM stream.

The TX spatial processor 205 performs spatial processing on the OFDM stream. This can be achieved by spatially precoding each OFDM and then providing each spatially precoded stream to a different antenna 208 via the transceiver 206. Each transceiver 206 modulates the RF carrier with a respective precoded stream for transmission on the wireless channel.

In the receiving mode, each transceiver 206 receives signals via its respective antenna 208. Each transceiver 206 can be used to recover the information modulated onto the RF carrier and provide the information to the RX spatial processor 210.

The RX spatial processor 210 performs spatial processing on the information to recover any spatial flow to the wireless node 200. The spatial processing may be performed according to channel correlation matrix inversion (CCMI), minimum mean square error (MMSE), soft interference cancellation (SIC), or some other suitable technique. If multiple spatial streams go to the wireless node 200, the spatial streams can be combined by the RX spatial processor 210.

In the wireless node implementing OFDM, the stream from the RX spatial processor 210 (or the combined stream) is provided to the OFDM demodulator 212. The OFDM demodulator 212 uses Fast Fourier Transform (FFT) to convert the stream (or combined stream) from the time domain to the frequency domain. The frequency domain signal includes a separate stream for each subcarrier of the OFDM signal. The OFDM demodulator 212 recovers the data carried on each subcarrier (that is, the modulation symbol) and multiplexes the data into a modulation symbol stream.

The RX data processor 214 can be used to translate the modulation symbols back to the correct point in the signal cluster. Due to noise and other interference in the wireless channel, the modulation symbol may not correspond to the exact location of the point in the original signal cluster. The RX data processor 214 detects which modulated symbol is most likely to be transmitted by finding the minimum distance between the received point and the position of the valid symbol in the signal cluster. For example, in the case of turbo codes, these soft decisions can be used to calculate the log-likelihood ratio (LLR) of the code symbols associated with a given modulation symbol. Next, the RX data processor 214 uses the code symbol LLR sequence to decode the data originally transmitted before the data is provided to the MAC layer.

The wireless node 200 also includes a packetizer 220. During the transmission operation, the data is fed to the packetizer 220. Specifically, the packetizer 220 operates to receive data from the MAC layer and create a packet of appropriate size and format to be transmitted.

The precoder 218 uses the precoding matrix to process the output of the packetizer 220 before sending it to the TX data processor 202, which itself sends the output to the TX space after the output is processed by the OFDM modulator 204 Before the processor 205. As described herein, the precoder 218 utilizes a precoding matrix to encode data from the packetizer 220 to compensate for spatial channel conditions.

In the receiving operation, after the data received by the spatial RX processor 210 has been processed by the OFDM demodulator 212, the data is sent to the RX data processor 214. The data received and processed by the RX spatial processor 210 is forwarded to the precoding matrix calculator 216. The result of the precoding matrix calculator 216 is fed to the precoder 218.

Referring to FIG. 3, and further referring to FIG. 4, a timing diagram 300 and a flowchart 400 will be used to describe the operation of the wireless node 200, where the wireless node is the access point 2, and the access point 2 optimizes its transmission guide The ability to lead to multiple receivers. In this example, SDMA is used from the access point (AP) STA-A 302a to multiple responder stations STA-B 302b, STA-C 302c to STA-X 302x. In order to optimize navigation, the access point STA-A 302a needs channel status information (CSI) from each of the responder stations STA-B 302b to STA-X 302x.

In one method, as explained in step 402, in order to obtain the CSI, the access point STA-A 302a sends a training request (TRQ) message 350 to the responder stations STA-B 302b to STA-X 302x. As shown in Figure 3, the TRQ message 350 can be unicast to each responding station or broadcast to all stations STA-B 302b to STA-X 302x. The TRQ message 350 may contain the following information: the scheduled time of the training signal from each of the responder stations STA-B 302b to STA-X 302x, or identification from the responder stations STA-B 302b to STA-X 302x The unique identifier or method of the training signal received by each of them.

It should be noted that the scheduling time of the training signal can be implicit or explicit. An example of implicit training scheduling is for the responder station to schedule the transmission of the training signal for a fixed duration after receiving the TRQ message 350. Another method is to enable the responder station to transmit the training signal in an interleaved manner with a fixed delay between transmissions of consecutive responder stations. The order in which the responder station will send training signals can be specified by the TRQ message 350. The access point STA-A 302a may also only request the time when each of the responder stations must send its training signal. Various ways to indicate the time of response are available. For example, the bits in the TRQ message 350 may indicate the time at which the responder stations STA-B 302b to STA-X 302x will respond after a certain amount of time.

