CN1937463A - Shift sequence detecting method for CDMA system - Google Patents

Abstract

The method includes steps: obtaining the position of related noise from the position of the available path, calculating average noise, producing noise judgment threshold and testing the discontinue transfer. When the system configuration is in the state of discontinue transfer, the method tests this state. When the system configuration is not in the state of discontinue transfer, it calculates the availability of all estimate windows except the 1sf one in all physical coding combination transfer channel (PCCTC) of the aim user. It utilizes the info of the accurate path relative delay and the info of PCCTC of the aim user to test accurately the info of active training sequence distributed to the aim user. Then according to the info of training sequence of the aim user, it calculates the info of active training sequence of other users to test the info of other users. This is valuable to realize combination test algorithm.

Description

Shift sequence detection method in CDMA system

Technical Field

The invention relates to the technical field of wireless communication, in particular to a method for detecting a shift bit sequence in a time division synchronous code division multiple access system.

Background

In a receiving device of a time division synchronous code division multiple access system, different detection methods are provided for a shift sequence in the whole system. As shown in fig. 1, the allocation method of the shifted sequences is according to the setting of the network layer, there are three training sequence allocation methods of the system, a DEFAULT allocation method (DEFAULT), a COMMON allocation method (COMMON) and a user specified allocation method (ue specfic), and known information that can be obtained by the system is different among the three different shifted sequence allocation methods, for example, the system broadcasts corresponding channelization codes in the DEFAULT allocation method, and the channelization codes and shifted sequences of the serving cell have a one-to-one correspondence relationship; the higher layer assigns channelization codes and shifted sequences to users in a user-specific manner. The system can obtain different known information under different shifting sequence allocation modes, so that the subsequent shifting sequence detection algorithm also changes.

Accurately obtaining the shift training information has a significant impact on the demodulation performance of the entire system. The system allocates one or more shift training sequences to users according to the service requirements, and the base station sends configuration information corresponding to the transmission requirements of the services, and the terminal user can exactly calculate the information of the shift training sequences used by the related services according to the configuration information, but the configuration information is transmitted in the first radio frame in a transmission interval, and the exact shift training sequence information cannot be obtained before the configuration information is obtained, so that at least in the first radio frame of a certain transmission time interval, the target user needs to detect the condition of the activated shift training sequences sent by the base station, and the information is necessary in the subsequent demodulation process. Meanwhile, estimation can be performed from the effective shift sequence, so that the detection condition of the shift training sequence directly affects subsequent demodulation, when the effective shift training sequence is missed, data loss is directly caused, so that the performance of a subsequent decoding module is seriously deteriorated, the performance of a joint detection module is also deteriorated, and similarly, when the false detection condition occurs, the performance of subsequent joint detection is also deteriorated, and the waste of system operation resources is caused. Especially, when a target user is allocated with multiple physical code combined transmission channels, how to accurately judge the shifted training sequence allocated by the target user is very important for the whole receiving system, and the performance of the system will have a great influence on the performance of the receiving and demodulating system.

Since the conventional shift sequence detection method only uses a threshold judgment method, the detection of the shift training sequence cannot be accurately performed. When the power value of a certain shift sequence meets a certain threshold, the shift sequence is considered to be effective, and when a plurality of shift sequences are activated, due to the detection of other shift sequences, the detection of a certain shift sequence fails due to the interference among the shift sequences.

Therefore, the conventional detection algorithm cannot enable the target user to acquire the relative delay information of the relevant known path, so that the shifted training sequence information of the system cannot be accurately detected.

Disclosure of Invention

The invention aims to provide a method for detecting a shift sequence in a time division synchronous code division multiple access system, which can calculate the information of the activated training sequences of a target user and other users according to the relative time delay of an effective path and the information of the training sequence of the target user so as to accurately detect the information of other users and be beneficial to realizing a joint detection algorithm of a receiving device.

In order to achieve the purpose, the invention can be realized by the following technical scheme:

the invention provides a shift sequence detection method in a time division synchronous code division multiple access system, which comprises the following steps:

A. obtaining the position of corresponding noise according to the position of the effective path, then calculating average noise according to the noise position pair, and generating a noise judgment threshold;

B. detecting discontinuous transmission, and when the system is configured to be in a discontinuous transmission state, detecting the discontinuous transmission state; when the system configuration does not use the discontinuous transmission state, directly executing the step C;

if the system is not in the discontinuous transmission state, executing the step C;

if the system is in the discontinuous transmission state, finishing the subsequent operation of the current channel;

C. and calculating whether other estimation windows except the first estimation window in each physical code combined transmission channel of the target user are effective.

