CN108882369B - Signal processing method, system, access point and mobile station - Google Patents

Abstract

The embodiment of the invention provides a signal processing method, a system, an access point and a mobile station, wherein the method comprises the following steps: acquiring measurement information corresponding to each transmission branch in a plurality of transmission branches deployed in a wide area; selecting a target transmission branch from the plurality of transmission branches based on the measurement information, wherein the number of the target transmission branches is within a first interval range; respectively adopting the target transmission branches to transmit configuration message frames to the mobile station; receiving a configuration response message frame which is returned by the mobile station and corresponds to the configuration message frame; and respectively adopting the target transmission branches to transmit data frames to the mobile station based on the configuration response message frame. The invention utilizes the multipath transmission branches distributed in a wide area to transmit the spatial fading uncorrelated signals, solves the deep fading problem of the short wave channel, improves the channel adaptability of the short wave system and further improves the communication performance.

Description

Signal processing method, system, access point and mobile station

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a signal processing method, a signal processing system, an access point, and a mobile station.

Background

The short-wave communication is a communication means which is not dependent on a fixed infrastructure which is easy to destroy, has the advantages of long communication distance, flexibility, convenience in networking and the like, and can provide important basic capability support for integrated cooperation of sea, land, air and sky. However, short-wave communication depends on unstable atmospheric ionospheric reflection, and short-wave channels have the characteristics of time-varying dispersion, fading, serious interference and the like. Meanwhile, with the continuous deterioration of the electromagnetic environment faced by the short wave frequency band and the communication requirement of the long-distance and high-dynamic battlefield environment, the improvement of the communication rate and the communication quality of the short wave communication is urgent.

The prior art proposes a scheme with multiple transmission branches, and uses 1 access point to serve a mobile station in the transmission direction from the access point to the mobile station, compared with the traditional single transmission and single reception scheme, the improvement point is to use 4 transmission branches, so as to improve the system performance through diversity transmission. However, since the long-distance short-wave communication adopts sky-wave communication based on an ionosphere reflection mechanism, when multiple transmission branches are arranged in the same access point, because the transmission branches are in the same area and are close to each other, fading independence of the multiple transmission branches cannot be guaranteed, and deep fading still occurs at the same time, so that the problem of communication performance of a short-wave system is difficult to solve.

Disclosure of Invention

In view of the above problems, embodiments of the present invention are proposed to provide a signal processing method and a corresponding signal processing system, an access point and a mobile station that overcome or at least partially solve the above problems.

In order to solve the above problem, an embodiment of the present invention discloses a signal processing method, which is applied to an access point side, and the method includes:

acquiring measurement information corresponding to each transmission branch in a plurality of transmission branches deployed in a wide area;

selecting a target transmission branch from the plurality of transmission branches based on the measurement information, wherein the number of the target transmission branches is within a first interval range;

respectively adopting the target transmission branches to transmit configuration message frames to the mobile station;

receiving a configuration response message frame which is returned by the mobile station and corresponds to the configuration message frame;

and respectively adopting the target transmission branches to transmit data frames to the mobile station based on the configuration response message frame.

The embodiment of the invention also discloses a signal processing method which is applied to the mobile station side, and the method comprises the following steps:

when handshake frames sent by a plurality of sending branches are received, measuring information corresponding to channels between the sending branches and the mobile station is respectively obtained, wherein the sending branches are wide-area deployed sending branches;

organizing the measurement information into a measurement information frame, and returning the measurement information frame to an access point;

receiving a configuration message frame sent by a plurality of target transmission branches, wherein the target transmission branches are transmission branches which are selected by an access point based on the measurement information frame and the number of which is within a first interval range from the plurality of transmission branches;

returning a corresponding configuration response message frame to the access point based on the configuration message frame;

and receiving the data frames transmitted by the target transmission branches.

The embodiment of the invention also discloses a signal processing system, which comprises an access point and a mobile station, and is characterized in that the access point comprises an indoor unit, a plurality of outdoor units deployed in a wide area, short wave antennas and a synchronous digital system optical ring network, wherein each outdoor unit is connected with one set of short wave antenna through a radio frequency feeder line, and the outdoor unit is connected to the indoor unit through the synchronous digital system optical ring network;

the indoor unit is used for selecting candidate outdoor units from the outdoor units, assembling handshake frames aiming at the candidate outdoor units, sending the handshake frames to the corresponding candidate outdoor units in a baseband signal mode, selecting target outdoor units from the outdoor units based on the measurement information frames after receiving the measurement information frames sent by the candidate outdoor units, assembling configuration information frames to be sent to the target outdoor units, and assembling data frames to be sent to the target outdoor units after receiving configuration response information frames sent by the target outdoor units;

the outdoor unit is used for sending the handshake frame to the mobile station in the form of short-wave frequency band radio frequency signals, sending the measurement information frame to the indoor unit when receiving the measurement information frame returned by the mobile station based on the handshake frame, sending the configuration message frame to the mobile station after receiving the configuration message frame sent by the indoor unit, sending the configuration response message frame to the indoor unit after receiving the configuration response message frame returned by the mobile station based on the configuration message frame, and sending the received data frame sent by the indoor unit to the mobile station;

the mobile station is used for measuring the channel between the candidate outdoor unit and the mobile station based on the handshake frame to obtain corresponding measurement information, assembling the measurement information into a measurement information frame and sending the measurement information frame to the candidate outdoor unit, returning a corresponding configuration response message frame to the target outdoor unit after receiving the configuration message frame sent by the target outdoor unit, and receiving the data frame sent by the target outdoor unit.

The embodiment of the invention also discloses an access point, which comprises:

the measurement information acquisition module is used for acquiring measurement information corresponding to each transmission branch in a plurality of transmission branches deployed in a wide area;

a target transmission branch selecting module, configured to select a target transmission branch from the multiple transmission branches based on the measurement information, where the number of the target transmission branches is within a first interval range;

a configuration message frame sending module, configured to send configuration message frames to the mobile station by using the target sending branches, respectively;

a configuration response message frame receiving module, configured to receive a configuration response message frame corresponding to the configuration message frame returned by the mobile station;

and a data frame sending module, configured to send data frames to the mobile station by using the target sending branches respectively based on the configuration response message frame.

The embodiment of the invention also discloses a mobile station, which comprises:

a measurement information obtaining module, configured to obtain measurement information corresponding to channels between a plurality of transmission branches and the mobile station when handshake frames sent by the transmission branches are received, where the transmission branches are wide-area deployed transmission branches;

a measurement information frame sending module, configured to organize the measurement information into a measurement information frame, and return the measurement information frame to an access point;

a configuration message frame receiving module, configured to receive a configuration message frame sent by a plurality of target sending branches, where the target sending branches are sending branches selected by an access point from the plurality of sending branches based on the measurement information frame and the number of the sending branches is within a first interval range;

a configuration response message frame sending module, configured to return a corresponding configuration response message frame to the access point based on the configuration message frame;

and the data frame receiving module is used for receiving the data frames sent by the target sending branches.

The embodiment of the invention has the following advantages:

the embodiment of the invention provides a signal processing method based on short-wave wide-area diversity, which can solve the problem of poor permeability of a short-wave antenna transmission system based on ionosphere reflection, and utilizes multi-path transmission branches of wide-area distribution to transmit spatial fading uncorrelated signals to solve the deep fading problem of a short-wave channel, thereby improving the channel adaptability of a short-wave system and further improving the permeability.

Furthermore, the embodiment of the invention ensures that the frame lengths of the sending branches are the same by coordinating the frame lengths of the sending branches, thereby meeting the requirements of the relevant time of the sending branches; the pilot frequency length of each sending branch is ensured to be the same by coordinating the pilot frequency length when the multiple sending branches are transmitted, thereby meeting the pilot frequency signal quality requirement of each sending branch, reducing the interference among the branches and simplifying the signal processing of a receiver.

Drawings

FIG. 1 is a block diagram of a signal processing system according to an embodiment of the present invention;

FIG. 2 is a flow chart of the steps of one embodiment of a signal processing method of the present invention;

FIG. 3 is a schematic diagram of a windowing process according to an embodiment of a signal processing method of the present invention;

FIG. 4 is a measurement information frame diagram of an embodiment of a signal processing method of the present invention;

FIG. 5 is a diagram of a configuration message frame of an embodiment of a signal processing method of the present invention;

FIG. 6 is a diagram illustrating a frame structure of a configuration response message according to an embodiment of a signal processing method of the present invention;

FIG. 7 is a diagram of a data frame structure of an embodiment of a signal processing method according to the invention, which is shown in FIG. 1;

FIG. 8 is a diagram of a data frame structure of an embodiment of a signal processing method according to the present invention, which is shown in FIG. 2;

FIG. 9 is a flow chart of steps in another signal processing method embodiment of the present invention;

fig. 10 is a block diagram of an access point embodiment of the present invention;

fig. 11 is a block diagram of a mobile station embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Referring to fig. 1, a block diagram of an embodiment of a signal processing system of the present invention is shown, which may include an access point and a mobile station, and is applied to signal processing between the access point and the mobile station.

In the embodiment of the present invention, the access point may include but is not limited to: indoor unit, a plurality of outdoor units deployed in wide area, short wave antenna, SDH (Synchronous Digital Hierarchy) optical ring network. The SDH optical ring network provides a data transmission path for the indoor unit and the outdoor unit and provides a timing function for the outdoor unit; each outdoor unit can be connected with a set of short wave antenna through a radio frequency feeder line, each outdoor unit can be connected to the indoor unit through an SDH optical ring network by adopting optical fibers, and each outdoor unit can communicate with the mobile station through the short wave antenna.

In one implementation, the spacing between the outdoor units may preferably be not less than 100 km.

In the embodiment of the invention, the signal interacted between the indoor unit and the outdoor unit is a baseband signal, the signal interacted between the outdoor unit and the mobile station is a short-wave radio frequency signal, and the outdoor unit is used for converting the baseband signal sent by the indoor unit into the short-wave radio frequency signal to be forwarded to the mobile station and converting the short-wave radio frequency signal sent by the mobile station into the baseband signal to be sent to the indoor unit.

In a preferred embodiment of the present invention, the indoor unit may be configured to:

selecting candidate outdoor units from the plurality of outdoor units;

assembling handshake frames for the candidate outdoor units, and transmitting the handshake frames to the corresponding candidate outdoor units in the form of baseband signals;

after receiving the measurement information frame sent by the candidate outdoor unit, selecting a target outdoor unit from the plurality of outdoor units based on the measurement information frame;

assembling a configuration message frame and sending the assembled configuration message frame to a target outdoor unit;

and after receiving the configuration response message frame sent by the target outdoor unit, assembling the data frame and sending the data frame to the target outdoor unit.

The outdoor unit may be configured to:

transmitting the handshake frame to a mobile station in the form of a short-wave frequency band radio frequency signal;

when receiving a measurement information frame returned by the mobile station based on the handshake frame, sending the measurement information frame to the indoor unit;

after receiving the configuration message frame sent by the indoor unit, sending the configuration message frame to the mobile station;

after receiving a configuration response message frame returned by the mobile station based on the configuration message frame, sending the configuration response message frame to the indoor unit;

and transmitting the received data frame transmitted by the indoor unit to the mobile station.

The mobile station may be configured to:

measuring channels between the candidate outdoor units and the mobile stations based on the handshake frames to obtain corresponding measurement information;

assembling the measurement information into a measurement information frame and sending the measurement information frame to a candidate outdoor unit;

after receiving the configuration message frame sent by the target outdoor unit, returning a corresponding configuration response message frame to the target outdoor unit;

receiving a data frame transmitted by a target outdoor unit.

Specifically, the signal processing flow of the signal processing system can be described as follows:

(1) the indoor unit selects N outdoor units from the plurality of outdoor units to form a group of transmission branches;

(2) the indoor unit organizes a handshake frame and sends the handshake frame to the selected outdoor unit in the form of a baseband signal;

(3) the outdoor unit modulates the handshake frame into a short-wave radio frequency signal, locks a local clock to the synchronous timing of the SDH optical ring network by utilizing the timing function provided by the SDH optical ring network, and simultaneously sends the short-wave radio frequency signal through a short-wave antenna;

(4) the mobile station measures the channel information, time delay information and other measurement information of a channel between the outdoor unit and the mobile station through the received handshake frame, assembles the measurement information frame and sends the measurement information frame to the outdoor unit;

(5) the outdoor unit removes short wave frequency from the received measurement information frame, converts the measurement information frame into a baseband signal and sends the baseband signal to the indoor unit;

(6) the indoor unit carries out signal demodulation and decoding processing on the received baseband signal to determine a diversity transmission branch;

(7) the indoor unit indicates the transmitted time delay information to the outdoor unit corresponding to each diversity transmission branch according to the measurement information, so that the arrival time difference of the subsequent signals transmitted by each transmission branch at the mobile station side is minimum;

(8) the indoor unit transmits the baseband signal of the configuration message to each diversity-transmitting outdoor unit, each outdoor unit modulates the baseband signal to a short-wave radio frequency signal, and transmits the configuration message frame to the mobile station in a delayed manner according to corresponding time delay information; and receiving a configuration response message frame from the mobile station;

(9) the outdoor unit removes the short wave frequency from the radio frequency signal corresponding to the configuration response message frame to recover the baseband signal, and sends the baseband signal to the indoor unit for signal demodulation and decoding processing;

(10) after confirming that the configuration response message frame is received, the indoor unit sends baseband signals of data frames to the outdoor units corresponding to the diversity sending branches, each outdoor unit modulates the baseband signals to short-wave frequency band radio frequency signals, diversity sending is carried out on the signals to the mobile station, and multi-branch signals are received jointly on the side of the mobile station.

