CN100401660C - Detection method of 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

The detection method that a kind of user terminal inserts at random

Technical field

The present invention relates to wireless communication technology, particularly relate to a kind of user terminal (UE) method of access to wireless communication system at random that in TDD mode (TDD) wireless communication system, detects.

Background technology

In the TD-SCDMA system, what the synchronous detecting that user terminal inserts at random referred to is exactly the process of setting up uplink synchronous between one or more user terminals and the base station.

After the user terminal start, must at first set up down-going synchronous with sub-district (cell).Only under the condition of down-going synchronous, could begin to set up uplink synchronous.

The foundation of uplink synchronous is to finish in the process that user terminal inserts at random conversely speaking.The foundation of uplink synchronous relates to ascending pilot channel (UpPCH) and Physical Random Access Channel (PRACH).Although user terminal can (Node B) receive downstream signal from the base station, but the distance to Node B is still uncertain, this causes asynchronous up emission between the different user terminals, in order to reduce the interference of consequent business time-slot, the emission first of uplink direction is carried out at this special time slot of uplink pilot time slot (UpPTS).

Consult Fig. 1, the foundation of uplink synchronous generally comprises following steps: step 1, and user terminal sends specific ascending pilot frequency coded signal (SYNC-UL sequence) at uplink pilot time slot by up link; Step 2, Node B detects the SYNC-UL sequence in search window (comprising protection time slot GP and uplink pilot time slot UpPTS) after, estimate the time, send adjustment information to user terminal, step 2 is finished by in the individual subframe of WT (1～4, maximum is 4) of physical access channel (FPACH) after step 1; Step 3, user terminal are adjusted the launch time when launching next time according to the adjustment information of Node B, set up uplink synchronous behind the transmission PRACH.Uplink synchronous when the uplink synchronous process also can be used for uplink loss rebulids.

In above-mentioned steps; synchronous detecting is discerned the SYNC_UL sequence by analyzing the antenna data that obtains in protection time slot and the uplink pilot time slot; if detect an effective SYNC_UL sequence, simultaneous bias (SS) and power control (PC) instruction of then finishing the calculating of wave beam forming weight coefficient, FPACH generate and some measurement tasks.

Usually, the function of synchronous detecting can be divided into two parts: the SYNC_UL identification of signing, and comprises that antenna data obtains, matched filtering, signature identification and FPACH arrange; And parameter measurement, comprise that the SYNC_UL received power is measured, the wave beam forming weight coefficient is measured, FPACH power control (PC) instruction generates, the RACH interference power is measured and FPACH simultaneous bias (SS) instruction generates.

In above-mentioned functions, signature identification can be thought the core of whole Synchronous Detection, the algorithm that is adopted is directly connected to the performance that inserts at random, the quality that its corresponding user inserts the detection algorithm performance directly has influence on correctly access of radio network of user, and simultaneously wrong user inserts decline and the resource waste that (mistake when comprising no UE inserts and the mistake access the during collision of multi-user's ascending pilot frequency) directly causes systematic function.

Existing synchronization detecting method, particularly signature identifying method is as follows:

Usually, the ascending pilot frequency coded signal that each user terminal sends has good autocorrelation usually, the base station can utilize the correlation of pilot code, adopt the related operating method of multiple maturations such as direct sequence convolution (linear correlation) or matched filtering and detect the corresponding pilot code information that the user sends, detect the situation that user terminal inserts at random with this in conjunction with certain detection judgment condition.

Antenna data obtain and the matched filtering process as follows:

Antenna data obtains the data segment e that is used for determining the SYNC_UL place, and detection window comprises GP and UpPTS, promptly begins to finish to time slot 1 (TS1) original position from downlink pilot frequency channel (DwPTS) end position.The length of data segment is 256chips (promptly comprising the GP time slot of 96chips and the UpPTS time slot of 160chips), and the baseband receiving signals of process channel and additive noise can be expressed as:

$e\left(l\right)=h*s_{\mathrm{UL}}+n=\underset{i=1}{\overset{128}{\mathrm{\Σ}}}h\left(i\right)\·s_{\mathrm{UL}}(l-i)+n\left(l\right),$ 1＜l＜256(1)

Wherein h represents practical channel impulse response, S _ULRepresent a certain ascending pilot frequency sign indicating number, n is additive noise and interference, and symbol * represents the convolution process.