Preferably, the method further comprises:

D. and after the detection of the estimation window of the target user is finished, estimating the estimation windows of other users.

The step A specifically comprises the following steps:

a1. calculating the average noise power:

determining the position of the noise path according to the path information phi of the effective path position, and calculating to obtain the position information of the noise path

Simultaneously calculating the average value of the noise power at the noise position and the average noise P in the frame based on the obtained channel estimate DP_noise：

<math> <mrow> <msub> <mi>P</mi> <mi>noise</mi> </msub> <mo>=</mo> <mfrac> <mrow> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <mrow> <mo>(</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>W</mi> </munderover> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>&times;</mo> <msub> <mi>NoiseMask</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>)</mo> </mrow> </mrow> <mrow> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>W</mi> </munderover> <msub> <mi>NoiseMask</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>;</mo> </mrow> </math>

NoiseMask, (k) represents the noise position of the kth sampling point of the tth shift training sequence obtained by the path information, and the position of the noise generated by phi;

DP_t(k) representing the channel estimation module value of the kth sampling point of the t-th shift training series;

phi is the position of the effective path;

w represents the length of the channel estimation window considering the channel oversampling multiple speed;

t is a set of shifted training sequences of different windows selected for calculating noise;

a2. calculating detection threshold Thr of discontinuous reception_DTX：

Thr_DTX＝P_noise ^*K_DTX；

Wherein, K_DTXIs a preset threshold.

Preferably, when averaging the noise power at the noise position, the partial noise position is averaged.

Preferably, the minimum value of T is 1.

Said K_DTXThe dynamic change can be obtained through a field test or simulation method or can be self-adapted according to the field condition.

The detecting of the discontinuous transmission state specifically includes:

calculating the maximum value P of the channel estimation value DP in the first estimation window of each physical coding combined transmission channel (CCTrCH) at the position of the effective path_max ^First：

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>First</mi> </msubsup> <mo>=</mo> <mrow> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>first</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </mrow> </math>

Wherein, first represents the number of the first estimation window of the physical code combined transmission channel;

the method also comprises the following steps of judging the validity of the initial window:

judging the maximum value P of the first estimation window of each physical code combined transmission channel of all target users_max ^FirstWhether it is not less than the threshold Thr_DTX；

If p is_max ^first＞Thr_DTXLetter ofWhen the effective receiving signal exists, executing the step C;

and when the system is in the discontinuous transmission state, closing the subsequent execution operation.

Preferably, the detection of the effectiveness of the other estimation windows of the target user is implemented by the following steps:

c1. searching the maximum estimation value of each estimation window in the target user: calculating the maximum value of the channel estimation value DP in the first estimation window of the current physical coding combination transmission channel:

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>First</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>first</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

wherein, the fist represents the number of the first estimation window of the physical code combined transmission channel;

c2. normalization operation of channel estimation of target user:

$p_{\mathrm{Code}}=P_{\max }^{\mathrm{First}}/\sqrt{N_c;}$

wherein N is_cIs a normalization factor; p_CodeIs the normalized maximum value;

c3. computing PC_odeCorresponding normalized maximum threshold Th _ X_OwnMA：

Th_X_OwnMA＝P_Code ^*TO_{wn_max}；

Wherein, T_{Own_max}Is a set threshold;

c4. calculating detection threshold Th of target user residual estimation window_ownCalculating the final detection threshold except the first estimation window in the current coding combination transmission channel;

c5. calculating the maximum value of the residual estimation windows of the target user, namely calculating the maximum value P of the path positions marked by the path information phi of other estimation windows except the first estimation window in the current code combined transmission channel_t：

<math> <mrow> <msub> <mi>P</mi> <mi>t</mi> </msub> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