As an example, the embodiments of the present invention may be applied to the following scenarios, but it should be understood that the embodiments of the present invention are not limited thereto:

assuming that the indoor unit is located in beijing, and the transmission points are located in beijing, nigh, zhangjiang, west ampere and yinchuan respectively, and the mobile station is located in a certain sea area of the pacific, it can be seen that the distances from each transmission point to the mobile station are greatly different, the embodiment of the invention selects an appropriate diversity transmission branch, and adjusts the time advance of the selected diversity transmission branch, so that the signals of each branch can synchronously reach the mobile station.

In connection with the embodiment of fig. 1, the following more specific description of the embodiments of the present invention is provided:

referring to fig. 2, a flowchart illustrating steps of an embodiment of a signal processing method according to the present invention is shown, and the embodiment of the present invention is described from an access point side, and specifically may include the following steps:

step 201, obtaining measurement information corresponding to each transmission branch in a plurality of transmission branches deployed in a wide area;

it should be noted that the transmission branch herein may include the outdoor unit and the short wave antenna in the embodiment of fig. 1.

The transmission branch is deployed in a wide area and can be deployed in China or even all over the world. In practice, the distance between the transmitting branches may preferably be not less than 100 km.

In a preferred embodiment of the present invention, step 201 may include the following sub-steps:

a substep S11 of selecting a candidate transmission branch from the plurality of transmission branches;

in an embodiment of the present invention, the access point may select a candidate transmission branch from the transmission branches of the wide-area deployment, wherein the number of the selected candidate transmission branches is within the second interval.

The second interval may include a lower limit and an upper limit, and the upper limit of the second interval may be the upper limit of the number of transmission branches that can be supported by the access point, for example, when the upper limit of the second interval is 4, it indicates that the access point can only support a maximum of 4 transmission branches simultaneously. The lower limit of the second interval may be the minimum number of transmission branches required by the access point, for example, when the lower limit of the second interval is 1, it indicates that the access point needs 1 transmission branch at minimum.

It should be noted that the selection policy of the access point for the candidate transmission branches may be random selection or selection according to the proximity of the geographic locations, which is not limited in this embodiment of the present invention.

A substep S12 of transmitting handshake frames to the mobile station at the same frequency using the candidate transmission branches, respectively;

for convenience of the following description, it is assumed that the number of candidate transmission branches is N, and as a preferred example, N may be 4.

To facilitate management of the selected candidate transmission branches, after the N candidate transmission branches are selected, the N candidate transmission branches may be grouped into one group and each group may be sequentially named, for example, a group composed of the N candidate transmission branches selected for the first time is named group 1, a group composed of the N candidate transmission branches selected for the second time is named group 2, …, a group composed of the N candidate transmission branches selected for the k time is named group k, and so on.

On a time axis, the indoor unit continuously assembles handshake frames according to the structure of the handshake frames, converts the handshake frames into baseband signals and sends the baseband signals to each candidate sending branch, and after each candidate sending branch receives the baseband signals indicating the handshake frames, the baseband signals are modulated into short-wave radio frequency signals, and the handshake frames are sent to the mobile station in the form of short-wave radio frequency signals, wherein the signal frequency of the handshake frames sent by each candidate sending branch is the same, so that compared with a single-path sending branch, no extra frequency is occupied.

As a preferred example of the embodiment of the present invention, each handshake frame may include at least a first handshake pilot and an access slot.

Further, to ensure the integrity of the first handshake pilot when detected, as an example, as shown in table 1, each handshake frame may include 2 first handshake pilots with a length of L1 and 3 access slots with a duration of Tw, where Tw is L1 × Ts, and Ts represents a transmission duration of one modulation symbol, and for example, Ts may be 0.4 ms.

First handshake pilot

First handshake pilot

Access time slot 1

Access slot 2

Access slot 3

TABLE 1

In an embodiment of the present invention, the first handshake pilot may be used to identify a corresponding transmission branch. The first handshake pilot of each candidate transmission branch may include a pseudo random sequence with equal length, wherein the pseudo random sequence is formed by cyclic shifting the same basic sequence and has a characteristic of strong autocorrelation.

In a specific implementation, each pseudo-random sequence may include L1 modulation symbols, with a corresponding duration Tw.

As an example, the base sequence may include a sequence having a good autocorrelation, such as an m-sequence or a Zadoff-Chu sequence (referred to as a Z-C sequence), where elements of the m-sequence are real numbers and elements of the Z-C sequence are complex numbers.

In one implementation, assuming that the base sequence is denoted as M [ n ], M [ n ] may include the following 6 sequences:

first, based on a basic sequence M [ n ] of 127 with a length L1 of M-sequence, n takes the value 1 … 127, and the specific values are as follows:

{-1,-1,-1,-1,-1,-1,-1,1,1,1,-1,-1,-1,1,-1,-1,1,1,1,-1,1,-1,1,1,-1,1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,1,1,1,1,-1,1,-1,-1,1,-1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,1,-1,1,-1,-1,1,1,-1,-1,1,1,1,1,1,-1,-1,1,-1,-1,1,-1,1,-1,-1,-1,1,-1,1,1,1,-1,-1,1,1,-1,1,1,1,-1,1,1,1,1,1,1,-1,1,1,-1,1,1,-1,-1,1,-1,1,1,-1,-1,-1,-1,1,-1,-1,-1,1,1,1,1}；

secondly, based on the basic sequence M [ n ] of 255 with the length L1 of the M-sequence, n takes the value 1 … 255, and the specific values are as follows:

{-1,-1,-1,-1,-1,-1,-1,-1,1,1,-1,1,1,1,1,-1,1,-1,1,1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,1,-1,-1,-1,1,1,1,1,1,-1,-1,1,1,1,-1,1,-1,1,-1,-1,1,1,-1,-1,1,1,-1,1,-1,-1,-1,-1,-1,-1,1,-1,-1,-1,-1,1,1,-1,-1,1,-1,-1,-1,1,-1,-1,-1,1,1,-1,1,-1,1,-1,1,1,-1,1,-1,1,1,1,-1,1,1,-1,1,-1,-1,1,-1,1,1,1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,-1,1,1,1,-1,-1,1,-1,-1,1,1,1,1,-1,1,1,1,-1,1,-1,-1,-1,1,-1,1,-1,-1,-1,-1,1,-1,-1,1,-1,-1,-1,-1,-1,1,1,1,1,-1,-1,1,-1,1,1,-1,-1,1,-1,1,-1,-1,1,-1,-1,1,-1,1,-1,1,1,1,1,1,-1,1,1,-1,-1,-1,1,-1,-1,1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,1,1,1,-1,-1,-1,1,-1,1,1,-1,1,1,1,-1,-1,-1,1,1,1,-1,1,1,1,1,1,1,1,-1,1,-1,-1,1,1,1,-1,-1,-1,-1,1,-1,1,1,1,1}；

thirdly, based on the base sequence M [ n ] of 511 that the length L1 of the M-sequence is, n takes the value 1 … 511, and the specific values are as follows:

{-1,-1,-1,-1,-1,-1,-1,-1,-1,1,1,-1,1,-1,1,1,-1,-1,1,1,1,-1,1,-1,-1,1,1,-1,-1,1,-1,-1,-1,1,1,1,1,1,1,-1,-1,1,1,-1,-1,1,1,-1,1,-1,-1,-1,1,-1,1,1,-1,1,-1,1,1,1,-1,-1,-1,-1,1,1,1,-1,-1,1,-1,1,-1,1,-1,1,1,-1,1,-1,-1,1,-1,1,1,1,-1,-1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,1,-1,-1,-1,-1,-1,1,1,1,-1,1,1,1,-1,1,-1,-1,-1,1,1,1,-1,1,-1,1,1,-1,1,1,-1,-1,1,-1,-1,1,1,-1,-1,-1,-1,1,1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,1,-1,-1,1,1,1,1,1,-1,1,1,1,1,-1,1,-1,-1,1,-1,-1,1,-1,1,1,-1,-1,1,-1,1,1,-1,1,1,1,-1,-1,1,1,-1,1,1,-1,1,-1,1,-1,1,1,1,1,1,1,-1,1,1,-1,1,1,-1,1,1,1,1,-1,-1,-1,1,-1,1,1,1,1,1,-1,-1,-1,-1,1,-1,1,1,1,-1,1,1,1,1,1,1,1,1,-1,1,-1,-1,-1,-1,1,-1,1,-1,1,1,-1,-1,-1,1,-1,1,-1,1,-1,-1,1,1,-1,1,1,1,1,1,-1,1,-1,1,-1,1,-1,1,-1,-1,-1,1,1,-1,-1,-1,1,-1,-1,-1,-1,1,1,-1,1,1,1,-1,1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,1,-1,-1,-1,1,-1,-1,-1,1,1,-1,1,-1,-1,1,1,1,-1,-1,1,1,1,1,-1,1,-1,1,1,1,1,-1,1,1,-1,-1,1,1,-1,-1,-1,1,1,-1,1,1,-1,-1,-1,-1,1,-1,-1,1,-1,1,-1,-1,1,-1,1,-1,1,1,1,-1,1,-1,1,-1,-1,-1,-1,1,1,1,1,-1,-1,1,-1,1,1,1,1,-1,-1,1,1,1,-1,-1,-1,1,-1,-1,1,-1,-1,-1,1,-1,1,-1,-1,-1,1,-1,-1,1,1,-1,1,-1,1,-1,-1,1,-1,-1,-1,-1,-1,-1,1,1,1,1,1,-1,-1,1,-1,-1,1,-1,-1,1,1,1,-1,1,1,-1,-1,-1,1,1,1,1,-1,1,1,1,-1,-1,-1,1,1,-1,-1,1,1,1,1,1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,-1,-1,1,-1,1,1,-1,-1,-1,-1,-1,-1,1,-1,1,-1,-1,1,1,1,1}；

fourthly, based on a basic sequence M [ n ] with the length of 127 of the Zadoff-Chu sequence, n takes the value of 1 … 127, and the specific value is shown in the following formula:

fifthly, based on a basic sequence M [ n ] with the length of 251 of the Zadoff-Chu sequence, n takes a value of 1 … 251, and the specific value is shown in the following formula:

sixthly, based on a basic sequence M [ n ] with the length of 509 of the Zadoff-Chu sequence, n takes a value of 1 … 509, and the specific value is shown in the following formula:

in the embodiment of the present invention, in order to ensure that the receiving station can identify the corresponding candidate transmission branch from the first handshake pilot, the embodiment of the present invention uses a cyclic shift method to form a pseudo-random sequence that is actually used for each candidate transmission branch, starting from the basic sequence.

Specifically, the first handshake pilot of each candidate transmission branch may be formed by cyclically shifting the base sequence of the m-sequence or Zadoff-Chu sequence by MV symbols at equal intervals, for example, when there are 4 candidate transmission branches, the number of cyclic right shifts of candidate transmission branch 1 with respect to the base sequence is 0, the number of cyclic right shifts of candidate transmission branch 2 with respect to the base sequence is MV, the number of cyclic right shifts of candidate transmission branch 3 with respect to the base sequence is 2MV, and the number of cyclic right shifts of candidate transmission branch 4 with respect to the base sequence is 3 MV.

The following takes the candidate transmission branch as 4 branches as an example, and exemplifies the procedure of the cyclic shift:

assuming that MV is 30 for 127-length sequences, MV is 60 for 255-or 251-length sequences, and MV is 120 for 511-or 509-length sequences, the handshake pilots of 4 branches formed by the cyclic shift method are:

candidate transmission branch 1: m1[1.. L1] ═ M [1.. L1 ];

candidate transmission branch 2: m2[1.. MV ] ═ M [ (L1-MV + 1.. L1]

M2[(MV+1)..L1]＝M[1..(L1-MV)]；

Candidate transmission branch 3: m3[1..2 × MV ] ═ M [ (L1-2 × MV + 1.. L1]

M3[(2*MV+1)..L1]＝M[1..(L1-2*MV)]；

Candidate transmission branch 4: m4[1..3 × MV ] ═ M [ (L1-3 × MV + 1.. L1]

M4[(3*MV+1)..L1]＝M[1..(L1-3*MV)]。

The embodiment of the invention adopts a plurality of transmitting antennas distributed in a wide area to simultaneously transmit diversity signals irrelevant to spatial fading to the terminal, and because the transmitting points have large difference in geographic position, the independence of channels from the transmitting points to the mobile station is good, and the probability of deep fading when a plurality of transmitting branches occur is small, thereby effectively improving the communication performance of a short wave system.

And a substep S13, receiving a measurement information frame returned by the mobile station based on the handshake frame, and respectively obtaining the measurement information corresponding to the candidate transmission branches based on the measurement information frame.

In a specific implementation, 1 transmitting antenna and 1 receiving antenna may form 1 channel, and if there are 4 candidate transmitting branches, there may be 4 transmitting antennas and 1 receiving antenna, that is, there are 4 channels.

The measurement information is obtained after the mobile station measures the channel between the corresponding candidate transmission branch and the mobile station based on each handshake frame.

Specifically, for a mobile station, after receiving a signal over the air interface, a first handshake pilot may be first detected from the received signal.

In one embodiment, the mobile station may detect the first handshake pilot from the received signal as follows:

taking a signal with a first preset threshold duration from the received signal, and sliding by taking the first preset threshold as a step length; and when the signals obtained after sliding comprise non-handshake pilot signals, continuing sliding by taking a first preset threshold as a step length until the signals obtained after sliding only comprise signals of the first handshake pilot, and determining that the first handshake pilot is detected.

