CN100401660C - A detection method for user terminal random access - Google Patents

Abstract

The present invention relates to a detection method for the random access of a user terminal, which is used for a wireless communication system in a time division duplex mode. The present invention comprises the steps: upstream pilot frequency codes sent by a user terminal and N upstream pilot frequency codes of the current cell are separately shifted and correlated to obtain N correlation power sequences where N is a positive integer; the maximum power value in each of the correlation power sequences is calculated to form a maximum power sequence with the length of N, and the maximum value in the maximum power sequence is calculated; a threshold value is selected, is compared with the maximum power value or the maximum value in the maximum power sequence, and is judged; when a condition is satisfied, the corresponding upstream pilot frequency codes are judged to be upstream pilot frequency codes selected by a user terminal, and the sequence of the pilot frequency codes is determined. The detection method of the present invention can realize the detection of the random access of one or a plurality of user terminals quickly and accurately, can simplify the existing detection algorithm for random access and can be used alone. The detection method of the present invention can also be combined with the existing judgment condition for the detection of pilot frequency code conflict to realize the detection process of multiuser conflict.

Description

A detection method for user terminal random access

technical field

The present invention relates to wireless communication technology, in particular to a method for detecting random access of a user terminal (UE) in a time division duplex mode (TDD) wireless communication system.

Background technique

In the TD-SCDMA system, the synchronization detection of user terminal random access refers to the process of establishing uplink synchronization between one or more user terminals and the base station.

After the user terminal is turned on, it must first establish downlink synchronization with the cell (cell). Uplink synchronization can only be established under the condition of downlink synchronization.

Conversely, the establishment of uplink synchronization is completed during the random access process of the user terminal. The establishment of uplink synchronization involves uplink pilot channel (UpPCH) and physical random access channel (PRACH). Although the user terminal can receive the downlink signal from the base station (Node B), the distance to the Node B is still uncertain, which leads to asynchronous uplink transmission between different user terminals, in order to reduce the resulting business time slot The first transmission in the uplink direction is carried out in the special time slot of Uplink Pilot Time Slot (UpPTS).

Referring to Figure 1, the establishment of uplink synchronization generally includes the following steps: step 1, the user terminal sends a specific uplink pilot code signal (SYNC-UL sequence) through the uplink in the uplink pilot time slot; step 2, the Node B searches for After the SYNC-UL sequence is detected in the window (including the guard time slot GP and the uplink pilot time slot UpPTS), the time is estimated, and the adjustment information is sent to the user terminal. Step 2 passes through the fast physical access channel (FPACH) after step 1 WT (1-4, the maximum value is 4) subframes; step 3, the user terminal adjusts the transmission time of the next transmission according to the adjustment information of the Node B, and establishes uplink synchronization after sending the PRACH. The uplink synchronization process can also be used to re-establish uplink synchronization when uplink synchronization is lost.

In the above steps, the synchronization detection identifies the SYNC_UL sequence by analyzing the antenna data obtained in the guard time slot and the uplink pilot time slot. If a valid SYNC_UL sequence is detected, the calculation of the beamforming weight coefficient and the synchronization offset of the FPACH are completed. shift (SS) and power control (PC) command generation and some measurement tasks.

Generally, the function of synchronization detection can be divided into two parts: SYNC_UL signature identification, including antenna data acquisition, matched filtering, signature identification, and FPACH arrangement; and parameter measurement, including SYNC_UL received power measurement, beamforming weighting coefficient measurement, FPACH power Control (PC) command generation, RACH interference power measurement, and FPACH synchronization offset (SS) command generation.

Among the above functions, signature recognition can be considered as the core part of the entire synchronous detection technology. The algorithm used is directly related to the performance of random access, and the performance of the corresponding user access detection algorithm directly affects whether the user can correctly Access to the wireless network, while wrong user access (including wrong access when there is no UE and wrong access when multi-user uplink pilots collide) directly leads to system performance degradation and waste of system resources.

Existing synchronous detection methods, especially signature identification methods are as follows:

Generally, the uplink pilot code signal sent by each user terminal usually has good autocorrelation, and the base station can use the correlation of the pilot code to adopt various mature correlation operations such as direct sequence convolution (linear correlation) or matched filtering. The method combines certain detection and judgment conditions to detect the corresponding pilot code information sent by the user, so as to detect the random access of the user terminal.