Wherein, t belongs to OwnCCTrCH, which distributes all possible estimation windows of the channel except the first estimation window for the current coding combined transmission channel of the target user;

c6. and (3) detecting the effectiveness of the residual estimation window of the target user: by comparing the maximum value P of the residual shifted training sequence estimation window in the current code combined transmission channel_tWhether greater than the threshold Th_ownTo determine whether the estimation window of the shifted training sequence is valid:

if P_t≥Th_ownIf yes, the estimation window of the t-th shift training sequence is considered to be effective;

c7. target user activation estimation window correction: if a certain estimation window of a coded combined transmission channel with a large sequence number is detected to be effective, the estimation window with the sequence number smaller than the number of the estimation window is considered to be effective;

c8. combining the normalized channel estimates of all activated shifted training sequence estimation windows through a certain coded composite transmission channel, and calculating the normalized channel estimate of a certain shifted training sequence of the certain coded composite transmission channel:

<math> <mrow> <msub> <mi>codeDP</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <mfrac> <mrow> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <msqrt> <msub> <mi>N</mi> <mi>t</mi> </msub> </msqrt> </mfrac> <mo>;</mo> </mrow> </math>

wherein, CodedP_i(k)_tNormalizing the channel estimation value for the k point of the shift training series of the ith coding combination transmission channel;

N_tnormalized channelization code number for the t-th shifted training series;

t is a shift training sequence set of the ith code combined transmission channel of the target user;

c9. target user channel estimation normalization: when the target user occupies multiple coded combined transmission channels, the normalized channel estimates CodeDP of the target user for all coded combined transmission channels are averaged, and the normalized combined channel estimate of the final activated channel estimate is calculated:

<math> <mrow> <msub> <mi>codeDP</mi> <mi>own</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <msub> <mi>N</mi> <mrow> <mi>CCTrCH</mi> <mo>_</mo> <mi>Num</mi> </mrow> </msub> </munderover> <msub> <mi>codeDP</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <msub> <mi>N</mi> <mrow> <mi>CCTrCH</mi> <mo>_</mo> <mi>Num</mi> </mrow> </msub> </mfrac> <mn>。</mn> </mrow> </math>

the normalization factor N_cThe number of the activated channelisation codes corresponding to each shift training sequence is counted in the normalization factor according to the channelisation codes which are specified by the protocol and are allocated to the target user.

The T is_{Own_max}Dynamic changes can be obtained through field tests or simulation methods or can be self-adapted according to field conditions;

the detection threshold Th of the target user residual estimation window_ownFor normalized maximum threshold Th _ X_OwnMAOr discontinuous reception threshold Thr_DTX。

Preferably, the estimating the estimation windows of the other users is implemented by the following steps:

detecting whether the number of estimation windows supported by the current system is completely distributed to a target user, if so, ending; otherwise, the following steps are continuously executed:

a normalized maximum value for the target user is calculated,

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>Own</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>codeDP</mi> <mi>own</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

calculating the maximum threshold of each estimation window of other users:

${\mathrm{Th}\_X}_{\mathrm{MA}}=P_{\max }^{\mathrm{Own}}*T_{\max };$

wherein, T_maxA preset threshold for detecting the maximum value of the estimation window of other users;

determining the shift sequence detection threshold of other users and setting the threshold at the normalized maximum value Th _ X_MAAnd a threshold Thr for discontinuous reception_DTXThe larger one of them, or any one of them, namely:

Th＝max(Th_X_MA，Thr_DTX)；

or Th _ X_MA；

Or Th ═ Thr_DTX；

Calculating maximum value of estimation window of shifted training sequence of other users

$P_t=\underset{k=\{1:W\}}{\max }\left({\mathrm{DP}}_t\left(k\right)\right);$

Wherein, t _ OwnCCTrCH, said OwnCCTrCH is all possible estimation windows of the channel of the estimation window except all coded combined transmission channel allocation of the target user;

for other users: if P_t≥Th_ownThen the estimation window of the shifted training sequence is valid.

Preferably, the shift sequence detection threshold Th of the other users is a normalized maximum threshold Th _ X_MAOr discontinuous reception threshold Thr_DTX。

In summary, the present invention utilizes accurate information of path relative delay to assist the detection of the related shift sequence, and simultaneously fully utilizes the information of the physical coding combination transmission channel of the target user to accurately detect the information of the active training sequence allocated to the target user, and simultaneously calculates the information of the active training sequence of other users according to the information of the training sequence of the target user, so as to accurately detect the information of other users, which is beneficial to the realization of the joint detection algorithm of the receiving apparatus.