In a specific implementation, the first preset threshold duration may be a duration of 1 first handshake pilot, for example, if the duration of 1 first handshake pilot is Tw, the mobile station may arbitrarily fetch Tw-duration data from the received signal Sig and slide with Tw as a step size, and this operation of the mobile station is referred to as windowing.

Specifically, since the spatial distance between the access point and the mobile station is variable (because the location of the mobile station is variable) and the radio propagation takes time, the mobile station does not know when the access point sends a handshake frame, and only continuously receives signals from the air interface and then continuously detects the handshake frame from the received signals.

In this embodiment of the present invention, after receiving a radio frequency signal Sig from an air interface, a mobile station may arbitrarily fetch Tw-duration data from the radio frequency signal for detection, however, since a handshake frame sent by an access point includes 3 access slots (taking the handshake frame structure of table 1 as an example), when the Tw-duration data fetched by the mobile station includes or partially includes a non-handshake pilot signal (for example, the non-handshake pilot signal may include data of the access slot and/or noise floor, etc.), the fetched data may affect the effect of subsequent measurement, and therefore, when the fetched Tw-duration data includes or partially includes the non-handshake pilot signal, the data may be slid by taking Tw as a step length to continue to fetch data for detection until the fetched Tw-duration data does not include data of the access slot, and includes only one complete first handshake pilot.

For example, as shown in the window-taking process diagram of fig. 3, since the handshake frame includes 2 first handshake pilots with length L1, according to fig. 3, a complete handshake pilot can be detected by performing a sliding window for at most 5 times (the handshake pilot in fig. 3 is the first handshake pilot).

In implementation, when a window is taken in a received radio frequency signal according to a duration Tw, a time corresponding to a lower edge of a time number in the window may be recorded as Tbase (in us). As shown in fig. 3, Tbase is marked on the left side of each window as the time corresponding to the lower edge of the time number in the window.

After detecting the first handshake pilot, the mobile station may measure channels between the corresponding candidate transmit branches and the mobile station based on the first handshake pilot to obtain corresponding measurement information, and then assemble the measurement information corresponding to each candidate transmit branch into a measurement information frame.

As an example, the measurement information frame may include the second handshake pilot as well as the measurement information. The second handshake pilot frequency is a pseudo-random sequence; the measurement information may include at least, but is not limited to: channel information for each candidate transmit branch. The channel information may include, but is not limited to: frequency offset value FreqOffset, amplitude peak-to-average ratio of correlation peak PtoA, etc.

The frequency offset value is a doppler shift due to a channel change during signal propagation (when a mobile station moves in a certain direction at a constant speed, a phase and a frequency change due to a propagation path difference is referred to as a doppler shift), and a small frequency offset value means a long correlation time.

The amplitude peak-to-average ratio of the correlation peak is a measure of the signal propagation capability of the channel, and a large amplitude peak-to-average ratio means that the channel attenuation is reduced.

In the embodiment of the present invention, the transmission time point of the measurement information frame may be located after 2 first handshake pilots of the handshake frame transmitted by the candidate transmission branch, and placed in the access slot. In one embodiment, referring to the measurement information frame diagram of fig. 4, the information data (i.e. the measurement information) may be modulated by BPSK (Binary Phase Shift Keying), and to reduce the transmission amount, the measurement information may be encoded as follows: and 39bits in total, and adopts cyclic error correction coding of the length 63 and the effective data 39 bits.

Wherein, the effectiveness of the candidate transmitting branch comprises 4bits, each bit represents 1 transmitting antenna; '0' means invalid, '1' means valid;

the number of the candidate transmission branch that arrives latest (i.e. the branch corresponding to MaxST) includes 2bits, '00' indicating the branch corresponding to the M1 pilot, '01' indicating the branch corresponding to the M2 pilot, '10' indicating the branch corresponding to the M3 pilot, and '11' indicating the branch corresponding to the M4 pilot;

the TimeDelay comprises 21bits, each transmission branch occupies 7bits, and the maximum time can be adjusted by 25.4ms by taking Ts/2 as a time unit;

FreqOffset comprises 8bits, wherein each transmission branch occupies 2bits, '00' indicates that the frequency offset is within 1Hz, '01' indicates that the frequency offset is above 1Hz but within 2Hz, '10' indicates that the frequency offset is above 2Hz but within 4Hz, '11' indicates that the frequency offset is above 4 Hz;

PtoA comprises 4bits, with 1bit per transmit branch, a '0' value indicating a value greater than the threshold Thres2 but less than Thres 1; '1' indicates that the value exceeds the threshold Thres 1.

In a specific implementation, after the mobile station detects the first handshake pilot, the mobile station may perform a correlation operation with a signal received over the air interface by using a pseudo-random sequence (M1, M2, M3, M4) corresponding to the first handshake pilot, to obtain channel information of a channel between the corresponding candidate transmission branch and the mobile station.

In a preferred embodiment of the present invention, the step of measuring, by the mobile station, the channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot, and obtaining the measurement information of the channel may include the following sub-steps:

a) converting the pseudo-random sequence of the first handshake pilot into a frequency domain sequence;

in a specific implementation, for the ith candidate transmission branch, obtaining a pseudorandom sequence corresponding to a first handshake pilot of the candidate transmission branch, assuming that the sequence is M1, performing root raised cosine processing on M1 to form a time domain baseband sequence TB with a length of (L1 × C), wherein when the root raised cosine processing is performed, the roll-off coefficient α may preferably be 0.2, the oversampling multiple C may be 2 times or more, and the duration Tc of each sampling point is Ts/C; the TB is then transformed into the frequency domain using fast fourier transform, resulting in a frequency domain sequence FB.

b) Acquiring a radio frequency signal from an air interface, converting the radio frequency signal into a baseband signal according to a specified frequency offset value, and converting the baseband signal into a frequency domain signal;

in a specific implementation, the radio frequency signal acquired from the air interface can be marked as Sig, a specified frequency offset value is adopted for Sig to remove a modulation carrier, and filtering is carried out to obtain a baseband signal TSig, wherein the sampling point number of TSig is L1 × C; transforming TSig into frequency domain by fast Fourier to form FSig; the following methods can be used:

TSig(ii)＝I(ii)-jQ(ii)；

and I (ii) ═ cos (2 pi (fc + Δ f) × (ii-1) × Ts/C) × Sig (ii);

Q(ii)＝sin(2π(fc+Δf)*(ii-1)*Ts/C)*Sig(ii)；

wherein ii represents a sample point subscript, which may take the value of 1.. L1 × C; sig (ii) represents the value of the air interface signal at sample point ii; fc represents an air interface frequency or an intermediate frequency; delta f represents a designated frequency offset value, the designated frequency offset value can be selected from a preset frequency offset value range, the frequency offset value range can be-10 Hz to +10Hz according to the characteristics of a short-wave channel, the granularity is 0.25Hz, and the embodiment of the invention assumes that the fixed frequency offset of the equipment at the transmitting end and the receiving end is obtained by calibration in advance and is not considered any more.

In practice, the number of samples of TSig can be determined as follows: for example, the air interface samples according to 20kHz, and for an m-sequence of 127 length, when each symbol duration Ts of the m-sequence is 0.4ms (i.e., 2500Hz), there are 127 × 20K/2500-1016 air interface signals of the m-sequence of 127 length, i.e., i takes 1.. 1016.

c) Calculating a channel estimation vector based on the frequency domain signal and the frequency domain sequence;

specifically, after obtaining the frequency domain signal and the frequency domain sequence, the frequency domain signal and the frequency domain sequence may be subjected to a correlation operation to obtain a channel estimation vector corresponding to the channel.

In a specific implementation, the correlation operation between the frequency domain signal and the frequency domain sequence can be expressed in the frequency domain as a complex conjugate product, as shown in the following formula:

FCorrelation＝FSig*conj(FB)，

where, conj represents the conjugation.

After obtaining the frequency domain result fcation vector, the fcation vector can be further transformed to the time domain by inverse fourier transform to obtain the channel estimation tcation vector.

d) Traversing the frequency offset values in the frequency offset value range to obtain a plurality of channel estimation vectors;

in a specific implementation, in order to obtain the frequency offset estimation value, various Δ f may be continuously tried within the frequency offset range to obtain the corresponding TCorrelation vector.

e) Obtaining the average value of the amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and recording the average value as an amplitude average value; obtaining the maximum value of the amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and recording the maximum value as an amplitude peak value; calculating the ratio of the amplitude peak value to the amplitude mean value aiming at each channel estimation vector in the plurality of channel estimation vectors to obtain an amplitude peak-to-mean ratio;

in a specific implementation, each channel estimation vector may include a plurality of amplitude absolute values, a maximum amplitude absolute value of the plurality of amplitude absolute values may be used as an amplitude Peak of the channel estimation vector, and an average value of the plurality of amplitude absolute values may be calculated to obtain an amplitude average Avg.

After the amplitude Peak value Peak and the amplitude average value Avg of each channel estimation vector are obtained, the amplitude Peak-to-average ratio PtoA [ i ] of the channel estimation vector can be obtained by calculation according to a formula PtoA [ i ] ═ Peak/Avg; where i denotes the number of the candidate transmission branch, i.e., i ═ 1, denotes that the pseudorandom sequence M1 is being detected; i-2, indicating that the pseudorandom sequence M2 is being detected; i-3, indicating that the pseudorandom sequence M3 is being detected; i-4, indicating that the pseudorandom sequence M4 is being detected.

f) Selecting a channel estimation vector with the maximum amplitude peak-to-average ratio from the plurality of channel estimation vectors, recording the channel estimation vector as the maximum amplitude peak-to-average ratio, and recording a frequency offset value corresponding to the maximum amplitude peak-to-average ratio;

in the implementation, after trying to obtain a plurality of TCorrelation vectors by various Δ f and calculating the amplitude peak-to-average ratio of each TCorrelation vector, the maximum value among the amplitude peak-to-average ratios of the plurality of TCorrelation vectors can be found and recorded as the maximum amplitude peak-to-average ratio, and Δ f when the maximum amplitude peak-to-average ratio is obtained is recorded, and the frequency offset FreqOffset [ i ] corresponding to the maximum amplitude peak-to-average ratio is recorded as Δ f.

In practice, the subscript value of the TCorrelation vector corresponding to the maximum amplitude peak-to-average ratio can also be recorded as PeakIndex [ i ].

According to the above method, the mobile station may obtain the maximum amplitude peak-to-average ratio of each candidate transmission branch i (i.e. for the sequences M1, M2, M3, M4), and according to the subscript value PeakIndex [ i ] of the TCorrelation vector corresponding to the maximum amplitude peak-to-average ratio, the mobile station may calculate the absolute time FrameST [ i ] where the frame header of the handshake frame of the candidate transmission branch i is located by using the following formula: FrameST [ i ] ═ Tbase- (L1 × C-PeakIndex [ i ] +1) × Tc.

Assuming that the maximum amplitude peak of the window (total length is 127 symbol lengths) corresponding to Tbase is at 32 symbol positions, the starting time point of the first handshake pilot can be calculated to be at Tbase- (127-32+1) × Ts, the starting time point of the first handshake pilot is determined, and the mobile station can determine the ending time point of the first handshake pilot according to the calculation formula of FrameST [ i ].

g) If the maximum amplitude peak-to-average ratio is smaller than a second preset threshold value, judging that the candidate sending branch is invalid; and if the maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold value, judging that the candidate sending branch is effective.

As an example, the measurement information may also include the validity of each candidate transmission branch. In an implementation, the validity may be marked with a valid identification or an invalid identification.

Specifically, after the maximum amplitude peak-to-average ratio of the candidate transmission branch i is obtained, comparing the maximum amplitude peak-to-average ratio with a second preset threshold (which may be labeled as Thres2), and if the maximum amplitude peak-to-average ratio of the branch i is smaller than Thres2, considering that the candidate transmission branch is invalid, and adding an invalid identifier to the candidate transmission branch; otherwise, if the maximum amplitude peak-to-average ratio of the branch i is greater than or equal to Thres2, the candidate transmission branch is considered to be valid, and a valid identifier is added to the candidate transmission branch.

In a preferred embodiment of the present invention, the step of measuring, by the mobile station, the channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot, and obtaining the measurement information of the channel may further include the following sub-steps:

h) when the candidate sending branch is judged to be invalid, sliding by taking a third preset threshold as a step length, and continuously executing the steps b) -g);

in an implementation, the third preset threshold may be a value of the duration Lw (L1 × C sampling points).

In practical applications, if a candidate transmission branch does not transmit a signal to the mobile station, the mobile station obtains a detection result when detecting the transmission branch that is invalid, but the candidate transmission branch may subsequently transmit a signal to the mobile station.

i) When the candidate sending branch is judged to be effective, performing window taking at the position of the next first handshake pilot frequency of the candidate sending branch, and continuously executing the detection processes of b) -f) to obtain a new maximum amplitude peak-to-average ratio; recording a subscript value of a channel estimation vector corresponding to the new maximum amplitude peak-to-average ratio, and if the subscript value is smaller than a preset oversampling multiple and the new maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold, determining that the candidate transmission branch is valid; and if the subscript value is greater than or equal to a preset oversampling multiple and/or the new maximum amplitude peak-to-average ratio is less than a second preset threshold, determining that the candidate transmission branch is invalid.

The position of the next first handshake pilot of the candidate transmission branch may be (FrameST [ i ] + L1 × C × Tc).