Can be expressed as through the tap related power sequence after the matched filtering of same ascending pilot frequency sign indicating number:

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

Bringing equation (1) into equation (2) can get:

$y\left(k\right)=\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\underset{i=1}{\overset{128}{\mathrm{\Σ}}}h\left(i\right)\·s_{\mathrm{UL}}(j+k-i)+\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·n(j+k)$

$=\underset{i=1}{\overset{128}{\mathrm{\Σ}}}h\left(i\right)\·\{\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·s_{\mathrm{UL}}(j+k-i)\}+\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·n(j+k)$

$=128\×\underset{i=1}{\overset{128}{\mathrm{\Σ}}}[h\left(i\right)\·\mathrm{\δ}(k-i)]+\underset{i=1}{\overset{128}{\mathrm{\Σ}}}\{h\left(i\right)\·[\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·s_{\mathrm{UL}}(j+k-i)\left]{|}_{k\≠i}\right\}+\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·n(j+k)$

(3)

Make the channel impulse response tap in the following formula $h\left(k\right)=128\×\underset{i=1}{\overset{128}{\mathrm{\Σ}}}[h\left(i\right)\·\mathrm{\δ}(k-i)]$ , and make noise and disturb tap

$h_n\left(k\right)=\underset{i=1}{\overset{128}{\mathrm{\Σ}}}\{h\left(i\right)\·[\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·s_{\mathrm{UL}}(j+k-i)\left]{|}_{k\≠i}\right\}+\underset{j=1}{\overset{128}{\mathrm{\Σ}}}{s}_{\mathrm{UL}}\left(j\right)\·n(j+k)---\left(4\right)$

Then equation (3) can be simplified to:

y(k)＝h(k)+h _n(k) (5)

Note if the ascending pilot frequency coded signal satisfies good autocorrelation performance, promptly when τ ≠ 0 ACF (τ)=0 being arranged, then second in the equation (3) can be approximately 0.

The signature identifying: signature identification detects judgement to the tap related power sequences y (k) in the equation (3) exactly, is satisfying under the situation of certain testing conditions, and just judging has SYNC_UL to insert.

So testing conditions is particularly important for the correct judgement of SYNC_UL, the existing detection algorithm that inserts at random needs three kinds of judgment condition to adjudicate usually, and efficient has much room for improvement.

Summary of the invention

The detection method that provides a kind of user terminal to insert at random is provided technical problem to be solved by this invention, can realize the detection that one or more user terminals insert at random rapidly and accurately, can simplify existingly insert detection algorithm at random, implement more simple and convenient.

In order to address the above problem, the detection method that user terminal of the present invention inserts at random comprises the steps:

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

Step S2 calculates the maximum power value in described 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 selects threshold value, with described maximum power value, the perhaps maximum in the maximum power sequence, 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 and determine this pilot code sequence.

Described step S3 specifically 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 a user terminal selecting, otherwise judges that not detecting the user inserts request; Perhaps

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

Step S3.22, selecting a related power sequence is a corresponding ascending pilot frequency sign indicating number sequence;

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 this ascending pilot frequency sign indicating number sequence;

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 judge the ascending pilot frequency sign indicating number sequence that this ascending pilot frequency sign indicating number sequence is a user terminal selecting, promptly determine the pilot code sequence that the user is sent, otherwise judge do not have the user to select this ascending pilot frequency sign indicating number sequence.

The judgement of above-mentioned steps S3.23 is false, and perhaps the judgement among the S3.24 is set up or when being false, all returned step S3.22, and is intact until whole related power sequence selection.

Above-mentioned steps S3 can also comprise:

Step S3.31 sets first threshold value;

Step S3.32, judge whether the maximum in the maximum power sequence satisfies greater than first threshold value, if set up then judge that the pairing pilot code sequence of this maximum is the pilot code sequence that a user terminal sends, otherwise judge that receiving the ascending pilot frequency sign indicating number does not promptly have the user to initiate to insert at random request;

After the above-mentioned steps S3, also further execution in step: upgrade first and/or second threshold value (optional) adaptively according to testing result.

The number N of above-mentioned ascending pilot frequency sign indicating number sequence is specially 8.

Detection method of the present invention can realize that single user detects or Multiuser Detection by adjusting threshold value, also can carry out the testing process of multi-user's access interference in conjunction with existing detection conflict resolution condition, reduced judgment condition compared with existing detection algorithm, the step that realizes also obviously reduces, and implements more easy than existing detection algorithm.