The antenna data acquisition and matched filtering process are as follows:

Antenna data acquisition is used to determine the data segment e where SYNC_UL is located. The detection window includes GP and UpPTS, that is, from the end position of the downlink pilot channel (DwPTS) to the end position of time slot 1 (TS1). The length of the data segment is 256chips (that is, including the GP time slot of 96 chips and the UpPTS time slot of 160 chips), and the baseband received signal after channel and additive noise can be expressed as:

$e\left(l\right)=h*{\mathrm{the\; s}}_{\mathrm{UL}}+\mathrm{no}=\underset{i=1}{\overset{128}{\mathrm{\&Sigma;}}}h\left(i\right)\&Center\; Dot;{\mathrm{the\; s}}_{\mathrm{UL}}(l-i)+\mathrm{no}\left(l\right),$ 1<l<256(1)

Among them, h represents the actual channel impulse response, S _UL represents a certain uplink pilot code, n represents additive noise and interference, and the symbol * represents the convolution process.

The tap-related power sequence after matched filtering of the same uplink pilot code can be expressed as:

$\mathrm{the\; y}\left(k\right)=\underset{j=1}{\overset{128}{\mathrm{\&Sigma;}}}{\mathrm{the\; s}}_{\mathrm{UL}}\left(j\right)e(j+k),$ -128<k<256(2)

Substituting Equation (1) into Equation (2) gives:

$\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \{</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 128</span>}<span\; class="notranslate">\; \&times;</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>{<span\; class="notranslate">\; |</span>}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>$

(3)

Let the channel impulse response tap in the above formula be $h\left(k\right)=128\&times;\underset{i=1}{\overset{128}{\mathrm{\&Sigma;}}}[h\left(i\right)\&CenterDot;\mathrm{\&delta;}(k-i)]$ , and let the noise and interference taps

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>{<span\; class="notranslate">\; |</span>}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 128</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; UL</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</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">\; 4</span>}<span\; class="notranslate">\; )</span>$

Then equation (3) can be simplified as:

y(k)=h(k)+h _n (k) (5)

Note that if the uplink pilot code signal satisfies good autocorrelation characteristics, that is, ACF(τ)=0 when τ≠0, then the second term in equation (3) can be approximately 0.

Signature identification process: Signature identification is to detect and judge the tap-related power sequence y(k) in equation (3), and only when certain detection conditions are met can it be judged that there is SYNC_UL access.

Therefore, the detection condition is particularly important for the correct judgment of SYNC_UL. The existing random access detection algorithm usually needs three kinds of judgment conditions for judgment, and the efficiency needs to be improved.

Contents of the invention

The technical problem to be solved by the present invention is to provide a detection method for random access of user terminals, which can quickly and accurately realize the detection of random access of one or more user terminals, and can simplify the existing random access detection algorithm and implement Easier and more convenient.

In order to solve the above problems, the method for detecting random access of user terminals of the present invention includes the following steps:

Step S1, performing shift correlation on the received uplink pilot code signal sent by the random access user terminal and the N uplink pilot codes of the cell to which the user terminal belongs to obtain N correlation power sequences, where N is a positive integer;

Step S2, calculating the maximum power value in each related power sequence, forming a maximum power sequence with a length of N, and calculating the maximum value in the maximum power sequence;

Step S3, select a threshold value, compare and judge with the maximum power value, or the maximum value in the maximum power sequence, and when the conditions are met, determine that the corresponding uplink pilot code sequence is an uplink pilot code sequence selected by a user terminal code sequence and determine the pilot code sequence.

Described step S3 specifically comprises:

Step S3.11, setting the first threshold value and the second threshold value;

Step S3.12, find the maximum power value greater than the first threshold value in the maximum power sequence, form a sequence P1 with a length of L, and find the uplink pilot code sequence corresponding to the sequence P1, and continue to execute if the sequence P1 exists Step S3.13, otherwise it is determined that no user access request is detected;

Step S3.13, subtracting the maximum value in the maximum power sequence from the value in the sequence P1, finding all values in the difference that are smaller than the second threshold value, forming a sequence P2 with a length of M, and calculating the sequence P2 For the corresponding uplink pilot code sequence, if M is greater than 0, that is, the sequence P2 exists, then it is determined that the uplink pilot code sequence corresponding to the sequence P2 is an uplink pilot code sequence selected by a user terminal, otherwise it is determined that no user access request is detected; or

Step S3.21, setting the first threshold value and the second threshold value;

Step S3.22, selecting a relevant power sequence corresponding to an uplink pilot code sequence;

Step S3.23, judging whether the maximum power value of the selected relevant power sequence is greater than the first threshold value, if it is true, continue to execute step S3.24, otherwise it is judged that no user has selected the uplink pilot code sequence;

Step S3.24, calculating the difference between the maximum value in the maximum power sequence and the maximum power value in step S3.23, judging whether the obtained difference is smaller than the second threshold value, and if so, judging the uplink pilot The code sequence is an uplink pilot code sequence selected by a user terminal, that is, the pilot code sequence sent by the user is determined, otherwise it is determined that no user has selected the uplink pilot code sequence.