In a specific implementation, in order to prevent the occurrence of the disguised amplitude peak and ensure the accuracy of the amplitude peak detection, if the maximum amplitude peak-to-average ratio of the branch i is greater than or equal to Thres2, the following confirmation procedure may be performed:

for candidate transmit branch i, the mobile station takes the position of (FrameST [ i ] + L1 × C × Tc) as Tbase of the taking window, and performs the processing of b) -f) on the time domain samples in the taking window to obtain a new maximum amplitude peak-to-average ratio and the corresponding peakendex [ i ].

If the new PeakIndex [ i ] < C and the maximum amplitude peak-to-average ratio exceeds the threshold Thres2, the candidate sending branch is considered to be valid; otherwise, if peakIndex [ i ] > -C and/or the maximum amplitude peak-to-average ratio is less than the threshold Thres2, the transmit branch is considered invalid and step h) is performed.

In a preferred embodiment of the present invention, the measurement information may further include delay information of each valid candidate transmission branch, a number of a candidate transmission branch that arrives latest, and the like, and the step of the mobile station measuring a channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot may further include the following sub-steps:

j) when a preset timer in a mobile station is overtime, determining effective candidate transmitting branches from the candidate transmitting branches; respectively acquiring the absolute time of the frame headers of the handshake frames of the effective candidate sending branches; selecting the candidate transmission branch with the maximum absolute time from the effective candidate transmission branches as the latest arrival transmission branch; and calculating the difference value between the absolute time of other candidate transmission branches and the absolute time of the latest arriving transmission branch as the time delay information of other transmission branches.

In a specific implementation, a detection timer is set in the mobile station, a corresponding time duration is set for each group of antennas, when the time duration reaches, the detection of the group of antennas is stopped, and the effective time delay information of the candidate transmission branch is determined according to the following method:

determining valid candidate transmission branches detected in the handshake pilots (M1, M2, M3, M4), then finding the element MaxST of the maximum value in the FrameST [ i ] array, corresponding to the transmission branch that arrives the latest (this branch is taken as a branch that does not need to be delayed), and forming corresponding time adjustment (delay information) for other candidate transmission branches in the same group: TimeDelay [ i ] ═ MaxST-FrameST [ i ].

For example, if the candidate transmission branch arriving at the latest is branch 2, and the absolute time corresponding to branch 2 is 13 minutes, 20 seconds, 50ms100us, the time delay information "TimeDelay" field means that the other candidate transmission branches are ahead of the time value of branch 2, for example, the absolute time of branch 1 is 13 minutes, 20 seconds, 35ms50us, and the TimeDelay corresponding to branch 1 is 15ms +50 us.

The measurement information of each candidate transmission branch can be obtained according to the processes a) to j), and of course, a person skilled in the art may also obtain the measurement information of each candidate transmission branch in other manners, which is not limited in the embodiment of the present invention.

After obtaining the measurement information of each candidate transmission branch, the mobile station constructs a measurement information frame based on each measurement information, and transmits the measurement information frame to the access point to report channel information and delay information to the access point.

It should be noted that, a measurement information frame sent by a mobile station to an access point may be sent to the access point through one channel, or may be sent to the access point in multiple channels in the form of multiple copies, which is not limited in this embodiment of the present invention.

And a substep S14, if there are unselected transmission branches in the transmission branches, continuing to execute the substeps S11-substep S13 until all the transmission branches are measured.

In a specific implementation, each group of transmission branches includes N candidate transmission branches, and the access point may interact with the mobile station multiple times to obtain measurement information of multiple groups of transmission branches. Specifically, if there are unmeasured transmission branches to be selected at the access point side, the antenna group number k is increased by 1, and the access point side sets up a new antenna group k including 4 antennas unmeasured by the mobile station at most; according to the substeps S11-S13, the access point transmits a handshake frame on the antenna group and receives a measurement information frame transmitted by the mobile station; if the access point has no unmeasured transmission branches to be selected, it is determined that the transmission branches are detected completely, and the process continues to step 202.

Step 202, selecting a target transmission branch from the plurality of transmission branches based on the measurement information;

the number of target transmission branches is within the first interval range, and it should be noted that the upper limit of the first interval range may be the upper limit of the number of transmission branches that can be supported by the access point, for example, when the upper limit of the first interval range is 4, it indicates that the access point can only support a maximum of 4 transmission branches simultaneously.

After the access point obtains the measurement information of the multiple transmission branches, it may determine the effective transmission branches, and select one or more transmission branches from the effective transmission branches as target transmission branches.

In a preferred embodiment of the present invention, step 202 may comprise the following sub-steps:

a substep S21 of selecting a valid transmission branch from the plurality of transmission branches based on the measurement information corresponding to each transmission branch, when the plurality of transmission branches have been measured;

after the access point has obtained the measurement information for the multiple transmit branches, it may select a valid transmit branch from the multiple transmit branches based on the validity indicated in the measurement information.

Substep S22, dividing the effective transmission branch into two first sets according to the comparison result of the amplitude peak-to-average ratio and a fourth preset threshold;

in practical applications, the fourth preset threshold may be labeled Thres1, where Thres1 is greater than Thres 2.

When the access point screens out effective transmission branches from a plurality of transmission branches, the value of the amplitude peak-to-average ratio PtoA of each effective transmission branch can be obtained. The access point may divide the active transmission branches into 2 first sets according to the value of the amplitude peak-to-average ratio PtoA of each active transmission branch.

In one embodiment, the access point may categorize transmission branches having a PtoA value exceeding a threshold Thres1 in a first set of branches 1, and transmission branches having a PtoA value exceeding a threshold Thres2 but less than Thres1 in a second first set of branches 2.

For example, the access point may record the active transmit branch for PtoA taking a '1' in branch 1 and the active transmit branch for PtoA taking a '0' in branch 2.

Substep S23, dividing the effective transmission branches into four second sets according to the frequency offset value;

in a specific implementation, after the access point screens out valid transmission branches from the plurality of transmission branches, a frequency offset value of each valid transmission branch may be obtained. According to the frequency offset value of each effective transmission branch, the access point may divide the effective transmission branches into 4 second sets, which are denoted as branch [ j ], and j takes a value of 1 … 4.

In one embodiment, the access point may group active transmit branches having a frequency offset of no more than 1Hz in a first second set of branch [1], active transmit branches having a frequency offset of no more than 2Hz in a second set of branch [2], active transmit branches having a frequency offset of no more than 4Hz in a third second set of branch [3], active transmit branches having a frequency offset of more than 4Hz in a fourth second set of branch [4 ].

A substep S24, performing intersection operation on the first set and the second set respectively to form a plurality of intersection sets;

in one embodiment, the intersection set of the two first sets and the four second sets may include:

InterSet_11＝BranchThres1∩BranchSet[1]；

InterSet_12＝BranchThres1∩BranchSet[2]

InterSet_13＝BranchThres1∩BranchSet[3]；

InterSet_14＝BranchThres1∩BranchSet[4]

InterSet_21＝BranchThres2∩BranchSet[1]；

InterSet_22＝BranchThres2∩BranchSet[2]。

wherein, InterSet _11 is a set of transmission branches with amplitude peak-to-average ratio better than Thres1 and frequency offset value not more than 1 Hz;

InterSet _12 refers to the set of transmit branches with amplitude peaks better than Thres1 and frequency offset values exceeding 1Hz but not exceeding 2 Hz;

InterSet _13 refers to the set of transmit branches with amplitude peaks better than Thres1 and frequency offset values exceeding 2Hz but not exceeding 4 Hz;

interset _14 refers to the set of transmit branches with amplitude peaks better than Thres1 and frequency offset exceeding 4 Hz;

interset _21 refers to a set of transmission branches with amplitude peak-to-average ratio better than Thres2 but less than Thres1 and frequency offset value not exceeding 1 Hz;

interset _22 refers to the set of transmit branches with amplitude peak-to-average ratio better than Thres2 but less than Thres1, and frequency offset value over 1Hz but not over 2 Hz.

In implementation, since a small amplitude peak-to-average ratio means that channel attenuation is large, and a large frequency offset value means that correlation time is short, in order to improve the effect of correlation operation, the embodiment of the present invention may filter out a set with large channel attenuation and short correlation time. For example, the set of transmission branches with amplitude peak-to-average ratio better than Thres2 but less than Thres1 and frequency offset value exceeding 2Hz (i.e., InterSet _23 ═ branched sequences 2 ═ branched sequences [3 ]; InterSet _24 ═ branched sequences 2 ∞ branched sequences [4]) is filtered out.

A substep S25, performing union operation on the plurality of intersection sets respectively to form a union set;

after the multiple intersection sets are combined, the embodiment of the present invention may further perform union operation on the multiple intersection sets to obtain a union set.

In an embodiment, a partial intersection set may be selected from the 6 intersection sets to perform union operation, so as to obtain a union set, where the specific process is as follows:

UnionSet_11_12＝(InterSet_11∪InterSet_12)；

UnionSet_11_21＝(InterSet_11∪InterSet_21)；

UnionSet_12_22＝(InterSet_12∪InterSet_22)；

UnionSet_13_14＝(InterSet_13∪InterSet_14)。

wherein, UnionSet _11_12 refers to a set of transmission branches with amplitude peak-to-average ratio better than Thres1 and frequency offset value not exceeding 2 Hz;

UnionSet _11_21 refers to a set of transmission branches with amplitude peak-to-average ratio better than Thres2 and frequency offset value not exceeding 1 Hz;

UnionSet _12_22 refers to a set of transmit branches with amplitude peak-to-average ratio better than Thres2 and frequency offset value exceeding 1Hz but not exceeding 2 Hz;

UnionSet _13_14 refers to the set of transmit branches with amplitude peaks better than Thres1 and frequency offsets in excess of 2 Hz.

In a specific implementation, the embodiment of the present invention may filter out a union set with large channel attenuation and short correlation time, for example, filtering out UnionSet _11_13 (InterSet _11 ═ InterSet _ 13); UnionSet _11_14 ═ (InterSet _11 ═ InterSet _ 14); UnionSet _11_22 ═ (InterSet _11 ═ InterSet _22), and the like.

In order to make those skilled in the art better understand the formation process of the intersection set and the union set, the following describes the process as an example, but it should be noted that the embodiments of the present invention are not limited thereto:

a) assuming that there are ten transmission branches, each having a branch number of 0 … 10, and the branch numbers of the transmission branches are {0, 1, 3, 5} in the branch 1 set, and {1, 2, 3} in branch [1], according to the feedback situation of the mobile station, the InterSet _11 is {1, 3 }.

b) Assuming that {0, 4} is included in branch [2], set _12 is {0 };

c) for UnionSet _11_12, which refers to a set of transmit branches with better peak-to-average amplitude ratio than Thres1 and no frequency offset exceeding 2Hz, UnionSet _11_12 ═ 0, 1, 3.

Substep S26, determining a selection order of the intersection set and/or the union set according to the amplitude peak-to-average ratio and the frequency offset value, and sorting sets with larger amplitude peak-to-average ratio and/or smaller frequency offset value in the selection order;

for example, in the above intersection combination and/or union combination, the determined selection order may be, according to the principle that the sets with larger amplitude peak-to-average ratio and/or smaller frequency offset value are sorted in the first order: InterSet _11, unitset _11_12, InterSet _12, unitset _11_21, InterSet _13, unitset _12_22, InterSet _22, unitset _13_14, and InterSet _ 14.

Substep S27, selecting the upper limit sending branches of the first interval from the corresponding intersection combination and/or union set as target sending branches according to the selection order, wherein for each intersection combination, the sending branches are randomly selected;

in a specific implementation, after the selection order is obtained, the upper-limit branch-expected sending branches of the first interval may be selected from the intersection set according to the selection order as the target sending branches.

For each union combination, the target transmission branches may be selected in the order of InterSet _11, InterSet _12, InterSet _13, InterSet _14, InterSet _21, and InterSet _ 22. For each set of intersections, a send branch may be randomly selected.

In the embodiment of the invention, when the target transmission branch is selected, the data frame format of the target transmission branch can be determined.

As an example, the data frame format includes at least: the total time length of the data frame, the time length of the pilot symbols and the number of the pilot symbols of the data frame, the time length of the data symbols and the number of the data symbols, the modulation mode and the air interface rate.

In one embodiment, the data frame format may include, but is not limited to, the following, as shown in table 2:

TABLE 2

Based on the above table 2, according to the principle of selecting a target transmission branch from the sets with large amplitude peak-to-average ratio and small frequency offset as much as possible, the configuration policy of the data frame format of the target transmission branch selected in each intersection set or union set is as follows:

for example, if the number of transmission branches in the set InterSet _11 is greater than or equal to branched, the data frame format may adopt the format number 1 of table 2;

if the number of sending branches in the set UnionSet _11_12 is greater than or equal to BranchExpected, the data frame format may adopt the format number 2 of Table 2;

if the number of transmission branches in the set InterSet _12 is greater than or equal to branched, the data frame format may adopt the format number 2 of table 2;

if the number of transmission branches in the set UnionSet _11_21 is greater than or equal to BranchExpected, the data frame format may adopt the format number 3 of Table 2;

if the number of transmission branches in the set InterSet _21 is greater than or equal to branched, the data frame format may adopt the format number 3 of table 2;

if the number of transmission branches in the set InterSet _13 is greater than or equal to branched, the data frame format may adopt the format number 4 of table 2;

if the number of sending branches in the set UnionSet _12_22 is greater than or equal to BranchExpected, the data frame format may adopt the format number 5 of Table 2;

if the number of transmission branches in the set InterSet _22 is greater than or equal to branched, the data frame format may adopt the format number 5 of table 2;

if the number of transmission branches in the set UnionSet _13_14 is greater than or equal to BranchExpected, the data frame format may adopt the format number 6 of Table 2;

if the number of transmit branches in the set InterSet _14 is greater than or equal to branched, the data frame format may employ format number 6 of table 2.