Description of drawings

The process schematic diagram that Fig. 1 inserts at random for user terminal;

Fig. 2 is the flow chart of user terminal random access procedure of the present invention;

Fig. 3 inserts the flow chart of testing process at random for first embodiment of the invention;

Fig. 4 inserts the flow chart of testing process at random for second embodiment of the invention;

Fig. 5 inserts the flow chart of testing process at random for third embodiment of the invention.

Embodiment

Below in conjunction with accompanying drawing specific embodiments of the invention are described in further detail.

The detection method that user terminal according to the present invention inserts at random, before random access procedure, user terminal need insert preparation at random, and (rrc layer) receives following parameter information from the upper strata:

A. 8 of this user terminal sub-district of living in ascending pilot frequency sign indicating numbers;

B. ascending pilot frequency sign indicating number (signature) maximum number of retransmissions M;

C. user's terminal transmitting power is adjusted step delta P;

D. user terminal waits for that network sends the maximum wait number of subframes WT that signature is recognized to one, and the WT value is 1～4, is defaulted as 4 subframes usually.

Afterwards, as shown in Figure 2, user terminal inserts at random, specifically comprises the steps:

Step 11 is provided with signature retransmission counter M, power adjustment step delta P and WT number of sub frames;

Step 12 is determined Initial Trans P and launch time;

Step 13, ascending pilot frequency sign indicating number of picked at random from 8 given ascending pilot frequency sign indicating numbers is to launch Initial Trans P and launch time that step 12 is determined;

Step 14 is listened to relevant FPACH behind the emission ascending pilot frequency sign indicating number (signature), obtains network validation from WT subframe subsequently, and UE will read the FPACH relevant with launching UpPCH from the subframe that satisfies certain relation;

Step 15 if detect effective response FPACH in the WT subframe of expection, then inserts successfully at random, otherwise execution in step 16;

Step 16 does not subtract 1 if detect effective response FPACH. signature retransmission counter in the WT subframe of expection, i.e. M=M-1;

Step 17 is judged the M value, if execution in step 18 is continued in M＞0, otherwise goes to step 19;

Step 18 is adjusted launch time and transmitting power P=P+ Δ P (emitted power can not surpass the numerical value of network side by the signaling indication) behind a random delay, turn back to step 13 again and carry out;

Step 19 is reported once access failure at random to media access control sublayer.

After above-mentioned steps 13, UE emission ascending pilot frequency sign indicating number, Node B carries out the ascending pilot frequency sign indicating number and detects in ensuing WT subframe, it is synchronous detecting, if detect the ascending pilot frequency sign indicating number, then send timing adjustment information by FPACH to user terminal, also promptly send the FPACH in the above-mentioned steps 14.

Random access detecting method of the present invention is as follows:

[embodiment 1] as shown in Figure 3, the random access detecting method of first embodiment of the invention comprises the steps:

Step 101, beginning;

Step 102 is determined threshold value Pm and Pd according to experiment or simulation result;

It is relevant that the ascending pilot frequency coded signal that access user terminal at random that step 103, base station will receive sends and 8 ascending pilot frequency sign indicating numbers of current area are shifted respectively, obtains 8 related power sequences;

Step 104 is asked the maximum of 8 related power sequences respectively, forms length and be 8 sequence Pmax, and each value in the Pmax sequence is represented the relevant output sequence of each pilot code;

Step 105 is asked the maximum Max of Pmax sequence;

Step 106 makes i=1, and Pmax (i) also is i pilot code related power sequence corresponding to i Pmax sequential value;

Whether step 107 judges Pmax (i) greater than threshold value Pm, if greater than would continue execution in step 108, otherwise skip to step 110;

Step 108 is subtracted each other Max and Pmax (i), whether judges the difference obtain less than given threshold value Pd, if set up then continue execution in step 109, otherwise skips to step 110;

Step 109 judges that corresponding i ascending pilot frequency sign indicating number sequence is the pilot code sequence of a user terminal selecting, and goes to step 111 execution;

Step 110 judges that this i ascending pilot frequency sign indicating number can not successfully insert (promptly not having the user to select this pilot code to insert), and continues execution in step 111;

Step 111 makes i=i+1;

Step 112 if i greater than 8, then continues execution in step 113, is carried out otherwise skip to step 207;

Step 113 is upgraded threshold value;

Step 114, this detects end.