If the judgment in the above step S3.23 is not established, or if the judgment in S3.24 is established or not, return to step S3.22 until all relevant power sequences are selected.

The above step S3 may also include:

Step S3.31, setting the first threshold value;

Step S3.32, judging whether the maximum value in the maximum power sequence is greater than the first threshold value, if it is true, then judging that the pilot code sequence corresponding to the maximum value is the pilot code sequence sent by a user terminal, otherwise judging If no uplink pilot code is received, that is, no user initiates a random access request;

After the above step S3, a step is further performed: adaptively updating the first and/or second threshold value according to the detection result (optional).

The number N of the above-mentioned uplink pilot code sequences is specifically 8.

The detection method of the present invention can realize single-user detection or multi-user detection by adjusting the threshold value, and can also combine the existing detection conflict judgment conditions to perform multi-user access conflict detection process, which reduces the number of judgments compared with the existing detection algorithm Conditions, the implementation steps are also significantly reduced, and it is easier to implement than existing detection algorithms.

Description of drawings

FIG. 1 is a schematic diagram of a random access process of a user terminal;

FIG. 2 is a flowchart of a random access process of a user terminal in the present invention;

FIG. 3 is a flowchart of a random access detection process according to the first embodiment of the present invention;

FIG. 4 is a flowchart of a random access detection process according to the second embodiment of the present invention;

FIG. 5 is a flowchart of a random access detection process according to the third embodiment of the present invention.

Detailed ways

Specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

According to the detection method of the random access of the user terminal of the present invention, before the random access process, the user terminal needs to prepare for random access, and receives the following parameter information from the upper layer (RRC layer):

a. 8 uplink pilot codes of the cell where the user terminal is located;

b. Uplink pilot code (signature) maximum retransmission times M;

c. User terminal transmit power adjustment step size ΔP;

d. The maximum number of waiting subframes WT for the user terminal to wait for the network to confirm a transmission signature. The value of WT is 1 to 4, and the default is 4 subframes.

After that, as shown in Figure 2, the user terminal performs random access, which specifically includes the following steps:

Step 11, set the signature retransmission counter M, the power adjustment step size ΔP and the number of WT subframes;

Step 12, determine initial transmit power P and transmit time;

Step 13, randomly select an uplink pilot code from the given 8 uplink pilot codes, and transmit with the initial transmission power P and transmission time determined in step 12;

Step 14, listen to the relevant FPACH after transmitting the uplink pilot code (signature), obtain network confirmation from the subsequent WT subframe, and the UE will read the FPACH related to transmitting UpPCH from the subframe that meets a certain relationship;

Step 15, if an effective response FPACH is detected in the expected WT subframe, then the random access is successful, otherwise step 16 is performed;

Step 16, if no effective response FPACH is detected within the expected WT subframe. The signature retransmission counter is decremented by 1, that is, M=M-1;

Step 17, judge the value of M, if M>0 continue to execute step 18, otherwise go to step 19;

Step 18, after a random delay, adjust the transmission time and transmission power P=P+ΔP (the transmitted power cannot exceed the value indicated by the network side through signaling), and return to step 13 for execution;

Step 19, report a random access failure to the MAC sublayer.

In the above step 13, after the UE transmits the uplink pilot code, the Node B will perform uplink pilot code detection in the next WT subframe, that is, synchronous detection, and if the uplink pilot code is detected, it will send the uplink pilot code to the user terminal through FPACH Timing adjustment information, that is, sending the FPACH in step 14 above.

The random access detection method of the present invention is as follows:

[Embodiment 1] As shown in Figure 3, the random access detection method of the first embodiment of the present invention includes the following steps:

Step 101, start;

Step 102, determining threshold values Pm and Pd according to experimental or simulation results;

Step 103, the base station performs shift correlation with the received uplink pilot code signal sent by the random access user terminal and the 8 uplink pilot codes of the current cell to obtain 8 correlation power sequences;

Step 104, respectively seeking the maximum value of 8 correlation power sequences, forming a sequence Pmax with a length of 8, each value in the Pmax sequence represents the correlation output sequence of each pilot code;

Step 105, seeking the maximum value Max of the Pmax sequence;

Step 106, making i=1, Pmax(i) corresponds to the i-th Pmax sequence value, that is, the i-th pilot code correlation power sequence;

Step 107, judging whether Pmax(i) is greater than the threshold value Pm, if greater then proceed to step 108, otherwise jump to step 110;

Step 108, subtracting Max from Pmax(i), judging whether the obtained difference is less than a given threshold value Pd, if established, continue to execute step 109, otherwise jump to step 110;

Step 109, judging that the corresponding i-th uplink pilot code sequence is a pilot code sequence selected by a user terminal, and proceeding to step 111 for execution;

Step 110, judging that the i-th uplink pilot code cannot be successfully accessed (that is, no user selects the pilot code for access), and proceeds to step 111;

Step 111, let i=i+1;

Step 112, if i is greater than 8, then continue to execute step 113, otherwise jump to step 207 for execution;

Step 113, updating the threshold value;

Step 114, this detection ends.