And a substep S28 of subtracting 1 from the upper limit of the first interval and continuing to execute the substep S27 if the number of the target transmission branches is less than the upper limit of the first interval.

In a specific sight, if the number of the target sending branches selected from the intersection set cannot reach the number of branch sending branches, the branch sending branches are reduced by 1, and at this time, if the branch sending branches are not 0, the substep S27 is continuously executed to select the target sending branches; if branch expected is 0, return to sub-step S12 to continue sending handshake frames.

As an example, the default is taken branch x desired to be 4.

In one embodiment, the branch target transmit branches may constitute antenna group Y.

In a preferred embodiment of the present invention, after determining the antenna group Y, the following steps may be further included: respectively adopting the target transmission branches to transmit handshake frames to the mobile station at the same frequency; and receiving a measurement information frame corresponding to the handshake frame returned by the mobile station.

After the antenna group Y is obtained, because the target transmission branches in the antenna group Y are not handshake and measured together, and the importance of the wide area diversity transmission alignment time is considered, the embodiment of the present invention can perform one-time handshake and measurement on the branched target transmission branches in the antenna group Y collectively.

The handshaking and measuring manners may be performed according to the sub-steps S12 and S13, and the embodiments of the present invention are not described herein again.

The embodiment of the invention selects the target sending branch by setting the principle of meeting the set number of branches, the maximized signal strength and the minimized frequency deviation, the system reliability can be effectively improved by the emission of a plurality of target sending branches, and meanwhile, the signal strength is maximized and the frequency deviation is small, which is beneficial to improving the transmission rate.

Step 203, respectively adopting the target transmission branches to transmit configuration message frames to the mobile station;

after receiving the measurement information corresponding to each first pilot frequency, the access point may transmit a configuration message frame by using the target transmission branch according to the measurement information, and the target transmission branch modulates the configuration message frame into a short-wave-band radio-frequency signal and transmits the short-wave-band radio-frequency signal to the mobile station.

As an example, the configuration message frame may include at least the following information: the device comprises a first handshake pilot, a first protection interval and configuration signaling data, wherein the configuration signaling data comprises a fixed symbol number, a fixed modulation symbol duration and a fixed modulation coding level. For example, as shown in the schematic diagram of the configuration message frame in fig. 5, the configuration message frame may include configuration signaling data of two first handshake pilots, one first guard interval (GAP), one fixed symbol number, a fixed modulation symbol duration, and a fixed modulation coding level.

As an example, the GAP length may be 10 Ts; the number of fixed symbols may be 31; the modulation symbol duration may be 4 Ts; the fixed modulation coding level may be BPSK, using cyclic error correction coding of length 31 and 11bits of payload data.

In practice, the configuration signaling data may be sent by space-time coding.

It should be noted that, the format of the first handshake pilot of each target transmission branch may refer to the format of the first handshake pilot in the handshake frame, and is not described herein again.

In practice, the content carried by the configuration signaling data in the configuration message frame is the configuration for the data frame, and then the configuration message frame may further include the following information: data frame format number: 3 bits; the interweaving depth is as follows: 2bits, '00' indicates 4 data frame lengths, '01' indicates 8 data frame lengths, '10' indicates 12 data frame lengths, '11' indicates 16 data frame lengths; coding rate: 3bits including 1/8, 1/4, 1/3, 1/2, 2/3, 3/4, 8/9, 9/16; fill symbol PAD: 3 bits.

After receiving the measurement information of each first handshake pilot, the access point may delay to transmit a corresponding configuration message frame at each target transmission branch of the antenna group Y according to the delay information TimeDelay [ i ] indicated in the measurement information, so that each target transmission branch may be aligned to a transmission branch corresponding to MaxST when the mobile station receives the configuration message frame.

In a preferred embodiment of the present invention, the method may further include the following steps:

starting a timer after the configuration message frame is sent; if the timer is overtime and the configuration response message frame is not received, the target transmission branch is adopted again to transmit the configuration message frame to the mobile station; and when the number of times of sending the configuration message frame is greater than a preset number threshold, if the configuration response message frame is not received, re-executing the step of selecting the candidate sending branch from the plurality of sending branches to re-determine the target sending branch.

Specifically, after each target transmission branch transmits a configuration message frame to the mobile station, the mobile station waits for a configuration response message frame corresponding to the configuration message frame to be returned.

In a specific implementation, the access point starts a timer TimerConfig on the access point side after sending the configuration message frame, and sends the configuration message frame to the mobile station again if the TimerConfig still does not receive the configuration response message frame returned by the mobile station after the TimerConfig times out, and if the configuration response message frame returned by the mobile station is still not received when the number of times of sending the configuration message frame for group Y is greater than a preset number threshold Nc, re-executes substep S11, selects another group of candidate sending branches and executes substeps 12-substep S27, and the access point again performs the process of sending the handshake frame and re-selecting the target sending branch.

It should be noted that the preset number threshold Nc may be set according to actual needs, for example, Nc may be set to be 4, which is not limited in this embodiment of the present invention.

Step 204, receiving a configuration response message frame corresponding to the configuration message frame returned by the mobile station;

for the mobile station, after detecting the first handshake pilot in the configuration message frame, it always tries to detect the configuration signaling data backwards according to the configuration message frame format of fig. 4.

If the error correction code of the configuration signaling data obtained by the mobile station is checked correctly, the mobile station considers that the configuration message frame is received, and at this time, the mobile station can send a configuration response message frame to the access point.

As an example, the configuration response message frame may include at least the following information: a third handshake pilot frequency and configuration response information, wherein the third handshake pilot frequency is a pseudo-random sequence; the configuration response information is used to indicate that the mobile station successfully received the configuration message frame. For example, as shown with reference to the schematic diagram of the configuration response message frame structure of fig. 6, the configuration response message frame may include a 2-handshake pilot sequence portion and an information data portion (i.e., configuration response information), wherein the information data portion indicates that the mobile station successfully received the configuration message frame.

As an example, the configuration response information may include the following: modulation symbol duration: 4 Ts; fixed symbol number: 15, the number of the cells is 15; fixed modulation coding level: BPSK uses cyclic error correction coding of 15 bits long and 5bits of valid data, where the 5bits information content is: data frame format number issued in configuration message frame: 3 bits; PAD: 2 bits.

Step 205, based on the configuration response message frame, adopting the target transmission branches to transmit data frames to the mobile station, respectively.

After receiving the configuration response message frame sent by the mobile station, the access point may assemble a data frame based on the configuration response message frame and send the data frame to the mobile station using the target transmission branch.

As an example, referring to fig. 7, a data frame structure diagram 1 shows that the data frame at least includes the following information: the mobile station may further include a handshake pilot part and a data part, wherein the pilot part may include a pilot symbol sequence and a second guard interval (GP), the data part may include a data symbol sequence and a second guard interval, and the data symbol sequence transmitted by each target transmission branch is space-time coded.

The purpose of GP is to protect the pilot sequence from interference from data of other transmit branches when a time offset occurs between transmit branches, and according to the data frame format of table 2, in one embodiment, the duration of GP is (Tf-Tp Np-Td Nd)/2.

The data portion may include a number of data symbols. In practice, if the data transmitted by each transmission branch is the same, the carrier frequency is the same between the transmission antennas, but the phases are random, and the time points of arrival at the mobile station are almost the same, so that energy is annihilated most probably due to the fact that the phases are opposite, for example, if the carrier phase at the time of transmission by the antenna 1 is 0 and the carrier phase by the antenna 2 is pi for X0, the signals transmitted by the antenna 1 and the antenna 2 are energy-cancelled at the receiving end. To overcome this problem, the transmit data may be cyclically shifted so that the same information elements are regularly spread out in time, thereby overcoming the energy cancellation problem.

In an embodiment, if the target transmission branch is 4, the data symbol sequence may adopt the following space-time coding scheme:

on transmit branch 1, transmit: x₀,X₁,X₂...,X_N-1；

On transmit branch 2, transmit: x_k1,X_k1+1,...X_N-1,X1,X2,...,X_k1-1；

On transmit branch 3, transmit: x_k2,X_k2+1,...X_N-1,X1,X2,...,X_k2-1；

On the transmission branch 4: x_k3,X_k3+1,...X_N-1,X1,X2,...,X_k3-1。

Where X represents a modulation symbol, e.g., for BPSK modulation, X represents +1 (corresponding to '1' before modulation) or-1 (corresponding to '0' before modulation), and for QPSK modulation, X represents

(corresponding to '00' before modulation),

(corresponding to the pre-modulation '01'),

(corresponding to '10' before modulation) or

(corresponding to the '11' before modulation); x_iIndicating a BPSK or QPSK modulation sequence to be transmitted, as an example but not limited thereto, N may be 24, k1 may be 6, k2 may be 12, and k3 may be 18.

For example, according to the BPSK example, assuming that N is 16, k1 is 4, k2 is 8, and k3 is 12, the following space-time coding scheme may be adopted for the 4 transmission branches:

the antenna 1 transmits: -1+1+1+1-1+1-1+1+1-1-1+1+1+1+1+1

The antenna 2 transmits: -1+1-1+1+1-1-1+1+1+1+1+1-1+1+1+1

The antenna 3 transmits: +1-1-1+1+1+1+1+1-1+1+1+1-1+1-1+1

The antenna 4 transmits: +1+1+1+1-1+1+1+1-1+1-1+1+1-1-1+1

In another embodiment, if the number of target transmission branches is 4, the data portion may further adopt the following space-time coding scheme:

on transmit branch 1, transmit: x₀,X₁,X₂...,X_N-1；

On transmit branch 2, transmit: x₀,X₁,X₂...,X_N-1Toeplitz (k 1); wherein, Toeplitz (k1) represents a Toeplitz matrix with N rows and N columns, the diagonal element corresponding to the element (k1,0) of the matrix is 1, the diagonal element corresponding to the element (0, (N-k1)) of the matrix is 1, and other elements are 0;

on transmit branch 3, transmit: x₀,X₁,X₂...,X_N-1Toeplitz (k 2); wherein Toeplitz (k2) represents a Toeplitz matrix with N rows and N columns, the diagonal element corresponding to the element (k2,0) of the matrix is 1, and the diagonal element corresponding to the element (0, (N-k2)) of the matrix is 1The line element is 1, and the other elements are 0;

on the transmission branch 4: x₀,X₁,X₂...,X_N-1Toeplitz (k 3); wherein, Toeplitz (k3) represents a Toeplitz matrix with N rows and N columns, the diagonal element corresponding to the element (k3,0) of the matrix is 1, the diagonal element corresponding to the element (0, (N-k3)) of the matrix is 1, and other elements are all 0.

For example, assume that N ═ 5, X₀,X₁,X₂...,X_N-1＝[-1，-1，+1，+1，+1]When k1 is equal to 2,

then X₀,X₁,X₂...,X_N-1*Toeplitz(k1)＝[+1，+1，+1，-1，-1]It can be seen that the shift is a loop left shift by k 1-2 bits.

It should be noted that, in addition to the above two space-time coding schemes, the two space-time coding schemes may also be applicable to coding of configuration signaling data of a configuration message frame, and those skilled in the art may adopt other space-time coding schemes, which is not limited in this embodiment of the present invention.

In a preferred embodiment of the present invention, step 205 may comprise the following sub-steps:

after the access point receives the configuration response message frame, assembling a data frame; converting the data frame into a data frame baseband signal; modulating the data frame baseband signal into a radio frequency signal; and sending the radio frequency signal after configuring a handshake frame duration of message frame start, wherein the handshake frame duration comprises the sum of the duration of the first handshake pilot frequency and the duration of the access time slot. .

Specifically, referring to fig. 8, a data frame structure diagram 2 shows that, after receiving a configuration response message frame sent by a mobile station, an access point assembles the data frame, performs root raised cosine transform on the data frame to convert the data frame into a data frame baseband signal, and sends the data frame baseband signal to a target sending branch, where the target sending branch modulates the baseband signal into a radio frequency signal, and continuously sends the data frame after configuring a handshake frame duration of the start of the message frame.

For the mobile station, after the mobile station sends the configuration response message frame to the access point, the data frame is continuously detected according to the time position of fig. 7, if the continuous Ndata data frames all detect errors, the mobile station re-detects the handshake frame, and continues the subsequent steps.

It should be noted that Ndata may be set according to actual needs, for example, Ndata may take a value of 4, and the embodiment of the present invention is not limited thereto.

In a specific implementation, for the case that there are 4 transmission branches of the access point, at the mobile station side, the data signal transmitted by the access point may be detected as follows:

the mobile station side carries out channel estimation on the 4 paths of transmission branches respectively and utilizes multi-branch joint reception. The algorithm of the joint reception may include, but is not limited to, a channel equalization algorithm, which may include zero forcing, a maximum likelihood algorithm, etc., and a decoding algorithm, which corresponds to an encoding algorithm, and the employed encoding method may include a cyclic code, a Turbo code, etc.