Drawings

FIG. 1 illustrates an allocation pattern of training sequences and a corresponding detection method in a TD-SCDMA system;

FIG. 2 is a flow chart of a shifted sequence detection method according to an embodiment of the present invention;

FIG. 3 is a flowchart of the steps of calculating the average noise power and noise threshold according to an embodiment of the present invention;

FIG. 4 is a flowchart of the detection procedure of the discontinuous transmission status of the system in the default allocation mode according to the embodiment of the present invention;

FIG. 5 is a flowchart of the target user shifted sequence detection procedure in the default allocation mode according to an embodiment of the present invention;

fig. 6 is a flowchart of the shifted sequence detection procedure of other users in the default allocation mode according to an embodiment of the present invention.

Detailed Description

The invention will be further understood by reference to the following detailed description of specific embodiments in conjunction with the accompanying drawings.

As shown in fig. 2, the present invention provides a method for detecting a shifted sequence in a default allocation manner in a td-scdma system, which comprises the following steps:

step 1, calculating average noise power and generating a noise judgment threshold; as shown in fig. 3, the step 1 further includes the following steps:

step 1.1, calculating average noise power:

determining the position of the noise path according to the path information phi of the effective path position, and calculating to obtain the position information of the noise path

At the same time, the average noise P in the frame is calculated according to the obtained channel estimation DP_noise：

<math> <mrow> <msub> <mi>P</mi> <mi>noise</mi> </msub> <mo>=</mo> <mfrac> <mrow> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <mrow> <mo>(</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>W</mi> </munderover> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>&times;</mo> <msub> <mi>NoiseMask</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>)</mo> </mrow> </mrow> <mrow> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>W</mi> </munderover> <msub> <mi>NoiseMask</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>;</mo> </mrow> </math>

Wherein NoiseMask_t(k) Representing the noise position of the kth sampling point of the t-th shift training sequence obtained by the path information and the position of noise generated by phi;

Φ is the location of the active path;

DP_t(k) representing the channel estimation value of the kth sampling point of the t-th shift training series;

w represents the length of the channel estimation window taking into account the channel oversampling factor;

t is a set of shifted training sequences of different windows selected for calculating noise, and T is at least 1 in the system;

step 1.2, calculating detection threshold Thr of discontinuous reception_DTX：

Thr_DTX＝P_noise ^*K_DTX；

Wherein, K_DTXWhich is a preset threshold, can be obtained through field test and simulation methods.

Step 2, detection of discontinuous transmission (DRX): when the system is configured to be in a discontinuous transmission state, executing the step 3; otherwise, directly executing the step 4;

step 3, detection of the discontinuous transmission state of the system: if the system is not in the discontinuous transmission state, executing the step 4; if the system is in the discontinuous transmission state, finishing the subsequent operation of the current channel; as shown in fig. 4, the step 3 further includes the following steps:

step 3.1, maximum value search: calculating the maximum value P of the channel estimation values DP in the first estimation window of each physical coding combined transmission channel (CCTrCH)_max ^First：

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>First</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <mi>D</mi> <msub> <mi>P</mi> <mi>first</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

Wherein, first represents the number of the first estimation window of the physical code combined transmission channel; where k e Φ means that the maximum search will search in the valid set of paths Φ.

Step 3.2, judging the validity of the initial window: judging the maximum value P of the first estimation window of each physical code combined transmission channel of all target users_max ^FirstWhether the threshold Thr is not less than the threshold Thr calculated in the step 1.2_DTX；

If P_max ^First＞Thr_DTXIf the channel is considered to have effective received signals, skipping to execute the step 4;

otherwise, it is considered that no effective received signal arrives in the channel, i.e. the system is in a discontinuous transmission state, and the subsequent operation of the channel will be actively closed.