In the above-mentioned steps, step 103 can realize that through matched filter step 113 also can be removed, and promptly keeps threshold value constant, or adaptive as required adjustment threshold value by the signal that antenna is received.

[embodiment 2] or, as shown in Figure 4, according to the random access detecting method of second embodiment of the invention, step is as follows:

Step 201 is provided with threshold value Pm and Pd according to experiment or simulation result;

Step 202 promptly inserts ascending pilot frequency coded signal that the user sends at random with signal that antenna receives respectively with 8 ascending pilot frequency sign indicating numbers of current area and is shifted relevantly, obtains 8 related power sequences;

Step 203 is calculated the maximum power value of the related power sequence of each pilot code respectively, forms length and be 8 maximum power sequence Pmax, and each value in the Pmax sequence is represented the relevant output sequence of each pilot code;

Step 204 is asked the maximum Max among the maximum power sequence Pmax;

Step 205 is asked all values greater than Pm among the maximum power sequence Pmax, and forming length is the sequence P1 of L, and asks the pilot code sequence of P1 correspondence;

Step 206 if L is that P1 exists then continues execution in step 207 greater than 0, otherwise skips to step 210;

Step 207 is subtracted each other the value among Max and the sequence P1, asks in the difference all less than the value of threshold value Pd, and forming length is the sequence P2 of M, and asks the pilot code sequence of P2 correspondence;

Step 208, if M is that P2 sets up then continues execution in step 209 greater than 0, otherwise execution in step 210;

Step 209 judges that the pilot code sequence of P2 correspondence is the pilot code sequence of user terminal selecting;

Step 210 judges that not detecting pilot code inserts request;

Step 211, this detects end.

Among above-mentioned first and second embodiment, the selection of threshold value is bigger to detecting influential effect.By above-mentioned random access procedure as can be seen each UE all can behind certain random delay, resend the request of access after not meeting with a response initiating once to insert at random, so also can be in conjunction with this access characteristic, by adjusting threshold value, such as preferable, make threshold value Pd be close to 0, make the request that only responds a UE in the single subframe, also can well be detected effect.

[embodiment 3] or, as shown in Figure 5, according to the random access detecting method of third embodiment of the invention, step is as follows:

Step 301 is provided with threshold value Pm;

Step 302 promptly inserts ascending pilot frequency coded signal that the user sends at random with signal that antenna receives respectively with 8 ascending pilot frequency sign indicating numbers of current area and is shifted relevantly, obtains 8 related power sequences;

Step 303 is asked the maximum power value of each related power sequence, forms length and be 8 maximum power sequence Pmax, and each value in the Pmax sequence is represented the relevant output sequence of each pilot code;

Step 304 is asked the maximum Max among the maximum power sequence Pmax, and the corresponding pilot code sequence of Max value;

Step 305 is judged the Max value whether greater than the value of Pm, if set up then continue execution in step 306, otherwise execution in step 307;

Step 306 judges that the pilot code sequence of Max correspondence is the pilot code sequence of a user terminal selecting;

Step 307 judges that not detecting pilot code inserts request;

Step 308, this detects end.

Single user that is applicable to that the method for above-mentioned the 3rd embodiment is preferable detects, but because each UE is initiating can to resend the request of access after once access does not meet with a response at random behind certain random delay, so also can be in conjunction with this access characteristic, use the very natural a plurality of access of the realization users' of the method for the 3rd embodiment detection respectively in each subframe.

In the various embodiments described above and since when pilot code inserts, embody the maximum of this pilot code related power should be obviously peaked greater than all the other pilot code related power sequences, so can utilize these characteristics to carry out the detection of pilot code.Determining of threshold value is most important for the correctness of synchronous detecting, can determine threshold value by emulation and experiment; Also can adopt the mode of adaptively changing threshold value: according to the testing result in each testing result or several subframes of a period of time, calculating noise related power and signal correction power and adjust threshold value thus adaptively respectively make the thresholding value more rationally can be according to the adaptive change of the variation of environment like this.

The system that detection method of the present invention can also be applicable to other quantity pilot code sequence certainly can use separately, is used for detecting the pilot code testing process of single user or multi-user's access; Also can realize the testing process of multi-user conflict in conjunction with the judgment condition of existing detection pilot code conflict.The existing detection algorithm that inserts at random needs three kinds of judgment condition to adjudicate, and adopts this method can reduce certain decision steps and judgment condition, can realize same access function at random and close systematic function and implement more simple.

Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim 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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