WO2012075883A1

WO2012075883A1 - Sounding sequence allocation method and base station

Info

Publication number: WO2012075883A1
Application number: PCT/CN2011/082617
Authority: WO
Inventors: 刘敏
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-12-07
Filing date: 2011-11-22
Publication date: 2012-06-14
Also published as: CN102573069A; CN102573069B

Abstract

The present invention provides a sounding sequence allocation method and base station. The method comprises: a base station estimates the distance between a terminal and the base station according to a channel condition fed back by the terminal; the base station determines the terminal type according to the estimated distance, wherein the terminal type comprises at least a near point terminal and a far point terminal; and the base station allocates a sounding sequence for the terminal according to the terminal type. The present invention reduces interference in the uplink sounding area, satisfies base station-side modulation, and obtains downlink beam-forming gain, thus ensuring successful downlink beam-forming.

Description

The present invention relates to the field of communications, and in particular to a method and a base station for allocating a sounding sequence. BACKGROUND OF THE INVENTION Orthogonal Frequency Division Multiple Access (OFDMA) is a special multi-carrier transmission technology that distributes high-speed data streams into several sub-channels through serial, variable, and change. Transmission, which greatly improves spectrum efficiency and effectively resists multipath interference and narrowband interference, has become one of the core technologies of the next generation mobile communication system. WIMAX, the global microwave access compatible, WIMAX802.16e standard that uses 0FDMA technology as its physical core technology and takes into account mobility and broadband characteristics, has become a strong competitor of the next generation mobile communication standard. Beam-Forming (BF) is a multi-antenna transmission technology for antenna arrays with small spacing. The main principle is to generate strong directional radiation directions by using the strong correlation of spatial channels and the interference principle of waves. The figure makes the main lobe of the radiation pattern adaptively point to the direction of the user's incoming wave, thereby improving the signal-to-noise ratio and increasing the system capacity or coverage. Although the pattern of the array antenna is omnidirectional, the output of the array is weighted and summed, so that the direction gains received by the array are concentrated in one direction, which is equivalent to forming a beam. This process of weighting and combining signals from different array elements is beamforming. A schematic diagram of a beam generated by a uniform linear line element as shown in Figure 1. The mathematical model can be described as follows: Assuming that the input data is ..., the system with a weight of ·, the output is: yit) = ws, +

+... + w „ = w ^ff s(t), where T is transpose, w = · · w„ ] ^Γ , s(t) = [ ... ] ^Γ . The reason why the antenna is called "smart antenna" is that the weight vector of the antenna array ^, ... can control the direction of the antenna array, as shown in the beamforming baseband processing diagram shown in Figure 2, the data in the data source is channel coded, Beamforming is performed after modulation, and then processed by OFDM modulation to form beams of different directions. The weighting factor can be optimally adjusted according to the adaptive algorithm to match the current transmission environment. The beamforming is directly based on the channel parameters. For the uplink (UL, Up Link), since reliable channel real-time or periodic estimation can be obtained, the space-time parameters of the channel can be used for beamforming to improve Uplink performance. For the downlink (DL, Down Link), reliable real-time estimation of the channel is difficult to achieve on the downlink due to conditional constraints. For the TDD mode system, under the condition that the uplink and downlink channel interval slots are small, the channel can be approximated as not changing, so that the estimated value of the channel empty time domain parameter obtained by the uplink data can be used on the downlink, and even Data that is shaped directly using the uplink beam. Since the uplink and downlink share the same frequency band resource in the TDD mode, the downlink channel estimation can be performed by the uplink sounding sequence.