The access point STA-A 302a must also indicate the implicit or explicit method so that the training signal from each of the responder stations STA-B 302b to STA-X 302x can be distinguished. One method is to use the time of arrival of the training signal to identify the responding station. Another method is to make each responder station use a unique identifier based on the responder station or a unique training signal that can be specified by the TRQ message 350. The access point STA-A 302a can also send requests on the Orthogonal Frequency Division Multiple Access (OFDMA) sub-band. Several types of training signals can be constructed for training purposes. For example, in one method, a known training sequence that is scrambled with a unique receiving station identifier can be used. Another method can be to assign a unique Walsh cover code to each responder station. The unique identifier can be assigned to the responder station statically or dynamically. In addition, if the transmitted data can be received and decoded at the receiving access point STA-A 302a or the responding station, one of the responder stations STA-B 302b to STA-X 302x or the access point STA-A 302a can Burden the data transmission on the training request/signal.

3, in step 404, after broadcasting the TRQ message 350, each of the receiving stations STA-B 302b to STA-X 302x responds with a separate training signal 352b to 352x. The responder stations STA-B 302b to STA-X 302x will each be assigned an orthogonal code to allow the access point STA-A 302a to uniquely identify its respective training signals 352b to 352x. In one method, Walsh cover codes will be used. It is now possible to uniquely decode these returned training signals 352b to 352x by knowing these pre-assigned or implicitly inferred orthogonal codes.

In step 406, once the training signals 352b to 352x are received at the access point STA-A 302a, the access point STA-A 302a calculates for each responder station STA-B 302b to STA that has sent the training signal -CSI of X 302x. The CSI of each of the responder stations STA-B 302b to STA-X 302x is combined and used to calculate the precoding matrix. The precoding matrix defines the spatial stream to each of the responder stations STA-B 302b to STA-X 302x. In one aspect of the present disclosure, these spatial streams enable the data sent on the spatial stream of STA-B 302b to be received at the responder station STA-B 302b with a relatively high signal-to-noise ratio (SNR). But it will only appear at other responder stations as a low-noise signal. If the responder station (for example, responder station STA-B 302b) does not send a training signal (for example, due to the reception error of the TRQ message 350), the access point STA-A 302a can suppress the transmission of spatially multiplexed data The STA-B 302b may use the CSI obtained from the previous training request.

In step 408, one or more of the responder stations STA-B 302b to STA-X 302x transmits the TRQ message to the access point STA-A 302a. Once the access point receives the TRQ message, the operation proceeds to step 410.

In step 410, the access point STA-A 302a will send a training message in response to the TRQ message sent by one of the stations STA-B 302b to STA-X 302x.

In step 412, once the precoding matrix is calculated, the access point STA-A 302a can send the data to the responder station. The long training field (LTF), which can include pilots, sounding, or training sequences, precedes the precoded data. Then, each responder station can receive its data with high SNR due to the pre-coded transmission.

In some scenarios, multiple responder stations can transmit data to the access point STA-A 302a without any precoding. The access point STA-A 302a can decode data from individual responder stations by using the CSI collected during the training phase.

It should be noted that several transmission modes can be used at the access point STA-A 302a for requesting training messages from the responder station. The access point STA-A 302a can send TRQ messages interleaved in time (TDMA). TRQ messages can be carried on the data transmission from the access point STA-A 302a to the responder station. In addition, the access point STA-A 302a can also use OFDMA to send TRQ messages to each of the responder stations. In addition, if the precoding matrix calculated in the previous exchange is still valid, the previously calculated precoding matrix can be used to send the TRQ message using SDMA.

Various methods of calculating the precoding matrix can be used, such as techniques well known in the art. For example, MMSE, forced zeroing, or single value decomposition can be used. Also, other terms used for the precoding matrix can be steering matrix, steering vector, and steering vector that can be derived from complete CSI. Alternatively, the receiver can provide CSI feedback by feeding back the steering vector from the codebook.

The TRQ message 350 may be a multi-client TRQ message. For example, an aggregate physical layer protocol data unit (APPDU) to multiple responder stations is used to send requests to multiple responder stations. In this method, TDMA is used to send training requests to multiple stations and the frame is sent to multiple stations in a single TDMA transmission.

In another method, by using OFDMA, the transmitting station uses SDMA to send training requests to multiple responding stations. Then, the responding station can respond with its training signal. By performing this process, the access point STA-A 302a calculates a precoding matrix for downlink SDMA transmission. After receiving the training information, the transmitting station transmits the data and the calculated precoding matrix. This will be used to make the response station use SDMA to transmit uplink data.

In addition to using SDMA for operation, OFDMA technology can also be used to transmit TRQ messages 350. In addition, use OFDMA to send back training information from various responder stations. This technique may be suitable for training more spatial streams than can be supported by an access point (such as STA-A 302a). By doing so, the access point STA-A 302a will maximize its options for optimized scheduling.