Among the above steps, step 103 can be realized by passing the signal received by the antenna through a matched filter, and step 113 can also be eliminated, that is, keep the threshold value unchanged, or adjust the threshold value adaptively as required.

[Embodiment 2] Alternatively, as shown in Figure 4, according to the random access detection method according to the second embodiment of the present invention, the steps are as follows:

Step 201, setting the threshold values Pm and Pd according to the experimental or simulation results;

Step 202, using the 8 uplink pilot codes of the current cell to perform shift correlation with the signal received by the antenna, that is, the uplink pilot code signal sent by the random access user, to obtain 8 correlation power sequences;

Step 203, respectively calculating the maximum power value of the correlation power sequence of each pilot code, forming a maximum power sequence Pmax with a length of 8, and each value in the Pmax sequence represents the correlation output sequence of each pilot code;

Step 204, seeking the maximum value Max in the maximum power sequence Pmax;

Step 205, find all values greater than Pm in the maximum power sequence Pmax, form a sequence P1 with a length of L, and find the pilot code sequence corresponding to P1;

Step 206, if L is greater than 0, that is, P1 exists, continue to execute step 207, otherwise skip to step 210;

Step 207, subtracting Max from the value in the sequence P1, finding all values in the difference that are smaller than the threshold value Pd, forming a sequence P2 with a length of M, and finding the pilot code sequence corresponding to P2;

Step 208, if M is greater than 0, that is, P2 is established, continue to execute step 209, otherwise execute step 210;

Step 209, determining that the pilot code sequence corresponding to P2 is the pilot code sequence selected by the user terminal;

Step 210, judging that no pilot code access request is detected;

Step 211, this detection ends.

In the first and second embodiments above, the selection of the threshold value has a great influence on the detection effect. From the above random access process, it can be seen that each UE will resend the access request after a certain random time delay after initiating a random access without receiving a response. Therefore, this access feature can also be combined by adjusting the threshold For example, preferably, the threshold value Pd is close to 0, so that only one UE's request is responded to in a single subframe, and a good detection effect can also be obtained.

[Embodiment 3] Alternatively, as shown in Figure 5, according to the random access detection method of the third embodiment of the present invention, the steps are as follows:

Step 301, setting the threshold value Pm;

Step 302, using the 8 uplink pilot codes of the current cell to perform shift correlation with the signal received by the antenna, that is, the uplink pilot code signal sent by the random access user, to obtain 8 correlation power sequences;

Step 303, seeking the maximum power value of each correlation power sequence, forming a maximum power sequence Pmax with a length of 8, each value in the Pmax sequence represents the correlation output sequence of each pilot code;

Step 304, seeking the maximum value Max in the maximum power sequence Pmax, and the pilot code sequence corresponding to the Max value;

Step 305, judging whether the Max value is greater than the value of Pm, if established then continue to execute step 306, otherwise execute step 307;

Step 306, judging that the pilot code sequence corresponding to Max is a pilot code sequence selected by a user terminal;

Step 307, judging that no pilot code access request is detected;

Step 308, the current detection ends.

The method of the above-mentioned third embodiment is preferably suitable for single-user detection, but since each UE will resend the access request after a certain random time delay after initiating a random access without receiving a response, it can also be combined with this method Such access characteristics, using the method of the third embodiment in each subframe naturally realizes the detection of multiple access users.

In each of the above-mentioned embodiments, because when there is a pilot code access, it is reflected that the maximum value of the relevant power of the pilot code should be significantly greater than the maximum value of the other pilot code-related power sequences, so this feature can be used for pilot code detection. The determination of the threshold value is very important for the correctness of synchronous detection. The threshold value can be determined through simulation and experiment; the method of adaptively changing the threshold value can also be adopted: according to each detection result or several subframes for a period of time The noise-related power and signal-related power are calculated respectively based on the detection results in the system, and the threshold value is adaptively adjusted accordingly, so that the threshold value is more reasonable and can be adaptively changed according to changes in the environment.