The Sounding sequence is a channel detection mechanism. According to the 802.16e protocol, a BS (Base Station) requires certain MSs (Mobile Subscribers) to transmit a sounding waveform on a specific frequency band of the uplink channel. The BS receives this. After the waveform, the channel impulse response of the downlink channel of the estimated BS-to-MS is judged based on the waveform. The BS measures the uplink channel response by sounding and converts the result into the response of the downlink channel to be estimated. The hardware at both ends of the transceiver needs to be properly collated. The Sounding sequence described in the protocol can be divided into two types, type A and P type B. The difference between the two is in the way the subcarriers of the sounding zone are allocated. Type A divides the subcarriers in the Sounding Zone into bands that do not overlap each other, and each band contains 18 consecutive subcarriers. Then specify the MS to send a sounding waveform on the specified band. Type B is transmitted according to the common subcarrier allocation method, in which the subchannel is used as an allocation unit, and the designated MS is transmitted on the determined subchannels and symbols. Whether the base station and the terminal support Type A Sounding or Type B Sounding, and obtain the intersection result of the CSIT capability through the SBC (System Broadcast Channel) capability negotiation in the terminal access process.

The TYPE A type is divided into Cyclic (cyclic shift) and Decimation (carrier numerical extraction). For CSIT capability A, if the Separability type in the UL Sounding Command IE (separation type) ) is 0, indicating that the Sounding sequence is Cyclic, and the terminal distinguishes between the frequency bands allocated in the Sounding area by cyclic shift. The separability type is 1, indicating the Sounding sequence Decimation mode, indicating that the terminal sends the Sounding sequence to distinguish by the offset bit. Beamforming BF technology is a multi-antenna technology for downlink beamforming by uplink channel estimation. Therefore, it is necessary to rely on uplink resources and channel conditions for beamforming. The uplink channel estimation is called weight estimation. The Sounding sequence is a key uplink weight estimation method. The detection and demodulation of the Sounding sequence directly affects the gain of the downlink shaping, and the Sounding sequence is the information without encoding. The information is disturbed and cannot be recovered, which in turn affects the downstream beamforming process. SUMMARY OF THE INVENTION The present invention provides a method and a base station for allocating a sounding sequence to reduce interference problems in the uplink sounding region. According to an aspect of the present invention, a method for allocating a sounding sequence is provided, the method comprising: estimating, by a base station, a distance between a terminal and a base station according to a channel condition fed back by the terminal; the base station determining a type of the terminal according to the estimated distance, the type of the terminal At least: a near-point terminal and a far-end terminal; the base station allocates a sounding sequence to the terminal according to the type of the terminal. Preferably, the determining, by the base station, the distance between the terminal and the base station according to the channel condition fed back by the terminal comprises: the terminal initially accessing the network, and the base station determining the distance between the terminal and the base station according to the received signal strength indication RSSI fed back by the terminal. Preferably, the determining, by the base station, the type of the terminal according to the estimated distance comprises: if the estimated distance is greater than the first set value, the base station determines that the terminal is a near-point terminal; if the estimated distance is less than or equal to the first setting The fixed value, the base station determines that the terminal is a far-end terminal. Preferably, the type of the terminal further includes: a midpoint terminal; determining, by the base station, the type of the terminal according to the estimated distance: if the estimated distance is greater than a first set value, the base station determines that the terminal is a near-point terminal; If the estimated distance is less than the second set value, the base station determines that the terminal is a far-end terminal; if the estimated distance is less than or equal to the first set value, and the distance is greater than or equal to the second set value, The base station determines that the terminal is a midpoint terminal. Preferably, the foregoing base station allocates a sounding sequence to the terminal according to the type of the terminal, and the base station searches for a