FIG. 5 is a functional block diagram of the signal processor 500 of the wireless node in the wireless communication network of FIG. 1. The signal processor 500 includes a calculator module 502 that calculates a precoding matrix defining a spatial stream. The signal processor 500 also includes a transmitter module 504 that transmits data to the node on a spatial stream through a transceiver.

It should be understood that any specific order or hierarchy of steps described in the content of the wireless node is presented to provide an example of the wireless node. Based on the design priority, it should be understood that the specific order or hierarchical structure of the steps can be rearranged while remaining within the scope of the present invention.

Various parts of the wireless node can be implemented by one or more general-purpose processors, digital signal processors (DSP), special application integrated circuits (ASIC), field programmable gate arrays (FPGA), programmable logic devices (PLD) ), other programmable logic components, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, controller, microcontroller, state machine, or any other circuit that can execute software. Software should be broadly interpreted as meaning commands, data, or any combination thereof, regardless of whether it is called software, firmware, middleware, microcode, hardware description language, or something else. The software may be stored on a machine-readable medium or embodied in one or more components such as DSP or ASIC. Machine-readable media may include various memory components, including, for example, RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM ( Erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), register, floppy disk, optical disk, hard disk drive or any other suitable storage medium, or any combination thereof. Machine-readable media may also include transmission lines, carrier waves modulated by data, and/or other components used to provide software to wireless nodes. The machine-readable medium can be embodied in a computer program product. The computer program product may include packaging materials.

Whether various aspects of precoding are implemented in hardware, software, or a combination thereof will depend on the specific application and the design constraints imposed on the entire system. Those skilled in the art can implement the described functionality in varying ways for each specific application, but these implementation decisions should not be construed as causing a departure from the scope of the present invention.

The previous description is provided so that anyone familiar with the art can fully understand the full scope of the present invention. For those familiar with this technology, the modifications to the various configurations disclosed in this article will be obvious. Therefore, the scope of the patent application is not intended to be limited to the various aspects of the present invention described herein, but conforms to all categories consistent with the language of the scope of the patent application. The reference to an element in the singular is not intended to mean "one and only "One" (unless specifically stated as such), but means "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. All structural equivalents and functional equivalents of the various aspects of the elements described throughout this disclosure that are generally known or later known to those skilled in the art are expressly incorporated herein by reference and It is intended to be covered by the scope of patent application. In addition, any content disclosed in this article is not intended to be exclusively used by the public, regardless of whether the disclosure content is clearly stated in the scope of the patent application. Unless the element in the scope of the patent application is explicitly stated using the phrase "component used for...", or in the case of a method claim, the element uses the phrase "used for... The steps" are described, otherwise the element will not be interpreted under the terms of paragraph 6 of 35 USC § 112.

<p>100. . . Wireless network</p><p>110. . . Access point</p><p>120. . . Access terminal</p><p>130. . . System controller</p><p>200. . . Wireless node</p><p>202. . . TX data processor</p><p>204. . . OFDM modulator</p><p>205. . . TX space processor</p><p>206. . . transceiver</p><p>208. . . antenna</p><p>210. . . RX space processor</p><p>212. . . OFDM demodulator</p><p>214. . . RX data processor</p><p>216. . . Precoding matrix calculator</p><p>218. . . Precoder</p><p>220. . . Packetizer</p><p>300. . . Timing diagram</p><p>302a. . . Access point STA-A</p><p>302b. . . Responder station STA-B</p><p>302c. . . Responder station STA-C</p><p>302x. . . Responder station STA-X</p><p>350. . . Training request (TRQ) message</p><p>352b. . . Training signal</p><p>352c. . . Training signal</p><p>352x. . . Training signal</p><p>500. . . Signal processor</p><p>502. . . Calculator module for calculating precoding matrix defining spatial stream</p><p>504. . . Transmitter module that transmits data to nodes on a spatial stream through a transceiver</p>

Figure 1 is a diagram of a wireless communication network;

2 is a block diagram of an example of various signal processing functions of the PHY layer of the wireless node in the wireless communication network of FIG. 1;

FIG. 3 is a sequence diagram illustrating the process of establishing guidance information that can be used in the wireless communication network of FIG. 1;

FIG. 4 is a flowchart of the operation of the guidance information establishment mode of the wireless communication network of FIG. 1; and

FIG. 5 is a functional block diagram of the signal processor of the wireless node in the wireless communication network of FIG. 1. FIG.

According to convention, some of the diagrams may be simplified for clarity. Therefore, the drawings may not depict all the components of a given apparatus (e.g., device) or method. Finally, similar reference numbers may be used throughout this specification and the figures to indicate similar features.