CN103795666A - Method for sending downlink pilot frequency in special network communication system - Google Patents

Abstract

This application discloses a method for sending downlink pilots in a private network communication system, including: A. setting a specific OFDM symbol in each wireless frame in each subband as a pilot resource group; B. for any cell, set The cell identifier is modulo 4, and the subcarrier where the pilot of the cell is located is determined in the pilot resource group according to the modulo result. By applying the scheme of this application, the pilot frequency of this cell can be prevented from being interfered by the business of the neighboring cell or the pilot frequency of the neighboring cell.

Description

A method for sending downlink pilots in a private network communication system

technical field

The present application relates to the technical field of mobile communication, and in particular to a method for sending downlink pilots in a private network communication system.

Background technique

The private network communication system occupies discontinuous spectrum bandwidth, as shown in Figure 1. Each 25kHz is a subband. There are a maximum of 480 subbands. A radio frame length of each subband of the private network system is 25 ms, including 45 OFDM symbols. As shown in FIG. 2 , downlink resources occupy 13 OFDM symbols, random access resources include 4 OFDM symbols, and uplink resources include 27 OFDM symbols.

绝对子带索引n_PRB、OFDM符号l来确定，具体如下：The downlink pilot pattern in a subband of the private network communication system is shown in Figure 3, and the gray mark indicates the location of the pilot. Each OFDM symbol has a resource element (RE, Resource Element) as a pilot, and the position of the pilot (k, l, n _PRB ) is based on the cell identity

Absolute subband index n _PRB , OFDM symbol l to determine, as follows:

$\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; shift</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; mod</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sc</span>}}^{\mathrm{<span\; class="notranslate">\; RB</span>}}$

l=0,1,...,12

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; PRB</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0,1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; RB</span>}}^{\mathrm{<span\; class="notranslate">\; DL</span>}}$

in $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}{N}_{\mathrm{SC}}^{\mathrm{RB}},$ $N_{\mathrm{sc}}^{\mathrm{RB}}=10,$ $N_{\mathrm{ID}}^{\mathrm{cell}}=\mathrm{0,1},...,503.$

由系统的带宽决定。

Determined by the bandwidth of the system.

When there is co-channel interference in the private network communication system, the pilot is sent according to the downlink pilot pattern shown in Figure 3, and the services of neighboring cells interfere with the pilot of this cell. It affects the accuracy of channel estimation and channel measurement, and then affects the demodulation performance of the system. For this reason, the pilot frequency needs to be redesigned to improve its anti-interference ability.

Contents of the invention

This application provides a method for sending downlink pilots in a private network communication system, which can prevent the pilots of the local cell from being interfered by adjacent cell services or adjacent cell pilots.

An embodiment of the present application provides a method for sending downlink pilots in a private network communication system, including:

A. Setting specific OFDM symbols in each radio frame in each subband as a pilot resource group;

B. For any cell, take the modulus of the cell ID to 4, and determine the subcarrier where the pilot of the cell is located in the pilot resource group according to the modulus result.

Preferably, the number of OFDM symbols serving as pilot resource groups is 3, and the distance between adjacent OFDM symbols serving as pilot resource groups is equal.

Preferably, the pilot resource group is fixed to be 8 resource elements among the 3rd, 7th, and 11th OFDM symbols of each radio frame.

It can be seen from the above technical solutions that a dedicated pilot resource group is set for each subband, and the pilots of different cells are distinguished by frequency division in the dedicated pilot resource group, so that the pilots of this cell are not affected. The interference of adjacent cell services or adjacent cell pilots can achieve the purpose of resisting co-channel interference.

Description of drawings

Figure 1 is a schematic diagram of the frequency spectrum of a private network communication system;

FIG. 2 is a schematic diagram of a subband time slot resource structure;

FIG. 3 is a private network downlink pilot pattern in the prior art;

FIG. 4 is a schematic flowchart of a method for sending downlink pilots in a private network communication system provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a downlink pilot pattern of a private network communication system provided by an embodiment of the present application.

Detailed ways

In the present invention, in the private network communication system, a dedicated pilot resource group is set for each subband, and in the dedicated pilot resource group, the pilots of different cells are distinguished by frequency division, so as to achieve the same-frequency interference resistance Purpose.

In order to make the technical principles, features and technical effects of the technical solution of the present application clearer, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

A flow of a method for sending downlink pilots in a private network communication system provided in an embodiment of the present application is shown in Figure 4, including:

Step 401: Set specific OFDM symbols in each radio frame in each subband as a pilot resource group. Preferably, the number of OFDM symbols serving as pilot resource groups is 3, and the distance between adjacent OFDM symbols serving as pilot resource groups is equal. All or part of the resource elements in the OFDM symbols of the pilot resource group are used as pilots.

In the embodiment of the present application, the pilot resource group is fixed to be 8 resource elements among the 3rd, 7th, and 11th OFDM symbols of each radio frame.

对4取模，根据取模结果在导频资源组内确定该小区导频所在的子载波。导频资源组中不发送导频的资源位置不发送任何信号。Step 402: identify the cell

Take a modulus of 4, and determine the subcarrier where the pilot of the cell is located in the pilot resource group according to the modulus result. The resource positions that do not transmit pilots in the pilot resource group do not transmit any signal.

Preferably, the pilot position (k, l, n _PRB ) can be determined according to the following formula.

k＝V _shift +1, V _shift +5

l=2,6,10

n _PRB = 0,1,...,479

in $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}4,$ $N_{\mathrm{ID}}^{\mathrm{cell}}=\mathrm{0,1},...,503.$

in, is the cell identifier, and n _PRB is the absolute subband index.

Fig. 5 shows the downlink pilot pattern of the private network communication system provided by the embodiment of the present application, wherein the snowflake-shaped shadow indicates the position of the pilot resource group, and the grid-shaped shadow indicates the location of the pilot of one of the cells.

By applying the scheme of this application, the pilot frequency of the local cell can be prevented from being interfered by the business of the neighboring cell or the pilot frequency of the neighboring cell, so as to achieve the purpose of resisting co-channel interference.

The above descriptions are only preferred embodiments of the application, and are not intended to limit the scope of protection of the application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the technical solutions of the application are It should be included within the protection scope of this application.

Claims (3)

1. A method for sending downlink pilot frequency in a private network communication system is characterized by comprising the following steps:

A. setting specific OFDM symbols in each wireless frame in each sub-band as a pilot frequency resource group;

B. and for any cell, performing modulus operation on the cell identifier 4, and determining the subcarrier where the pilot frequency of the cell is located in the pilot frequency resource group according to the modulus operation result.

2. The method of claim 1, wherein the number of OFDM symbols as the set of pilot resources is 3, and wherein the spacing between adjacent OFDM symbols as the set of pilot resources is equal.

3. The method of claim 2, wherein the set of pilot resources is fixed to 8 resource elements in the middle of 3 rd, 7 th, and 11 th OFDM symbols of each radio frame.

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