In one embodiment, a time-domain zero-forcing equalization scheme is as follows:

a) the channel estimation conditions for the multiple transmit branches are assumed to be known as follows:

the multipath channel estimate for transmit branch 1 is: ha₀,ha₁,ha₂...,ha_L1-1Branch 1 has L1 multipath taps;

the multipath channel estimate for transmit branch 2 is: hb (h)₀,hb₁,hb₂...,hb_L2-1Branch 1 has L2 multipath taps;

the multipath channel estimate for transmit branch 3 is: hc is₀,hc₁,hc₂...,hc_L3-1Branch 1 has L3 multipath taps;

the multipath channel estimate for the transmit branch 4 is: ha₀,ha₁,ha₂...,ha_L4-1Branch 1 has L4 multipath taps;

the description of the multipath tap corresponding to the channel impulse response means that the channel has 4 multipaths.

The mobile station is arranged to remove the modulation carrier of the received short wave radio frequency signal and filter the short wave radio frequency signal to obtain a baseband signal r₀,r₁,r₂...,r_N-1And r is a baseband signal obtained by removing the modulation carrier from the received short-wave radio frequency signal and root-raised cosine filtering, and is a complex sequence.

b) The channel tap models for the 4 transmit branches are calculated:

specifically, the matrix entries of branch 2 may be arranged in the form:

wherein the content of the first and second substances,

is to

The N row vectors are circularly shifted down by k1 times, and then the N column vectors are circularly shifted right by k1 times.

Similarly, the matrix entries for branch 3 and branch 4 may be organized as follows:

is to

The N row vectors are circularly shifted down by k2 times, and then the N column vectors are circularly shifted right by k2 times.

Is to

The N row vectors are circularly shifted down by k3 times, and then the N column vectors are circularly shifted right by k3 times.

By working up equation (i), we can obtain:

wherein the content of the first and second substances,

according to a zero-forcing equalization algorithm:

in another implementation, if in the aforementioned Toeplitz matrix form, the above b) step can be written as:

then the above formula can be collated:

according to the zero-forcing equalization algorithm, the following can be obtained:

wherein the content of the first and second substances,

the embodiment of the invention provides a signal processing method based on short-wave wide-area diversity, which can solve the problem of poor communication performance of a short-wave sky-wave transmission system based on ionospheric reflection, solve the problem of deep fading of a short-wave channel by utilizing multi-path transmission branch transmission of wide-area distribution, improve the channel adaptability of the short-wave system and further improve the communication performance.

Furthermore, the embodiment of the invention ensures that the frame lengths of the sending branches are the same by coordinating the frame lengths of the sending branches, thereby meeting the requirements of the relevant time of the sending branches; the pilot frequency length of each sending branch is ensured to be the same by coordinating the pilot frequency length when the multiple sending branches are transmitted, thereby meeting the pilot frequency signal quality requirement of each sending branch, reducing the interference among the branches and simplifying the signal processing of a receiver.

Referring to fig. 9, a flowchart illustrating steps of another embodiment of a signal processing method according to the present invention is shown, where the embodiment of the present invention is described from a mobile station side, and specifically includes the following steps:

step 901, when handshake frames sent by a plurality of transmission branches are received, obtaining measurement information corresponding to channels between the transmission branches and the mobile station, respectively, where the transmission branches are wide area deployed transmission branches;

step 902, organizing the measurement information into a measurement information frame, and returning the measurement information frame to an access point;

step 903, receiving a configuration message frame sent by a plurality of target sending branches, where the target sending branches are sending branches selected by an access point from the plurality of sending branches based on the measurement information frame, and the number of the sending branches is within a first interval range;

step 904, based on the configuration message frame, returning a corresponding configuration response message frame to the access point;

step 905, receiving the data frames sent by the multiple target sending branches.

In a preferred embodiment of the present invention, the handshake frame may include a first handshake pilot and an access slot, where the first handshake pilot of each candidate transmission branch includes a pseudorandom sequence with equal length, and the pseudorandom sequence is formed by cyclic shifting a same base sequence; and the mobile station sends a measurement information frame to an access point by adopting the access time slot.

In a preferred embodiment of the present invention, the measurement information frame may include a second handshake pilot and measurement information;

the second handshake pilot frequency is a pseudorandom sequence;

the measurement information at least includes: validity of each candidate transmission branch, number of the latest arriving candidate transmission branch, channel information of each candidate transmission branch and delay information of each valid candidate transmission branch; wherein the channel information at least comprises a frequency offset value and an amplitude peak-to-average ratio of a correlation peak.

In a preferred embodiment of the present invention, step 901 may include the following sub-steps:

a substep S31 of detecting a first handshake pilot from the received signal;

and a substep S32, measuring the channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot, and obtaining the measurement information of the channel.

In a preferred embodiment of the present invention, the sub-step S31 may include the following sub-steps:

substep S311, taking a signal with a first preset threshold duration from the received signal, and sliding with the first preset threshold as a step length;

in sub-step S312, when the signal obtained after the sliding includes the non-handshake pilot signal, the sliding continues with the first preset threshold as the step length until the signal obtained after the sliding only includes the signal of the first handshake pilot, and it is determined that the first handshake pilot is detected.

In a preferred embodiment of the present invention, the sub-step S32 may include the following sub-steps:

substep S321, converting the pseudo-random sequence of the first handshake pilot frequency into a frequency domain sequence;

substep S322, acquiring a radio frequency signal from an air interface, converting the radio frequency signal into a baseband signal according to a specified frequency offset value, and converting the baseband signal into a frequency domain signal, wherein the specified frequency offset value is selected from a preset frequency offset value range;

substep S323, calculating a channel estimation vector based on the frequency domain signal and the frequency domain sequence;

substep S324, traversing the frequency offset values in the frequency offset value range to obtain a plurality of channel estimation vectors;

substep S325, obtaining an average value of the amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and recording the average value as an amplitude average value;

substep S326, obtaining a maximum value of an amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and recording the maximum value as an amplitude peak value;

substep S327, calculating a ratio of the amplitude peak value to the amplitude mean value for each channel estimation vector of the plurality of channel estimation vectors to obtain an amplitude peak-to-mean ratio;

substep S328, selecting a channel estimation vector with the largest amplitude peak-to-average ratio from the plurality of channel estimation vectors, recording the channel estimation vector as the largest amplitude peak-to-average ratio, and recording a frequency offset value corresponding to the largest amplitude peak-to-average ratio;

substep S328, determining that the candidate transmission branch is invalid if the maximum amplitude peak-to-average ratio is smaller than a second preset threshold; and if the maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold value, judging that the candidate sending branch is effective.

In a preferred embodiment of the present invention, the sub-step S32 may further include the following sub-steps:

substep S41, when determining that the candidate transmission branch is invalid, sliding by taking a third preset threshold as a step size, and continuing to execute substep S322-substep S328;

substep S42, when the candidate transmission branch is determined to be valid, performing windowing at the position of the next first handshake pilot of the candidate transmission branch, and continuing to execute substeps S322-S327 to obtain a new maximum amplitude peak-to-average ratio; recording a subscript value of a channel estimation vector corresponding to the new maximum amplitude peak-to-average ratio, and if the subscript value is smaller than a preset oversampling multiple and the new maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold, determining that the candidate transmission branch is valid; and if the subscript value is greater than or equal to a preset oversampling multiple and/or the new maximum amplitude peak-to-average ratio is less than a second preset threshold, determining that the candidate transmission branch is invalid.

In a preferred embodiment of the present invention, the sub-step S32 may further include the following sub-steps:

when a preset timer in a mobile station is overtime, determining effective candidate transmitting branches from the candidate transmitting branches;

respectively acquiring the absolute time of the frame headers of the handshake frames of the effective candidate sending branches;

selecting the candidate transmission branch with the maximum absolute time from the effective candidate transmission branches as the latest arrival transmission branch;

and calculating the difference value between the absolute time of other candidate transmission branches and the absolute time of the latest arriving transmission branch as the time delay information of other transmission branches.

In a preferred embodiment of the present invention, before step 903, the method further includes the following steps:

receiving handshake frames sent by the target sending branches;

measuring a channel between the corresponding target transmission branch and the mobile station based on the handshake frame to obtain corresponding measurement information;

organizing the measurement information corresponding to the target transmission branches into a measurement information frame, and returning the measurement information frame to the access point.

In a preferred embodiment of the present invention, the configuration message frame at least includes the following information: the method comprises the steps of a first handshake pilot frequency, a first protection interval and configuration signaling data, wherein the configuration signaling data has a fixed symbol number, a fixed modulation symbol duration and a fixed modulation coding grade; and the configuration signaling data sent by each target sending branch adopts a space-time coding mode.

In a preferred embodiment of the present invention, the configuration response message frame at least includes the following information: a third handshake pilot and configuration response information, wherein the configuration response information is used for indicating that the mobile station successfully receives the configuration message frame.

In a preferred embodiment of the present invention, the data frame at least includes the following information: the pilot part comprises a pilot sequence and a second guard interval, the data part comprises a data symbol sequence and a second guard interval, and the data symbol sequence transmitted by each target transmission branch adopts a space-time coding mode.

As for the method embodiment of fig. 9, since it is basically similar to the method embodiment of fig. 2, the description is simple, and the relevant points can be referred to the partial description of the method embodiment.

It should be noted that, for simplicity of description, the method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present invention is not limited by the illustrated order of acts, as some steps may occur in other orders or concurrently in accordance with the embodiments of the present invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.

Referring to fig. 10, a block diagram of an access point according to an embodiment of the present invention is shown, which may specifically include the following modules:

a measurement information obtaining module 1001 configured to obtain measurement information corresponding to each of a plurality of transmission branches deployed in a wide area;

a target transmission branch selecting module 1002, configured to select a target transmission branch from the multiple transmission branches based on the measurement information, where the number of the target transmission branches is within a first interval range;

a configuration message frame sending module 1003, configured to send configuration message frames to the mobile stations by using the target sending branches, respectively;

a configuration response message frame receiving module 1004, configured to receive a configuration response message frame corresponding to the configuration message frame returned by the mobile station;

a data frame sending module 1005, configured to send data frames to the mobile stations by using the target sending branches respectively based on the configuration response message frame.

In a preferred embodiment of the present invention, the measurement information obtaining module 1001 may include the following sub-modules:

a candidate branch selection sub-module, configured to select a candidate transmission branch from the plurality of transmission branches, where the number of candidate transmission branches is within a second interval range;

a handshake frame sending submodule, configured to send handshake frames to the mobile station at the same frequency by using the candidate sending branches, respectively;

a measurement information frame receiving submodule, configured to receive a measurement information frame returned by the mobile station based on the handshake frame, and obtain measurement information corresponding to the candidate transmission branches based on the measurement information frame, respectively, where the measurement information is obtained after the mobile station measures a channel between the corresponding candidate transmission branch and the mobile station based on the handshake frame;

and the continuous judgment submodule is used for calling the candidate branch selection submodule if the unselected sending branches exist in the sending branches until all the sending branches are measured. In a preferred embodiment of the embodiments of the present invention, the handshake frame includes a first handshake pilot and an access slot, where the first handshake pilot of each candidate transmission branch includes a pseudorandom sequence with equal length, the pseudorandom sequence is formed by cyclic shifting a same basic sequence, and the access slot is used for placing measurement information sent by the mobile station to the access point.

In a preferred embodiment of the present invention, the measurement information includes a second handshake pilot and measurement information;

the second handshake pilot frequency is a pseudorandom sequence;

the measurement information at least includes: validity of each candidate transmission branch, number of the latest arriving candidate transmission branch, channel information corresponding to each candidate transmission branch and delay information of each valid candidate transmission branch; wherein the content of the first and second substances,

the channel information at least comprises a frequency offset value and an amplitude peak-to-average ratio of a correlation peak;

the delay information is based on the absolute time of the frame headers of the handshake frames of the candidate sending branch arriving at the latest, and the time difference between the absolute time of the frame headers of the handshake frames of other effective candidate sending branches and the absolute time of the candidate sending branch arriving at the latest.

In a preferred embodiment of the present invention, the data frame at least includes the following information: the pilot part comprises a pilot symbol sequence and a second guard interval, the data part comprises a data symbol sequence and a second guard interval, and the data symbol sequence transmitted by each target transmission branch adopts a space-time coding mode.

In a preferred embodiment of the present invention, the target transmission branch selecting module 1002 may include the following sub-modules:

an effective branch determining sub-module, configured to select an effective transmission branch from the multiple transmission branches based on measurement information corresponding to each transmission branch if the multiple transmission branches are measured;

the first set determining submodule is used for dividing the effective sending branches into two first sets according to the comparison result of the amplitude peak-to-average ratio and a fourth preset threshold;

a second set determining submodule, configured to divide the effective transmission branches into four second sets according to the frequency offset value;

the intersection operation sub-module is used for respectively carrying out intersection operation on the first set and the second set to form a plurality of intersection sets;

the union set operation sub-module is used for respectively carrying out union set operation on the intersection sets to form union set sets;

a selection order determining submodule, configured to determine a selection order of the intersection set and/or the union set according to the amplitude peak-to-average ratio and the frequency offset value, and sort sets with larger amplitude peak-to-average ratios and/or smaller frequency offset values in the selection order;

a target branch determining submodule, configured to select, according to the selection order, the upper-limit sending branches of the first interval range from the corresponding intersection combinations and/or the union set as target sending branches, where a sending branch is randomly selected for each intersection combination;

and the adjusting submodule is used for subtracting 1 from the upper limit of the first interval and calling the target branch determining submodule if the number of the target sending branches is less than the upper limit of the first interval.

In a preferred embodiment of the present invention, the following modules may be further included:

a data frame format determining module, configured to determine a data frame format of the target transmission branch, where the data frame format at least includes: the total time length of the data frame, the time length of the pilot symbols and the number of the pilot symbols of the data frame, the time length of the data symbols and the number of the data symbols, the modulation mode and the air interface rate.