configuration value corresponding to the sounding sequence according to the determined type of the terminal; wherein the configuration value is set by the base station according to the type of the terminal in advance. And including a decimation interval value in the carrier number extraction manner and a symbol used by the detection sequence; the base station allocates the extraction interval value and the detection sequence corresponding to the symbol used by the detection sequence to the terminal. Preferably, after the terminal accesses the network, after the base station allocates the sounding sequence to the terminal according to the type of the terminal, the method further includes: determining, by the base station, whether the type of the terminal changes in each decision period, and if yes, according to the changed The type of the terminal reassigns the probe sequence to the terminal. Preferably, the determining, by the base station, whether the type of the terminal changes in each determination period comprises: after the current decision period is reached, the base station calculates an average value Ri of the RSSI of the terminal that is counted in the current determination period, where the value is greater than 1. Integer Calculating a mean square error of Ri-1 and Ri, where Ri-1 is an average value of the RSSI of the terminal measured in the last decision period of the current decision period; if the mean square error is greater than a set deviation threshold, The base station determines that the type of the terminal changes; if the mean square error is not greater than the set deviation threshold, the base station determines that the type of the terminal does not change. Preferably, the foregoing base station allocates a sounding sequence to the terminal according to the type of the terminal, and the base station sends a sounding sequence indication message to the terminal, where the sounding sequence indication message carries the allocated sounding sequence indication information. According to another aspect of the present invention, a base station is provided, including: a distance obtaining module, configured to estimate a distance between a terminal and a base station according to a channel condition fed back by the terminal; and a type determining module, determining a type of the terminal according to the distance estimated by the distance acquiring module The terminal type includes at least: a near-point terminal and a far-end terminal; and a sounding sequence allocation module configured to allocate a sounding sequence to the terminal according to the type of the terminal determined by the type determining module. Preferably, the type determining module includes: a first determining unit, configured to: if the estimated distance is greater than the first set value, determining that the terminal is a near-point terminal; if the estimated distance is less than or equal to the first set value , determine that the terminal is a far-end terminal. Preferably, the type of the terminal determined by the type determining module further includes: a midpoint terminal; the type determining module includes: a second determining unit, configured to determine that the terminal is near if the estimated distance is greater than the first set value Point terminal; if the estimated distance is less than the second set value, determining that the terminal is a far end terminal; if the estimated distance is less than or equal to the first set value, and the distance is greater than or equal to the second set value , determine that the terminal is a midpoint terminal. According to the invention, the detection sequence allocation is performed according to the distance between the terminal and the base station, the interference in the uplink sounding area is reduced, and the demodulation of the base station side is satisfied, and the gain of the downlink shaping is obtained, thereby ensuring the smooth progress of the downlink beamforming. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawing: 1 is a schematic diagram of generating a beam by a uniform linear line element according to the related art; FIG. 2 is a schematic diagram of beamforming baseband processing according to the related art; FIG. 3 is a flowchart of a method for allocating a sounding sequence according to Embodiment 1 of the present invention; 4 is a flowchart of a method for allocating a sounding sequence of a terminal during initial access according to Embodiment 2 of the present invention; FIG. 5 is a flowchart of a method for allocating a sounding sequence after terminal access according to Embodiment 2 of the present invention; A block diagram of a base station according to Embodiment 3 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The embodiment of the present invention considers that the existing terminal does not support the separate power control of the Sounding area,