Step 4, calculating whether other estimation windows except the first estimation window are effective in each physical coding combined transmission channel of the target user; as shown in fig. 5, the step 4 further includes the following steps:

step 4.1, searching the maximum estimation value of each estimation window in the target user: calculating the maximum value of the channel estimation value DP in the first estimation window of the current physical coding combination transmission channel, which is identified by the position of the effective multipath:

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>First</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>first</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

wherein, first represents the number of the first estimation window of the physical code combined transmission channel;

step 4.2, normalization operation of channel estimation of the target user:

$p_{\mathrm{Code}}=P_{\max }^{\mathrm{First}}/\sqrt{N_c};$

wherein N is_cIs a normalization factor; p_CodeIs the normalized maximum value;

the normalization factor N_cI.e. the number of activated channelization codes for each shifted training sequence, it is calculated according to protocol 25.221.aa.2 description of 3 Gpp: the channelizing codes which are in accordance with the protocol and are allocated to the target user by the system at the same time are counted into a normalization factor;

step 4.3, calculate P_CodeCorresponding normalized maximum threshold Th _ X_OwnMA：

Th_X_OwnMA＝P_Code*T_{Own_max}；

Wherein, T_{Own_max}The threshold is a preset threshold, can be obtained by a field test and simulation method, and can also be self-adaptively and dynamically adjusted on the field;

step 4.4, calculating the detection threshold Th of the residual estimation window of the target user_ownI.e. calculating a final detection threshold in the current cctrch, except for the first estimation window, which may be at the normalized maximum threshold Th _ X_OwnMAAnd a threshold Thr for discontinuous reception_DTXThe larger one of them, or any one of them, namely:

Th_own＝max(Th_X_OwnMA，Thr_DTX)；

or Th_own＝Thr_DTX；

Or Th_own＝Th_X_OwnMA；

Step 4.5, calculating the maximum value of the residual estimation window of the target user, namely calculating the maximum value P of the path position marked by the path information phi of other estimation windows except the first estimation window in the current coding combined transmission channel_t：

<math> <mrow> <msub> <mi>P</mi> <mi>t</mi> </msub> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

Wherein, t belongs to OwnCCTrCH, which distributes all possible estimation windows of the channel except the first estimation window for the current coding combined transmission channel of the target user;

step 4.6, the effectiveness of the target user residual estimation window is detected: by comparing the maximum value P of the residual shifted training sequence estimation window in the current code combined transmission channel_tWhether it is greater than threshold Th calculated in step 3.4_ownTo determine whether the estimation window of the shifted training sequence is valid:

if P_t≥Th_ownIf yes, the estimation window of the t-th shift training sequence is considered to be effective;

and 4.7, activating estimation window correction by the target user: if a certain estimation window of a code combined transmission channel with a large middle sequence number is detected effectively, the estimation window with the number smaller than that of the estimation window is considered to be effective;

step 4.8, combining and normalizing the CCTrCH of the target user: combining the normalized channel estimates of all activated shifted training sequence estimation windows through a certain coded composite transmission channel, and calculating the normalized channel estimate of a certain shifted training sequence of the certain coded composite transmission channel:

<math> <mrow> <msub> <mi>codeDP</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <mfrac> <mrow> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <msqrt> <msub> <mi>N</mi> <mi>t</mi> </msub> </msqrt> </mfrac> <mo>;</mo> </mrow> </math>

wherein, CodedP_i(k)_tNormalizing the channel estimation value for the k point of the shift training series of the ith coding combination transmission channel;

N_tnormalized channelization code number for the t-th shifted training series;

t is a shift training sequence set of the ith code combined transmission channel of the target user;

step 4.9, target user channel estimation normalization: when the target user occupies multiple coded combined transmission channels, the normalized channel estimates CodeDP of the target user for all coded combined transmission channels are averaged, and the normalized combined channel estimate of the final activated channel estimate is calculated:

<math> <mrow> <msub> <mi>codeDP</mi> <mi>own</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <msub> <mi>N</mi> <mrow> <mi>CCTrCH</mi> <mo>_</mo> <mi>Nun</mi> </mrow> </msub> </munderover> <msub> <mi>codeDP</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <msub> <mi>N</mi> <mrow> <mi>CCTrCH</mi> <mo>_</mo> <mi>Num</mi> </mrow> </msub> </mfrac> <mn>。</mn> </mrow> </math>

step 5, after the detection of the estimation window of the target user is finished, the estimation windows of other users are detected;

as shown in fig. 6, the step 5 specifically includes the following steps:

step 5.1, other users are detected to be checked: detecting whether the number of estimation windows supported by the current system is completely distributed to a target user, if so, ending; if not, continuing to execute the step 5.2;

step 5.2, calculating the normalized maximum value of the target user, that is, calculating the maximum value of the normalized channel estimation of the target user in the identified effective path in step 4.9:

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>Own</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>codeDP</mi> <mi>own</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

step 5.3, calculating the maximum threshold of each estimation window of other users:

${\mathrm{Th}\_X}_{\mathrm{MA}}=P_{\max }^{\mathrm{Own}}*T_{\max };$

wherein, T_maxA preset threshold for detecting the maximum value of the estimation window of other users;

step 5.4, calculating the shift sequence detection threshold of other users, which can be at the most normalizedLarge threshold Th _ X_MAAnd a threshold Thr for discontinuous reception_DTXThe larger one of them, or any one of them, namely:

Th＝max(Th_X_MA，Thr_DTX)；

or Th _ X_MA；

Or Th ═ Thr_DTX；

Step 5.5, calculating the maximum value of the estimation windows of other users, namely calculating the maximum value identified in the effective path of the estimation windows of other shifted training sequences except the allocated estimation window of the current code combination transmission channel:

<math> <mrow> <msub> <mi>P</mi> <mi>t</mi> </msub> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>=</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

wherein, t _ OwnCCTrCH, said OwnCCTrCH is all possible estimation windows of the channel of the estimation window except all coded combined transmission channel allocation of the target user;

and 5.6, judging the effectiveness of other users: if P_t≥Th_ownThen the estimation window of the shifted training sequence is considered valid.

When the shifted training sequence mode is COMMON assignment mode (COMMON), the method is as follows:

a, obtaining the position of corresponding noise according to the position of an effective path, and then calculating the average noise power and a noise threshold according to the pair so as to calculate the average noise and generate a noise judgment threshold;

B. detection of discontinuous transmission: when the system is configured to be in a discontinuous transmission state, detecting the discontinuous transmission state, and judging whether the system is in a discontinuous transmission state;

wherein each substep of step a is consistent with a default pattern.

The step B specifically comprises the following steps:

b1. calculating the maximum value P of the channel estimation value DP at the position of the effective path in each estimation window of each physical coding combined transmission channel (CCTrCH)_max ^First：

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>U</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mi>U</mi> </munder> <mrow> <mo>(</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>U</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math> In the formula, U is the serial number of each estimation window;

b2. judging the first window validity: judging the maximum value P of the first estimation window of each physical code combined transmission channel of all target users_max ^UWhether it is not less than the threshold Thr_DTX；

If it is $P_{\max }^U>{\mathrm{Thr}}_{\mathrm{DTX}}$ Means that there is a valid shifted training sequence in the slot, e.g. if <math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>U</mi> </msubsup> <mo>&le;</mo> <msub> <mi>Thr</mi> <mi>DTX</mi> </msub> </mrow> </math> Then it means that there is no shifted training sequence.

When the shifted midamble of the system specifies the allocation mode (UESPECFIC) for the user, the change is that, compared to the default mode, step D is no longer performed, only the corresponding steps a, B, C are performed, i.e. the step of detecting shifted midambles of other users will not be performed any more.

The above-described embodiments of the method for detecting shifted sequences in three allocation manners in TD-SCDMA system are used for exemplary purposes to illustrate the principles and features of the present invention, and are not intended to limit the present invention, so that modifications and equivalents thereof that are within the scope of the present invention will be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims (12)

1.A method for detecting a shift sequence in a time division synchronous code division multiple access system is characterized by comprising the following steps:

A. obtaining the position of corresponding noise according to the position of the effective path, then calculating average noise according to the noise position pair, and generating a noise judgment threshold;

B. detecting discontinuous transmission, and when the system is configured to be in a discontinuous transmission state, detecting the discontinuous transmission state; when the system configuration does not use the discontinuous transmission state, directly executing the step C;

if the system is not in the discontinuous transmission state, executing the step C;

if the system is in the discontinuous transmission state, finishing the subsequent operation of the current channel;

C. and calculating whether other estimation windows except the first estimation window in each physical code combined transmission channel of the target user are effective.

2. The method of detecting shifted sequences according to claim 1, further comprising:

D. and after the detection of the estimation window of the target user is finished, estimating the estimation windows of other users.