In a preferred embodiment of the present invention, the following modules may be further included:

target branch information sending module, which is used to send handshake frame to mobile station with same frequency by using the target sending branch;

and the target branch information receiving module is used for receiving the measurement information frame which is returned by the mobile station and corresponds to the handshake frame.

In a preferred embodiment of the present invention, the configuration message frame sending module 1003 may include the following sub-modules:

a delay information obtaining submodule, configured to obtain delay information indicated in measurement information corresponding to the target transmission branch;

and the delay sending submodule is used for delaying and sending the configuration message frame of the corresponding sending branch based on the time delay information, wherein the signal frequency of the configuration message frame sent by each target sending branch is the same.

In a preferred embodiment of the present invention, the following modules may be further included:

a timer starting module, configured to start a timer after sending the configuration message frame;

a retransmission module, configured to send the configuration message frame to the mobile station by using the target transmission branch again if the configuration response message frame is not received when the timer times out;

and the branch re-determination module is used for calling the candidate branch selection submodule to re-determine the target transmission branch if the configuration response message frame is not received when the number of times of the transmitted configuration message frame is greater than a preset number threshold.

In a preferred embodiment of the present invention, the configuration message frame at least includes the following information: the method comprises the steps of a first handshake pilot frequency, a first protection interval and configuration signaling data, wherein the configuration signaling data has a fixed symbol number, a fixed modulation symbol duration and a fixed modulation coding grade; and the configuration signaling data sent by each target sending branch adopts a space-time coding mode.

In a preferred embodiment of the present invention, the configuration response message frame at least includes the following information: a third handshake pilot frequency and configuration response information, wherein the third handshake pilot frequency is a pseudo-random sequence; the configuration response information is used to indicate that the mobile station successfully received the configuration message frame.

In a preferred embodiment of the present invention, the data frame sending module 1005 may include the following sub-modules:

the data frame assembling sub-module is used for assembling the data frame after the access point receives the configuration response message frame;

the signal conversion sub-module is used for converting the data frame into a data frame baseband signal; modulating the data frame baseband signal into a radio frequency signal;

and the signal sending submodule is used for sending the radio-frequency signal after the handshake frame duration corresponding to the configuration message frame, wherein the handshake frame duration comprises the sum of the duration of the first handshake pilot frequency and the duration of the access time slot.

Referring to fig. 11, a block diagram of a mobile station of an embodiment of the present invention is shown, which may specifically include the following modules:

a measurement information obtaining module 1101, configured to obtain measurement information corresponding to channels between a plurality of transmission branches and the mobile station when handshake frames sent by the transmission branches are received, where the transmission branches are wide-area deployed transmission branches;

a measurement information frame sending module 1102, configured to organize the measurement information into a measurement information frame, and return the measurement information frame to an access point;

a configuration message frame receiving module 1103, configured to receive a configuration message frame sent by a plurality of target sending branches, where the target sending branches are sending branches that are selected by an access point based on the measurement information frame and whose number is within a first interval range from the plurality of sending branches;

a configuration response message frame sending module 1104, configured to return a corresponding configuration response message frame to the access point based on the configuration message frame;

a data frame receiving module 1105, configured to receive the data frames sent by the multiple target sending branches.

In a preferred embodiment of the present invention, the handshake frame includes a first handshake pilot and an access slot, where the first handshake pilot of each candidate transmission branch includes pseudorandom sequences with equal length, and the pseudorandom sequences are formed by cyclic shifting the same base sequence; and the mobile station sends a measurement information frame to an access point by adopting the access time slot.

In a preferred embodiment of the present invention, the measurement information frame includes a second handshake pilot and measurement information;

the second handshake pilot frequency is a pseudorandom sequence;

the measurement information at least includes: validity of each candidate transmission branch, number of the latest arriving candidate transmission branch, channel information of each candidate transmission branch and delay information of each valid candidate transmission branch; wherein the content of the first and second substances,

the channel information at least comprises a frequency offset value and an amplitude peak-to-average ratio of a correlation peak.

In a preferred embodiment of the present invention, the measurement information obtaining module 1101 may include the following sub-modules:

a pilot detection sub-module for detecting a first handshake pilot from the received signal;

and the measuring submodule is used for measuring the channel between the corresponding candidate sending branch and the mobile station based on the first handshake pilot frequency to obtain the measuring information of the channel.

In a preferred embodiment of the present invention, the pilot detection sub-module includes the following units:

the window taking unit is used for taking a signal with a first preset threshold duration from the received signal and sliding by taking the first preset threshold as a step length;

and the first sliding unit is used for continuing sliding by taking a first preset threshold value as a step length when the signals obtained after sliding contain non-handshake pilot signals, and judging that the first handshake pilot is detected until the signals obtained after sliding only contain signals of the first handshake pilot.

In a preferred embodiment of the present invention, the measurement submodule includes the following units:

a first frequency domain converting unit, configured to convert the pseudo-random sequence of the first handshake pilot into a frequency domain sequence;

the second frequency domain conversion unit is used for acquiring a radio frequency signal from an air interface, converting the radio frequency signal into a baseband signal according to a specified frequency offset value, and converting the baseband signal into a frequency domain signal, wherein the specified frequency offset value is selected from a preset frequency offset value range;

a correlation unit, configured to calculate a channel estimation vector based on the frequency domain signal and the frequency domain sequence;

the convergence unit is used for traversing the frequency offset value in the frequency offset value range to obtain a plurality of channel estimation vectors;

an amplitude mean value obtaining unit, configured to obtain an average value of amplitude absolute values of each of the plurality of channel estimation vectors, and record the average value as an amplitude mean value;

an amplitude peak value obtaining unit, configured to obtain a maximum value of an amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and record the maximum value as an amplitude peak value;

the amplitude peak-to-average ratio calculation unit is used for calculating the ratio of the amplitude peak value to the amplitude average value aiming at each channel estimation vector in the plurality of channel estimation vectors to obtain an amplitude peak-to-average ratio;

the amplitude peak determining unit is used for selecting the channel estimation vector with the maximum amplitude peak-to-average ratio from the plurality of channel estimation vectors, recording the channel estimation vector as the maximum amplitude peak-to-average ratio and recording a frequency offset value corresponding to the maximum amplitude peak-to-average ratio;

the judging unit is used for judging that the candidate sending branch is invalid if the maximum amplitude peak-to-average ratio is smaller than a second preset threshold; and if the maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold value, judging that the candidate sending branch is effective.

In a preferred embodiment of the present invention, the measurement sub-module further includes the following units:

a second sliding unit, configured to slide by using a third preset threshold as a step length and call the second frequency domain converting unit when it is determined that the candidate transmission branch is invalid;

a recording unit, configured to perform windowing at a position of a next first handshake pilot of the candidate transmission branch when it is determined that the candidate transmission branch is valid, and call the second frequency domain converting unit to obtain a new maximum amplitude peak-to-average ratio; recording a subscript value of a channel estimation vector corresponding to the new maximum amplitude peak-to-average ratio, and if the subscript value is smaller than a preset oversampling multiple and the new maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold, determining that the candidate transmission branch is valid; and if the subscript value is greater than or equal to a preset oversampling multiple and/or the new maximum amplitude peak-to-average ratio is less than a second preset threshold, determining that the candidate transmission branch is invalid.

In a preferred embodiment of the present invention, the measurement sub-module further includes the following units:

an effective branch determining unit, configured to determine an effective candidate transmission branch from the candidate transmission branches when a timer preset in the mobile station expires;

an absolute time obtaining unit, configured to obtain absolute times of frame headers of handshake frames of the valid candidate transmission branches, respectively;

a latest arrival branch determination unit configured to select, from the valid candidate transmission branches, a candidate transmission branch whose absolute time is the largest as a latest arrival transmission branch;

and the delay information calculation unit is used for calculating the difference value between the absolute time of other candidate transmission branches and the absolute time of the latest arriving transmission branch as the delay information of other transmission branches.

In a preferred embodiment of the present invention, the mobile station further includes the following modules:

a handshake frame receiving module, configured to receive handshake frames sent by the multiple target sending branches;

a measurement information obtaining module, configured to measure a channel between a corresponding target transmission branch and a mobile station based on the handshake frame, and obtain corresponding measurement information;

and the measurement information frame sending module is used for organizing the measurement information corresponding to the target sending branches into a measurement information frame and returning the measurement information frame to the access point.

In a preferred embodiment of the present invention, the configuration message frame at least includes the following information: the method comprises the steps of a first handshake pilot frequency, a first protection interval and configuration signaling data, wherein the configuration signaling data has a fixed symbol number, a fixed modulation symbol duration and a fixed modulation coding grade; and the configuration signaling data sent by each target sending branch adopts a space-time coding mode.

In a preferred embodiment of the present invention, the configuration response message frame at least includes the following information: a third handshake pilot frequency and configuration response information, wherein the third handshake pilot frequency is a pseudo-random sequence; the configuration response information is used to indicate that the mobile station successfully received the configuration message frame.

In a preferred embodiment of the present invention, the data frame at least includes the following information: the pilot part comprises a pilot sequence and a second guard interval, the data part comprises a data symbol sequence and a second guard interval, and the data symbol sequence transmitted by each target transmission branch adopts a space-time coding mode.

For the access point embodiment and the mobile station embodiment, since they are basically similar to the method embodiment, the description is simple, and for the relevant points, refer to the partial description of the method embodiment.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, access point, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

The foregoing detailed description of a signal processing method, system, access point and mobile station provided by the present invention has been provided, and the present invention provides a specific example to explain the principle and the implementation of the present invention, and the description of the above embodiment is only used to help understand the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the service scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims (27)

1. A signal processing method applied to an access point side, the method comprising:

acquiring measurement information corresponding to each transmission branch in a plurality of transmission branches deployed in a wide area;

selecting a target transmission branch from the plurality of transmission branches based on the measurement information, wherein the number of the target transmission branches is within a first interval range;

respectively adopting the target transmission branches to transmit configuration message frames to the mobile station;

receiving a configuration response message frame which is returned by the mobile station and corresponds to the configuration message frame;

respectively adopting the target transmission branches to transmit data frames to the mobile station based on the configuration response message frame;

wherein the step of sending a configuration message frame to a mobile station using the target transmission branches respectively comprises:

acquiring time delay information indicated in the measurement information corresponding to the target transmission branch;

and based on the time delay information, delaying to send a configuration message frame corresponding to the sending branch, wherein the signal frequency of the configuration message frame sent by each target sending branch is the same.

2. The method of claim 1, wherein the step of obtaining measurement information corresponding to each of a plurality of transmission branches of a wide-area deployment comprises:

selecting a candidate transmission branch from the plurality of transmission branches, wherein the number of the candidate transmission branches is within a second interval range;

respectively adopting the candidate transmitting branches to transmit handshake frames to the mobile station at the same frequency;

receiving a measurement information frame returned by the mobile station based on the handshake frame, and respectively acquiring measurement information corresponding to the candidate transmission branches based on the measurement information frame, wherein the measurement information is obtained after the mobile station measures a channel between the candidate transmission branches and the mobile station based on the handshake frame;

if there are still unselected transmission branches in the transmission branches, the step of selecting candidate transmission branches from the plurality of transmission branches is continuously executed until all transmission branches are measured.

3. The method of claim 2, wherein the handshake frame comprises a first handshake pilot and an access slot, wherein the first handshake pilot of each candidate transmission branch comprises a pseudo-random sequence with equal length, the pseudo-random sequence is formed by cyclic shifting a same basic sequence, and the access slot is used for placing a measurement information frame transmitted by the mobile station to the access point.

4. The method of claim 3, wherein the measurement information frame comprises a second handshake pilot and measurement information;

the second handshake pilot frequency is a pseudorandom sequence;

the measurement information at least includes: validity of each candidate transmission branch, number of the latest arriving candidate transmission branch, channel information corresponding to each candidate transmission branch and delay information of each valid candidate transmission branch; wherein the content of the first and second substances,

the channel information at least comprises a frequency offset value and an amplitude peak-to-average ratio of a correlation peak;

the delay information is based on the absolute time of the frame headers of the handshake frames of the candidate sending branch arriving at the latest, and the time difference between the absolute time of the frame headers of the handshake frames of other effective candidate sending branches and the absolute time of the candidate sending branch arriving at the latest.

5. The method according to any of claims 1-4, wherein the data frame comprises at least the following information: the pilot part comprises a pilot symbol sequence and a second guard interval, the data part comprises a data symbol sequence and a second guard interval, and the data symbol sequence transmitted by each target transmission branch adopts a space-time coding mode.

6. The method of claim 4, wherein the step of selecting a target transmission branch from the plurality of transmission branches based on the measurement information comprises:

if the plurality of transmission branches are measured, selecting an effective transmission branch from the plurality of transmission branches based on the measurement information corresponding to each transmission branch;

dividing the effective sending branches into two first sets according to the comparison result of the amplitude peak-to-average ratio and a fourth preset threshold;

dividing the effective transmission branches into four second sets according to the frequency offset value;

performing intersection operation on the first set and the second set respectively to form a plurality of intersection sets;

performing union operation on the intersection sets respectively to form union sets;

determining the selection order of the intersection set and/or the union set according to the amplitude peak-to-average ratio and the frequency deviation value, and ordering the sets with larger amplitude peak-to-average ratio and/or smaller frequency deviation value in the selection order;

according to the selection sequence, respectively selecting the upper limit sending branches of the first interval from the corresponding intersection combination and/or union set as target sending branches, wherein the sending branches are randomly selected for each intersection set;

and if the number of the target sending branches is less than the upper limit of the first interval, subtracting 1 from the upper limit of the first interval, and continuing to execute the step of selecting the upper limit sending branches of the first interval from the corresponding intersection combination and/or union set as the target sending branches according to the selection order.