Of course, the detection method of the present invention can also be applied to systems with other numbers of pilot code sequences, and can be used alone to detect single-user or multi-user access pilot code detection processes; it can also be combined with existing detection pilots The judgment condition of code collision realizes the detection process of multi-user collision. The existing random access detection algorithm requires three judgment conditions for judgment, and the method can reduce certain judgment steps and judgment conditions, and can realize the same random access function and similar system performance, and the implementation is simpler.

Of course, the present invention can also have other various embodiments, and those skilled in the art can make various corresponding changes and deformations according to the present invention without departing from the spirit and essence of the present invention, but these corresponding Changes and deformations should all belong to the protection scope of the appended claims of the present invention.

Claims (9)

1. the detection method that user terminal inserts at random is used for the TDD mode wireless communication system, it is characterized in that, comprising:

Step S1, it is relevant that the ascending pilot frequency sign indicating number sequence that the access user terminal at random that receives is sent and N ascending pilot frequency sign indicating number sequence of user terminal affiliated subdistrict are shifted respectively, obtains N related power sequence, and N is a positive integer;

Step S2 calculates the maximum power value in each related power sequence, and forming length is the maximum power sequence of N, and calculates the maximum in the described maximum power sequence;

Step S3, select first threshold value and second threshold value, difference respectively and between maximum in described maximum power value and the maximum power sequence and the maximum power value, compare judgement, when satisfying condition, judge the ascending pilot frequency sign indicating number sequence that corresponding ascending pilot frequency sign indicating number sequence is a user terminal selecting in the current step S3 decision operation and determine this pilot code sequence.

2. the detection method that user terminal according to claim 1 inserts at random is characterized in that, described step S3 comprises:

Step S3.11 sets first threshold value and second threshold value;

Step S3.12, ask in the described maximum power sequence maximum power value greater than first threshold value, forming length is the sequence P1 of L, and asks the ascending pilot frequency sign indicating number sequence of sequence P1 correspondence, as infructescence P1 existence then continuation execution in step S3.13, otherwise judge that detecting the user does not insert request;

Step S3.13, maximum in the described maximum power sequence and the value among the sequence P1 are subtracted each other, ask in the difference all less than the value of second threshold value, forming length is the sequence P2 of M, and ask the ascending pilot frequency sign indicating number sequence of sequence P2 correspondence, if M is that sequence P2 exists greater than 0 then judges that the ascending pilot frequency sign indicating number sequence of sequence P2 correspondence is the ascending pilot frequency sign indicating number sequence of user terminal selecting, otherwise judges that not detecting the user inserts request.

3. the detection method that user terminal according to claim 1 inserts at random is characterized in that, described step S3 comprises:

Step S3.21 sets first threshold value and second threshold value;

Step S3.22 selects a related power sequence, obtains a corresponding ascending pilot frequency sign indicating number sequence simultaneously;

Whether step S3.23, the maximum power value of judging selected related power sequence greater than first threshold value, if set up then continue execution in step S3.24, otherwise judges do not have the user to select the ascending pilot frequency sign indicating number sequence described in the step S3.22;

Step S3.24, calculate the maximum in the described maximum power sequence and the difference of the maximum power value among the step S3.23, judge that whether the difference that obtains is less than second threshold value, if set up then the ascending pilot frequency sign indicating number sequence described in the determination step S3.22 is the ascending pilot frequency sign indicating number sequence of a user terminal selecting, otherwise judge do not have the user to select described ascending pilot frequency sign indicating number sequence.

4. the detection method that user terminal according to claim 3 inserts at random, it is characterized in that the judgement of described step S3.23 is false, perhaps the judgement among the S3.24 is set up or when being false, all return step S3.22, intact until whole related power sequence selection.

5. the detection method that inserts at random according to claim 2 or 4 described user terminals, it is characterized in that, when the described second threshold value value near 0 the time, next subframe after step S3.13 or S3.24 carry out is returned step S1, and is intact until the ascending pilot frequency sign indicating number series of operations of whole user terminals.

6. the detection method that inserts at random according to claim 2 or 3 described user terminals is characterized in that, described first or second threshold value by experiment or simulation result determine.

7. the detection method that inserts at random according to claim 2 or 4 described user terminals is characterized in that also further execution in step: adjust first threshold value and second threshold value adaptively according to testing result.

8. the detection method that user terminal according to claim 7 inserts at random is characterized in that, described set-up procedure is by calculating and analyzing the noise related power and signal correction power is finished.

9. the detection method that user terminal according to claim 1 inserts at random is characterized in that, described cell uplink pilot code sequence number N is 8.

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