3. The method according to claim 1, wherein the step a comprises the following steps:

a1. calculating the average noise power:

determining the position of the noise path according to the path information phi of the effective path position, and calculating to obtain the position information of the noise path

Simultaneously calculating the average value of the noise power at the noise position and the average noise P in the frame based on the obtained channel estimate DP_noise：

<math> <mrow> <msub> <mi>P</mi> <mi>noise</mi> </msub> <mo>=</mo> <mfrac> <mrow> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <mrow> <mo>(</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>w</mi> </munderover> <mrow> <mo>(</mo> <mi>D</mi> <msub> <mi>P</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mtext>&times;</mtext> <msub> <mi>NoiseMask</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>)</mo> </mrow> </mrow> <mrow> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>W</mi> </munderover> <msub> <mi>NoiseMask</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>;</mo> </mrow> </math>

Wherein NoiseMask_t(k) Representing the noise position of the kth sampling point of the t-th shift training sequence obtained by the path information and the position of noise generated by phi;

DP_t(k) representing the channel estimation module value of the kth sampling point of the t-th shift training series;

Φ is the location of the active path;

w represents the length of the channel estimation window considering the channel oversampling multiple speed;

t is a set of shifted training sequences of different windows selected for calculating noise;

a2. calculating detection threshold Thr of discontinuous reception_DTX：

Thr_DTX＝P_nosise*K_DTX；

Wherein, K_DTXIs a preset threshold.

4. The shifted sequence detecting method according to claim 3, wherein when calculating the average value of the noise power at the noise position, the average value is taken for a part of the noise position.

5. The method of claim 3, wherein K is the same as K_DTXThe dynamic change can be obtained through a field test or simulation method or can be self-adapted according to the field condition.

6. The method for detecting a shifted sequence according to claim 1, wherein the detecting the discontinuous transmission state specifically comprises:

computingMaximum value P of channel estimation value DP in the first estimation window of each physical coding combined transmission channel (CCTrCH) at effective path position_max ^First：

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>First</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>first</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

Wherein, first represents the number of the first estimation window of the physical code combined transmission channel.

7. The method for detecting shifted sequences according to claim 6, further comprising the step of first window validity judgment:

judging the maximum value P of the first estimation window of each physical code combined transmission channel of all target users_max ^firstWhether it is not less than the threshold Thr_DTX；

If it is $P_{\max }^{\mathrm{First}}>{\mathrm{Thr}}_{\mathrm{DTX}}$ When the effective receiving signal exists in the channel, executing the step C;

and when the system is in the discontinuous transmission state, closing the subsequent execution operation.

8. The method of shifted sequence detection according to claim 1, wherein the detection of the validity of the other estimation windows of the target user is achieved by:

c1. searching the maximum estimation value of each estimation window in the target user: calculating the maximum value of the channel estimation value DP in the first estimation window of the current physical coding combination transmission channel:

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>First</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>first</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

wherein, first represents the number of the first estimation window of the physical code combined transmission channel;

c2. normalization operation of channel estimation of target user:

$P_{\mathrm{Code}}=P_{\max }^{\mathrm{First}}/\sqrt{N_c};$

wherein N is_cIs a normalization factor; p_CodeIs the normalized maximum value;

c3. calculating P_CodeCorresponding normalized maximum threshold Th _ X_OwnMA：

Th_X_OwnMA＝P_Code*T_{own_max}；

Wherein, T_{Own_max}Is a set threshold;

c4. calculating detection threshold Th of target user residual estimation window_ownI.e. calculating the estimate window other than the first estimate window in the current code combined transmission channelThe final detection threshold of (2);

c5. calculating the maximum value of the residual estimation windows of the target user, namely calculating the maximum value P of the path positions marked by the path information phi of other estimation windows except the first estimation window in the current code combined transmission channel_t：

<math> <mrow> <msub> <mi>P</mi> <mi>t</mi> </msub> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