7. The method of claim 6, further comprising:

determining a data frame format of the target transmission branch, wherein the data frame format at least comprises: the total time length of the data frame, the time length of the pilot symbols and the number of the pilot symbols of the data frame, the time length of the data symbols and the number of the data symbols, the modulation mode and the air interface rate.

8. The method of claim 1, further comprising, prior to the step of sending configuration message frames to mobile stations using the target transmission branch, respectively:

respectively adopting the target transmission branches to transmit handshake frames to the mobile station at the same frequency;

and receiving a measurement information frame corresponding to the handshake frame and returned by the mobile station.

9. The method according to claim 1, further comprising, before the step of receiving a configuration response message frame corresponding to the configuration message frame returned by the mobile station:

starting a timer after the configuration message frame is sent;

if the timer is overtime and does not receive a configuration response message frame, the target transmission branch is adopted again to transmit the configuration message frame to the mobile station;

and when the number of times of sending the configuration message frame is greater than a preset number threshold, if the configuration response message frame is not received, re-executing the step of selecting the candidate sending branch from the plurality of sending branches to re-determine the target sending branch.

10. The method of claim 1, wherein the configuration message frame comprises at least the following information: the method comprises the steps of a first handshake pilot frequency, a first protection interval and configuration signaling data, wherein the configuration signaling data has a fixed symbol number, a fixed modulation symbol duration and a fixed modulation coding grade; and the configuration signaling data sent by each target sending branch adopts a space-time coding mode.

11. The method of claim 10, wherein the configuration response message frame comprises at least the following information: a third handshake pilot frequency and configuration response information, wherein the third handshake pilot frequency is a pseudo-random sequence; the configuration response information is used to indicate that the mobile station successfully received the configuration message frame.

12. The method of claim 3, wherein the step of sending data frames to the mobile stations using the corresponding target transmission branches respectively based on the configuration response message frame comprises:

after the access point receives the configuration response message frame, assembling a data frame;

converting the data frame into a data frame baseband signal;

modulating the data frame baseband signal into a radio frequency signal;

and sending the radio frequency signal after a handshake frame duration corresponding to the configuration message frame, wherein the handshake frame duration comprises the sum of the duration of the first handshake pilot frequency and the duration of the access time slot.

13. A signal processing method applied to a mobile station side, the method comprising:

when handshake frames sent by a plurality of sending branches are received, measuring information corresponding to channels between the sending branches and the mobile station is respectively obtained, wherein the sending branches are wide-area deployed sending branches;

organizing the measurement information into a measurement information frame, and returning the measurement information frame to an access point;

receiving a configuration message frame sent by a plurality of target transmission branches, wherein the target transmission branches are transmission branches which are selected by an access point based on the measurement information frame and the number of which is within a first interval range from the plurality of transmission branches;

returning a corresponding configuration response message frame to the access point based on the configuration message frame;

receiving data frames transmitted by the target transmission branches;

wherein, the step of receiving the configuration message frame sent by the plurality of target sending branches comprises:

and receiving the configuration message frame which is transmitted by the target transmission branch based on the acquired time delay information indicated in the corresponding measurement information.

14. The method of claim 13, wherein the handshake frame comprises a first handshake pilot and an access slot, wherein the first handshake pilot of each candidate transmission branch comprises a pseudo-random sequence with equal length, and wherein the pseudo-random sequence is formed by cyclic shifting a same base sequence; and the mobile station sends a measurement information frame to an access point by adopting the access time slot.

15. The method of claim 14, wherein the measurement information frame comprises a second handshake pilot and measurement information;

the second handshake pilot frequency is a pseudorandom sequence;

the measurement information at least includes: validity of each candidate transmission branch, number of the latest arriving candidate transmission branch, channel information of each candidate transmission branch and delay information of each valid candidate transmission branch; wherein the content of the first and second substances,

the channel information at least comprises a frequency offset value and an amplitude peak-to-average ratio of a correlation peak.

16. The method according to claim 15, wherein the step of respectively obtaining the measurement information corresponding to the channels between the transmission branches and the mobile stations when receiving the handshake frames transmitted by multiple transmission branches comprises:

detecting a first handshake pilot from a received signal;

and measuring the channel between the corresponding candidate sending branch and the mobile station based on the first handshake pilot frequency to obtain the measurement information of the channel.

17. The method of claim 16, wherein the step of detecting the first handshake pilot from the received signal comprises:

taking a signal with a first preset threshold duration from the received signal, and sliding by taking the first preset threshold as a step length;

and when the signals obtained after sliding comprise non-handshake pilot signals, continuing sliding by taking a first preset threshold as a step length until the signals obtained after sliding only comprise signals of the first handshake pilot, and determining that the first handshake pilot is detected.

18. The method of claim 17, wherein the step of measuring the channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot to obtain the measurement information of the channel comprises:

converting the pseudo-random sequence of the first handshake pilot into a frequency domain sequence;

acquiring a radio frequency signal from an air interface, converting the radio frequency signal into a baseband signal according to a specified frequency offset value, and converting the baseband signal into a frequency domain signal, wherein the specified frequency offset value is selected from a preset frequency offset value range;

calculating a channel estimation vector based on the frequency domain signal and the frequency domain sequence;

traversing the frequency offset values in the frequency offset value range to obtain a plurality of channel estimation vectors;

obtaining the average value of the amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and recording the average value as an amplitude average value;

obtaining the maximum value of the amplitude absolute value of each channel estimation vector in the plurality of channel estimation vectors, and recording the maximum value as an amplitude peak value;

calculating the ratio of the amplitude peak value to the amplitude mean value aiming at each channel estimation vector in the plurality of channel estimation vectors to obtain an amplitude peak-to-mean ratio;

selecting a channel estimation vector with the maximum amplitude peak-to-average ratio from the plurality of channel estimation vectors, recording the channel estimation vector as the maximum amplitude peak-to-average ratio, and recording a frequency offset value corresponding to the maximum amplitude peak-to-average ratio;

if the maximum amplitude peak-to-average ratio is smaller than a second preset threshold value, judging that the candidate sending branch is invalid;

and if the maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold value, judging that the candidate sending branch is effective.

19. The method of claim 18, wherein the step of measuring the channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot to obtain the measurement information of the channel further comprises:

when the candidate sending branch is judged to be invalid, sliding by taking a third preset threshold as a step length, returning to the slave air interface to acquire a radio frequency signal, converting the radio frequency signal into a baseband signal according to a preset frequency offset value, and converting the baseband signal into a frequency domain signal;

when the candidate sending branch is judged to be effective, performing window taking at the position of the next first handshake pilot frequency of the candidate sending branch, returning to continue executing the steps of obtaining a radio frequency signal from an air interface, converting the radio frequency signal into a baseband signal according to a preset frequency offset value, and converting the baseband signal into a frequency domain signal so as to obtain a new maximum amplitude peak-to-average ratio; recording a subscript value of a channel estimation vector corresponding to the new maximum amplitude peak-to-average ratio, and if the subscript value is smaller than a preset oversampling multiple and the new maximum amplitude peak-to-average ratio is larger than or equal to a second preset threshold, determining that the candidate transmission branch is valid; and if the subscript value is greater than or equal to a preset oversampling multiple and/or the new maximum amplitude peak-to-average ratio is less than a second preset threshold, determining that the candidate transmission branch is invalid.

20. The method according to claim 18 or 19, wherein the step of measuring the channel between the corresponding candidate transmission branch and the mobile station based on the first handshake pilot to obtain the measurement information of the channel further comprises:

when a preset timer in a mobile station is overtime, determining effective candidate transmitting branches from the candidate transmitting branches;

respectively acquiring the absolute time of the frame headers of the handshake frames of the effective candidate sending branches;

selecting the candidate transmission branch with the maximum absolute time from the effective candidate transmission branches as the latest arrival transmission branch;

and calculating the difference value between the absolute time of other candidate transmission branches and the absolute time of the latest arriving transmission branch as the time delay information of other transmission branches.

21. The method of claim 13, wherein before the step of receiving the configuration message frame sent by the plurality of target transmission branches, the method further comprises:

receiving handshake frames sent by the target sending branches;

measuring a channel between the corresponding target transmission branch and the mobile station based on the handshake frame to obtain corresponding measurement information;

organizing the measurement information corresponding to the target transmission branches into a measurement information frame, and returning the measurement information frame to the access point.

22. The method of claim 13, wherein the configuration message frame comprises at least the following information: the method comprises the steps of a first handshake pilot frequency, a first protection interval and configuration signaling data, wherein the configuration signaling data has a fixed symbol number, a fixed modulation symbol duration and a fixed modulation coding grade; and the configuration signaling data sent by each target sending branch adopts a space-time coding mode.

23. The method of claim 13, wherein the configuration response message frame comprises at least the following information: a third handshake pilot frequency and configuration response information, wherein the third handshake pilot frequency is a pseudo-random sequence; the configuration response information is used to indicate that the mobile station successfully received the configuration message frame.

24. The method of claim 13, wherein the data frame comprises at least the following information: the pilot part comprises a pilot symbol sequence and a second guard interval, the data part comprises a data symbol sequence and a second guard interval, and the data symbol sequence transmitted by each target transmission branch adopts a space-time coding mode.

25. A signal processing system comprises an access point and a mobile station, and is characterized in that the access point comprises an indoor unit, a plurality of outdoor units deployed in a wide area, short wave antennas and a synchronous digital hierarchy optical ring network, wherein each outdoor unit is connected with one set of short wave antenna through a radio frequency feeder line, and is connected to the indoor unit through the synchronous digital hierarchy optical ring network;

the indoor unit is used for selecting candidate outdoor units from the outdoor units, assembling handshake frames aiming at the candidate outdoor units, sending the handshake frames to the corresponding candidate outdoor units in a baseband signal mode, selecting target outdoor units from the outdoor units based on the measurement information frames after receiving the measurement information frames sent by the candidate outdoor units, assembling configuration information frames to be sent to the target outdoor units, and assembling data frames to be sent to the target outdoor units after receiving configuration response information frames sent by the target outdoor units;

the outdoor unit is used for sending the handshake frame to the mobile station in the form of short-wave frequency band radio frequency signals, sending the measurement information frame to the indoor unit when receiving the measurement information frame returned by the mobile station based on the handshake frame, sending the configuration message frame to the mobile station after receiving the configuration message frame sent by the indoor unit, sending the configuration response message frame to the indoor unit after receiving the configuration response message frame returned by the mobile station based on the configuration message frame, and sending the received data frame sent by the indoor unit to the mobile station;

the mobile station is used for measuring channels between the candidate outdoor unit and the mobile station based on the handshake frame to obtain corresponding measurement information, assembling the measurement information into a measurement information frame and sending the measurement information frame to the candidate outdoor unit, returning a corresponding configuration response message frame to the target outdoor unit after receiving a configuration message frame sent by the target outdoor unit, and receiving a data frame sent by the target outdoor unit;

wherein the transmitting the configuration message frame to the mobile station after receiving the configuration message frame transmitted by the indoor unit comprises:

the indoor unit indicates the transmitted time delay information to the target outdoor unit corresponding to each diversity transmission branch according to the measurement information,

according to the corresponding time delay information, delaying to send the configuration message frame to the mobile station; wherein the signal frequency of the configuration message frame transmitted by each target outdoor unit is the same.

26. An access point, comprising:

the measurement information acquisition module is used for acquiring measurement information corresponding to each transmission branch in a plurality of transmission branches deployed in a wide area;

a target transmission branch selecting module, configured to select a target transmission branch from the multiple transmission branches based on the measurement information, where the number of the target transmission branches is within a first interval range;

a configuration message frame sending module, configured to send configuration message frames to the mobile station by using the target sending branches, respectively;

a configuration response message frame receiving module, configured to receive a configuration response message frame corresponding to the configuration message frame returned by the mobile station;

a data frame sending module, configured to send data frames to the mobile station by using the target sending branches respectively based on the configuration response message frame;

wherein, the configuration message frame sending module comprises the following sub-modules:

a delay information obtaining submodule, configured to obtain delay information indicated in measurement information corresponding to the target transmission branch;

and the delay sending submodule is used for delaying and sending the configuration message frame of the corresponding sending branch based on the time delay information, wherein the signal frequency of the configuration message frame sent by each target sending branch is the same.

27. A mobile station, comprising:

a measurement information obtaining module, configured to obtain measurement information corresponding to channels between a plurality of transmission branches and the mobile station when handshake frames sent by the transmission branches are received, where the transmission branches are wide-area deployed transmission branches;

a measurement information frame sending module, configured to organize the measurement information into a measurement information frame, and return the measurement information frame to an access point;

a configuration message frame receiving module, configured to receive a configuration message frame sent by a plurality of target sending branches, where the target sending branches are sending branches selected by an access point from the plurality of sending branches based on the measurement information frame and the number of the sending branches is within a first interval range;

a configuration response message frame sending module, configured to return a corresponding configuration response message frame to the access point based on the configuration message frame;

a data frame receiving module, configured to receive data frames sent by the multiple target sending branches;

the configuration message frame receiving module is configured to receive the configuration message frame that is sent in a delayed manner by the target sending branch based on the obtained delay information indicated in the corresponding measurement information.

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