The Sounding sequence allocation reduces the interference in the Sounding area of the entire network, and at the same time satisfies the demodulation on the base station side to obtain the downlink shaping gain. Embodiment 1 FIG. 3 is a flowchart of a method for allocating a sounding sequence according to an embodiment of the present invention. The method includes the following steps: Step S302: The base station estimates a distance between a terminal and a base station according to a channel condition fed back by the terminal; For example, the terminal initially accesses the network, and the base station measures the distance between the terminal and the base station according to the received signal strength indication (RSSI). The signal strength of the RSSI can be used to determine the distance between the signal point and the receiving point, and then the positioning calculation can be performed according to the corresponding data. The RSSI fed back by the terminal in this embodiment can be represented by DLRSSI, that is, the downlink received signal strength. Step S304, the base station determines the type of the terminal according to the estimated distance. In this embodiment, the type of the terminal at least includes: a near-end terminal and a far-end terminal; In a specific implementation, a fixed value may be set in the base station as the first set value. If the estimated distance is greater than the first set value, the base station determines that the terminal is a near-point terminal; if the estimated distance is less than or equal to the first set The fixed value, the base station determines that the terminal is a far-end terminal. Preferably, in order to achieve better noise reduction, the type of the terminal may be classified into three types according to the distance between the terminal and the base station, that is, the near-point terminal, the far-end terminal, and the mid-point terminal; and at the same time, setting on the base station The two values are respectively a first set value and a second set value. Based on this, the determining, by the base station, the type of the terminal according to the estimated distance comprises: if the estimated distance is greater than the first set value, the base station determines that the terminal is a near point a terminal; if the estimated distance is less than the second set value, the base station determines that the terminal is a far-end terminal; if the estimated distance is less than or equal to the first set value, and the distance is greater than or equal to the second set value, the base station determines that the terminal is in the middle Point terminal. Step S306, the base station allocates a sounding sequence to the terminal according to the type of the terminal. When the base station of the embodiment performs the sounding sequence allocation, the base station searches for the configuration value corresponding to the sounding sequence according to the determined type of the terminal. The configuration value is set by the base station according to the type of the terminal in advance, including the number of carriers. The interval value and the symbol used by the sounding sequence are extracted; then, the base station allocates the above-mentioned extraction interval value and the sounding sequence corresponding to the symbol used by the sounding sequence to the terminal. Considering that the terminal has mobility, the distance between the terminal and the base station also changes. In this embodiment, when the sounding sequence is allocated, a decision period is set on the base station, and the type of the terminal is determined without a period of time. Update the allocation of the probe sequence. Based on this, after the terminal accesses the network, the base station allocates a sounding sequence to the terminal according to the type of the terminal, and the method further includes: determining, by the base station, whether the type of the terminal changes in each decision period, and if yes, according to the changed terminal. The type is the terminal reassignment probe sequence. The determining, by the base station, whether the type of the terminal changes in each decision period includes: after the current decision period is reached, the base station calculates an average value of the RSSI of the terminal that is counted in the current determination period, where i is an integer greater than 1; ^- and! The mean square error of ^, where is the average value of the RSSI of the terminal measured in the last decision period of the current decision period; if the mean square error is greater than the set deviation threshold, the base station determines that the type of the terminal changes; if the mean square error Not greater than the set deviation threshold, the base station determines that the type of the terminal has not changed. The base station allocates a sounding sequence to the terminal according to the type of the terminal, and the base station sends a sounding sequence indication message to the terminal, where the sounding sequence indication message carries the allocated sounding sequence indication information. After receiving the sounding sequence indication message, the terminal sends a sounding sequence according to the sounding sequence indication information. The Sounding sequence allocation method in this embodiment is applicable to the TYPE A type and the TYPE B type, and is preferably applied to the TYPE A type. The TYPE A type is divided into Cyclic and P Decimation. Different sequence types and different configuration terminals have different number of subcarriers for transmitting the Sounding sequence. Considering that the Cyclic method requires the terminal to transmit high power, the above method can be used in the Decimation mode. .