Wherein, t belongs to OwnCCTrCH, which distributes all possible estimation windows of the channel except the first estimation window for the current coding combined transmission channel of the target user;

c6. and (3) detecting the effectiveness of the residual estimation window of the target user: by comparing the maximum value P of the residual shifted training sequence estimation window in the current code combined transmission channel_tWhether greater than the threshold Th_ownTo determine whether the estimation window of the shifted training sequence is valid:

if P_t≥Th_ownIf yes, the estimation window of the t-th shift training sequence is considered to be effective;

c7. target user activation estimation window correction: if a certain estimation window of a coded combined transmission channel with a large sequence number is detected to be effective, the estimation window with the sequence number smaller than the number of the estimation window is considered to be effective;

c8. combining the normalized channel estimates of all activated shifted training sequence estimation windows through a certain coded composite transmission channel, and calculating the normalized channel estimate of a certain shifted training sequence of the certain coded composite transmission channel:

<math> <mrow> <msub> <mi>codeDP</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mi>t</mi> <mi>T</mi> </munderover> <mfrac> <mrow> <msub> <mi>DP</mi> <mi>t</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <msqrt> <msub> <mi>N</mi> <mi>t</mi> </msub> </msqrt> </mfrac> <mo>;</mo> </mrow> </math>

wherein, CodedP_i(k)_tNormalizing the channel estimation value for the k point of the shift training series of the ith coding combination transmission channel;

N_tnormalized channelization code number for the t-th shifted training series;

t is a shift training sequence set of the ith code combined transmission channel of the target user;

c9. target user channel estimation normalization: when the target user occupies multiple coded combined transmission channels, the normalized channel estimates CodeDP of the target user for all coded combined transmission channels are averaged, and the normalized combined channel estimate of the final activated channel estimate is calculated:

<math> <mrow> <msub> <mi>codeDP</mi> <mi>own</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mi>l</mi> </mrow> <msub> <mi>N</mi> <mrow> <mi>CCTrCH</mi> <mo>_</mo> <mi>Num</mi> </mrow> </msub> </munderover> <msub> <mi>codeDP</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <msub> <mi>N</mi> <mrow> <mi>CCTrCH</mi> <mo>_</mo> <mi>Num</mi> </mrow> </msub> </mfrac> <mo>.</mo> </mrow> </math>

9. the method of claim 8Method for bit sequence detection, characterized in that said normalization factor N_cThe number of the activated channelisation codes corresponding to each shift training sequence is counted in the normalization factor according to the channelisation codes which are specified by the protocol and are allocated to the target user.

10. The method of claim 8, wherein the detection threshold Th of the target user residual estimation window is set to_ownFor normalized maximum threshold Th _ X_OwnMAOr discontinuous reception threshold Thr_DTX。

11. The method of shifted sequence detection according to claim 2, wherein said estimating the estimation windows of other users is performed by:

detecting whether the number of estimation windows supported by the current system is completely distributed to a target user, if so, ending; otherwise, the following steps are continuously executed:

a normalized maximum value for the target user is calculated,

<math> <mrow> <msubsup> <mi>P</mi> <mi>max</mi> <mi>Own</mi> </msubsup> <mo>=</mo> <munder> <mi>max</mi> <mrow> <mi>k</mi> <mo>&Element;</mo> <mi>&Phi;</mi> </mrow> </munder> <mrow> <mo>(</mo> <msub> <mi>codeDP</mi> <mi>own</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

calculating the maximum threshold of each estimation window of other users:

$X_{\mathrm{MA}}=P_{\max }^{\mathrm{Own}}*T_{\max };$

wherein, T_maxA preset threshold for detecting the maximum value of the estimation window of other users;

determining the shift sequence detection threshold of other users and setting the threshold at the normalized maximum value Th _ X_MAAnd threshold for discontinuous reception^ThrDTXThe larger one of them, or any one of them, namely:

Th＝max(Th_X_MA，Thr_DTX)；

or Th _ X_MA；

Or Th ═ Thr_DTX；

Calculating maximum value of estimation window of shifted training sequence of other users

$P_t=\underset{k=\{l:W\}}{\max }\left({\mathrm{DP}}_t\left(k\right)\right);$

Wherein,

wherein, t _ OwnCCTrCH, said OwnCCTrCH is all possible estimation windows of the channel of the estimation window except all coded combined transmission channel allocation of the target user;

for other users: if P_t≥Th_ownThen the estimation window of the shifted training sequence is valid.

12. The method of claim 11, wherein the threshold Th for detecting the shifted sequences of other users is a normalized maximum threshold Th _ X_MAOr threshold of discontinuous receptionThr_DTX。

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