The sequence offset D value in the Decimation mode indicates the number of users transmitting a Sounding sequence on a symbol. The larger the D value is, the more Sounding users can be allocated on one symbol, the fewer the number of Sounding sequence carriers occupied by each user; and the smaller the D value, the fewer users can be allocated on one symbol, and the number of users per user. The number of sounding sequence carriers is higher. The transmit power of the terminal is limited. The CINR (Signal to Noise Ratio) of the Sounding area reaches a certain threshold to satisfy the demodulation on the base station side, and achieves better downlink beam gain. Therefore, in this embodiment, the allocation of the Sounding sequence of the control terminal is adopted, so that the limited transmission power of the terminal at the far point can also satisfy the transmission of the Sounding sequence, and the near-point user can also achieve the best shaping gain. In this embodiment, the detection sequence is allocated according to the distance between the terminal and the base station, which reduces the interference of the Sounding area in the whole network, and can simultaneously satisfy the demodulation of the base station side, obtain the gain of the downlink shaping, and ensure the smooth progress of the downlink beamforming. . Embodiment 2 This embodiment provides a method for allocating a sounding sequence. In this method, a Sounding sequence used between a base station and a terminal is a Decimation mode in a TYPE A type. In this embodiment, the distance between the terminal and the base station is estimated by the channel condition of the terminal (for example, RSSI), and the terminal is divided into far, medium, and near three types of terminals. The base station divides the Sounding Zone before the allocation of the sounding sequence: the base station first initializes the information of the uplink Sounding Zone, assigns the Sounding Zone to three symbols, and the three sounding sequence types of the Sounding Zone are fixed, and are respectively set to different D values. The D values of the three symbols are reserved for the users of the far point area, the midpoint area, and the near point area, respectively. Of course, when no user allocates a Sounding sequence, the uplink does not need to be divided into Sounding Zones to save uplink bandwidth resources. Due to the limited transmit power of the terminal, the far-end terminal has large path loss, and the terminal has high transmit power. In order to satisfy the base station side demodulation, the limited power of the terminal needs to be distributed on fewer carriers to avoid the terminal transmit power saturation, so it is far away. The Sounding sequence assigned by the terminal is a Type A type of Decimation mode, and the D value is greater than M; For the midpoint terminal, the terminal is farther away from the base station, and the distance to the neighboring area is far, the interference is small, the number of Sounding carriers that can be allocated is more, and the power of the terminal can also satisfy the transmission of the Sounding sequence, and the D of the midpoint terminal can be The value takes the value [M, N]. For the near-point terminal, the path loss is small, the terminal transmit power does not have saturation problem, and the neighboring area interference is small. In order to achieve the maximum beamforming gain, the number of Sounding carriers can be assigned more D values than N. The base station configures different symbols for the three types of terminals, and the corresponding relationship is as shown in Table 1. Table 1

Based on the above correspondence, FIG. 4 is a flowchart of a method for allocating a sounding sequence according to the present embodiment. The method includes the following steps: Step S402: The terminal initially accesses the network, and the terminal reports DLRSSI; Step S404, the base station calculates a statistical DLRSSI average. Step S406, the base station determines whether the DLRSSI is > the first set value F, if yes, step S408 is performed; if no, step S410 is performed; step S408, the base station determines that the terminal is a near-point terminal; step S410, the base station determines whether the DLRSSI is <the second set value L, if yes, go to step S412; if no, go to step S414; step S412, the base station determines that the terminal is a far-end terminal; step S414, the base station determines that the terminal is a midpoint terminal; step S416, the base station Allocating a sounding sequence to the terminal according to the type of the terminal, Wherein, F and L are thresholds of two DLRSSIs preset by the base station, and the distance interval is divided into three points in the far distance. Among them, the far-end terminal: DLRSSI <F; midpoint terminal: DLRSSI between [F, L]; near-point terminal: DLRSSI > L. Referring to FIG. 5, after the terminal accesses the base station, the specific steps of allocating the Sounding sequence are as follows: Step S502: The base station side receives the DLRSSI reported by the terminal, and the base station obtains the downlink signal strength from the DLRSSI; Step S504, the base station side arrives to determine the decision. The base station calculates the average value of the DLRSSI of the period statistics. Step S506: The base station side determines the type of the terminal according to the average value of the DLRSSI. The distance between the terminal and the base station is estimated according to the interval in which the DLRSSI falls. If the DLRSSI < L, the terminal is determined to be The far-end terminal, if F < DLRSSI < L, determines that the terminal is a mid-point terminal, and if DLRSSI > F, it determines that the terminal is a near-point terminal. Step S508, determining whether the type of the terminal changes, if yes, executing step S510, and if no, executing step S512. To determine whether the type of the terminal changes, you can use: Calculate the mean variance of the last saved RSSI1 sample and the latest statistical RSSI2 sample. If the variance exceeds the set deviation threshold X, the type of the terminal changes; otherwise, the terminal is described. The type has not changed. Step S510, the base station side instructs the terminal to stop the original Sounding sequence transmission, and reallocates the Sounding sequence lj for the terminal; Step S512, the process ends. In this embodiment, the types of the terminals are classified into three types, and the sounding sequence is allocated to the terminal according to the sounding sequence configuration information corresponding to the three types, so that the limited transmission power of the terminal can satisfy the transmission of the Sounding sequence, and meet the demodulation requirements of the base station side. Reduces interference in the Sounding area of the entire network. Embodiment 3 FIG. 6 is a structural block diagram of a base station according to an embodiment of the present invention. The base station includes: a distance acquiring module 62, configured to estimate a distance between a terminal and a base station according to channel conditions fed back by the terminal; The terminal initially accesses the network, and the distance obtaining module 62 determines the distance between the terminal and the base station according to the received signal strength indication RSSI fed back by the terminal; the type determining module 64 is connected to the distance obtaining module 62, and the distance estimated by the distance obtaining module 62. Determining the type of the terminal, the type of the terminal at least includes: a near-point terminal and a far-end terminal; the probe sequence assignment module 66 is connected to the type determination module 64, and is configured to allocate a probe sequence to the terminal according to the type of the terminal determined by the type determination module 64. The type determining module 64 includes: a first determining unit, configured to: if the estimated distance is greater than the first set value, determine that the terminal is a near-point terminal; if the estimated distance is less than or equal to the first set value, determine that the terminal is a far-end terminal . Alternatively, if the type of the terminal further includes the midpoint terminal, the type of the terminal determined by the type determining module 64 further includes: a midpoint terminal; based on this, the type determining module 64 includes: a second determining unit, configured to: if the estimated distance is greater than a first set value, determining that the terminal is a near-point terminal; if the estimated distance is less than the second set value, determining that the terminal is a far-end terminal; if the estimated distance is less than or equal to the first set value, and the distance is greater than or equal to the first The second set value determines that the terminal is a midpoint terminal. The probe sequence allocation module 66 includes: a search unit configured to search for a configuration value corresponding to the sounding sequence according to the determined type of the terminal; wherein, the configuration value is set by the base station according to the type of the terminal, including the extraction in the carrier number extraction mode. The interval value (ie, the above D value) and the symbol used by the sounding sequence; the allocation unit is configured to allocate the above-mentioned extraction interval value and the sounding sequence corresponding to the symbol used by the sounding sequence to the terminal. The base station of this embodiment determines whether the type of the terminal changes in each decision period, and if so, re-allocates the sounding sequence for the terminal according to the type of the changed terminal. For example, after the current decision period is reached, the base station calculates the average value of the RSSI of the terminal that is counted in the current determination period, where i is an integer greater than one; ^ and! The mean square error of ^, where is the average value of the RSSI of the terminal measured in the last decision period of the current decision period; if the mean square error is greater than the set deviation threshold, the base station determines that the type of the terminal changes; if the mean square error is not Above the set deviation threshold, the base station determines that the type of the terminal has not changed. The base station of this embodiment further includes: a sending module, configured to send a sounding sequence indication message to the terminal, where the sounding sequence indication message carries the allocated sounding sequence indication information. In this embodiment, the detection sequence is allocated according to the distance between the terminal and the base station, which reduces the interference of the Sounding area in the whole network, and can simultaneously satisfy the demodulation of the base station side, obtain the gain of the downlink shaping, and ensure the smooth progress of the downlink beamforming. . From the above description, it can be seen that the BF beamforming technology described in the present invention is a multi-antenna technology for performing downlink beamforming by uplink channel estimation, and therefore it is necessary to rely on uplink resources and channel conditions for beamforming. The invention reduces the interference of the Sounding area in the whole network by the Sounding sequence allocation, and at the same time satisfies the demodulation of the base station side and obtains the downlink shaping gain. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing base station, which can be concentrated on a single computing base station or distributed over a network composed of multiple computing base stations. Alternatively, they may be implemented by calculating program code executable by the base station, so that they may be stored in the storage base station by the computing base station, and in some cases, may be different from the order here. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for allocating a sounding sequence, comprising:

The base station estimates the distance between the terminal and the base station according to the channel condition that is fed back by the terminal; the base station determines the type of the terminal according to the estimated distance, and the type of the terminal includes at least: a near-end terminal and a far-end terminal;

The base station allocates a sounding sequence to the terminal according to the type of the terminal.

The method according to claim 1, wherein the base station estimates the distance between the terminal and the base station according to channel conditions fed back by the terminal, including:

The terminal initially accesses the network, and the base station determines the distance between the terminal and the base station according to the received signal strength indication RSSI fed back by the terminal.

The method according to claim 1, wherein the determining, by the base station, the type of the terminal according to the estimated distance comprises:

If the estimated distance is greater than the first set value, the base station determines that the terminal is a near-point terminal; if the estimated distance is less than or equal to the first set value, the base station determines that the terminal is Far point terminal.

The method according to claim 1, wherein the type of the terminal further comprises: a midpoint terminal;

Determining, by the base station, the type of the terminal according to the estimated distance, includes:

If the estimated distance is greater than the first set value, the base station determines that the terminal is a near-point terminal; if the estimated distance is less than a second set value, the base station determines that the terminal is a far-end terminal; If the estimated distance is less than or equal to the first set value, and the distance is greater than or equal to the second set value, the base station determines that the terminal is a midpoint terminal.

The method according to claim 1, wherein the base station assigns a sounding sequence to the terminal according to the type of the terminal, including:

And the determining, by the base station, the configuration value corresponding to the detection sequence according to the determined type of the terminal, where the configuration value is set by the base station according to the type of the terminal, and includes the extraction interval value and the detection sequence in the carrier number extraction mode. Symbol used;

The base station allocates, to the terminal, the extraction interval value and a detection sequence corresponding to a symbol used by the sounding sequence.

The method according to claim 1, wherein, after the terminal accesses the network, after the base station allocates a sounding sequence to the terminal according to the type of the terminal, the method further includes:

The base station determines whether the type of the terminal changes in each decision period, and if so, re-allocates the sounding sequence for the terminal according to the changed type of the terminal.

The method according to claim 6, wherein the determining, by the base station, whether the type of the terminal changes in each decision period comprises:

After the current decision period is reached, the base station calculates an average value of the RSSI of the terminal that is counted in the current determination period, where i is an integer greater than one;

Calculating a mean square error of and, wherein an average value of the RSSI of the terminal is calculated for the last decision period of the current decision period;

If the mean square error is greater than a set deviation threshold, the base station determines that the type of the terminal changes;

If the mean square error is not greater than the set deviation threshold, the base station determines that the type of the terminal has not changed.

The method according to any one of claims 1 to 7, wherein the base station assigning a sounding sequence to the terminal according to the type of the terminal includes:

The base station sends a sounding sequence indication message to the terminal, where the sounding sequence indication message carries the allocated sounding sequence indication information.

9. A base station comprising:

a distance obtaining module, configured to estimate a distance between the terminal and the base station according to a channel condition fed back by the terminal;

a type determining module, determining a type of the terminal according to the distance estimated by the distance obtaining module, where the type of the terminal at least includes: a near-end terminal and a far-end terminal;

The sounding sequence allocation module is configured to allocate a sounding sequence to the terminal according to the type of the terminal determined by the type determining module.

The base station according to claim 9, wherein the type determining module comprises:

a first determining unit, configured to determine that the terminal is a near-point terminal if the estimated distance is greater than a first set value; and determine the terminal if the estimated distance is less than or equal to the first set value For the terminal.

The base station according to claim 9, wherein the type of the terminal determined by the type determining module further comprises: a midpoint terminal;

The type determination module includes:

a second determining unit, configured to: if the estimated distance is greater than the first set value, determining that the terminal is a near-point terminal; if the estimated distance is less than a second set value, determining that the terminal is a far-end terminal And if the estimated distance is less than or equal to the first set value, and the distance is greater than or equal to the second set value, determining that the terminal is a midpoint terminal.