CN1885745A - Synchronization realizing method under strong interference in mobile communication system - Google Patents

Abstract

The related synchronous method in TDM-CDMA communication system comprises: (1) taking multiple correlation calculation to received two frame signal and local down candidate code in ROM; (2) taking modulus and squaring former result; (3) calculating the local peak-average rate; (4) finding out the maximal value to determine down synchronous code number and pilot frequency time slot position. Compared to prior art, this invention needs not much added cost fit implementation by FPGA.

Description

Synchronous implementation method in the mobile communication system under the strong jamming

[technical field]

The present invention relates to moving communicating field, relate in particular to the synchronous implementation method under the strong jamming in a kind of TDS-CDMA mobile communication system that when cell initial search and sub-district gravity treatment, adopts.

[technical background]

The terminal equipment of the mobile communication system of time division duplex or trunking all must carry out down-going synchronous powering on when carrying out cell initial search or sub-district gravity treatment.

As shown in Figure 1, for the TD-SCDMA mobile communication system, the subframe of each 5ms is by 3 special time slots and 7 conventional time slot (TS0～TS6) form.Conventional time slot is as transmitting user data or control information.In these 7 conventional time slots, TS0 always comes the transmitting system broadcast message as descending time slot regularly, and TS1 is always regularly as ascending time slot.Other conventional time slot can be configured to upstream or downstream as required neatly, to realize the transmission of asymmetric traffic.3 special time slots comprise descending pilot frequency time slot (DwPTS:Downlink Pilot Time Slot), uplink pilot time slot (UpPTS:Uplink Pilot Time Slot) and protection (GP:Guard Period) at interval.

A critical process of down-going synchronous is to determine descending synchronous code SYNC-DL (SynchronizationCode-Downlink).The employed descending synchronous code of TD-SCDMA system according to the 3GPP regulation has good auto-correlation and their cross correlation, so searching downlink synchronous code generally uses matched filter (correlator) to realize.Specifically, just receive the position of data and the peak-peak of the correlation of SYNC-DL sign indicating number, thereby the position of definite DwPTS time slot is carried out synchronously by search one frame.Existing algorithm is more or less the same in each time slot transmitting power, when perhaps DwPTS time slot transmitting power is greater than other time slot, is very effective.But when the transmitting power of other time slot during considerably beyond the transmitting power of DwPTS time slot, the DwPTS time slot receives data and will be far smaller than other time slot and send SYNC-DL sign indicating number correlation with the peak value that sends SYNC-DL sign indicating number correlation, gap reaches several magnitude, this moment, existing synchronized algorithm lost efficacy, and made mistakes synchronously.It should be noted that it is to have the situation of the transmitting power of other time slot really in practice considerably beyond the transmitting power of DwPTS time slot.For example, far away when the terminal or the trunking that carry out cell initial search or sub-district gravity treatment from the base station, and exist when carrying out the terminal equipment of up access near it, the power of the descending pilot frequency time slot that receives will be far smaller than the power of ascending time slot.

[summary of the invention]

Purpose of the present invention will overcome above-mentioned deficiency exactly, synchronous implementation method under the strong jamming in a kind of TDS-CDMA mobile communication system is provided, terminal or trunking are far longer than under the situation of descending pilot frequency time slot transmitting power in other time slot transmitting power, still can effectively carry out synchronously, and the demand that assesses the cost that increases is less, is beneficial to programmable gate array (FPGA) and realizes.

The objective of the invention is to be achieved through the following technical solutions:

Synchronous implementation method in this mobile communication system under the strong jamming comprises the steps:

(1) the two continuous frames signal that receives and the descending synchronous code Candidate key in the local read-only memory are carried out the multiple correlation computing, obtain the result of multiple correlation computing;

(2) to the delivery as a result of above-mentioned related operation square;

(3) a delivery square gained result being carried out local peak-to-average force ratio calculates;

(4) search for maximum in the local peak-to-average force ratio with comparator, determine the position of the sign indicating number number and the descending pilot frequency time slot of descending synchronous code with this value.

Compared with prior art, the present invention possesses following advantage: even terminal or trunking are far longer than under the situation of descending pilot frequency time slot transmitting power in other time slot transmitting power, the present invention still can carry out synchronously effectively, and the demand that assesses the cost that increases is less, is beneficial to programmable gate array and realizes.

[description of drawings]

Fig. 1 is a TD-SCDMA subframe structure schematic diagram;

Fig. 2 is a realization flow schematic diagram of the present invention.

[embodiment]

The present invention is further illustrated below in conjunction with drawings and Examples:

See also Fig. 2, the synchronous implementation method in the mobile communication system of the present invention under the strong jamming comprises the steps:

(1) terminal or trunking begin searching downlink synchronous code number, preserve the reception data e of two continuous frames, set the descending synchronous code i=0 of initial calculation, the signal of described two continuous frames data and the descending synchronous code Candidate key in the local read-only memory are carried out the multiple correlation computing, obtain the c as a result of multiple correlation computing, the multiple correlation computing realizes with multiplier and adder;

(2) to the delivery of c as a result of above-mentioned related operation square, the delivery square operation is realized with multiplier and adder;

(3) adopt division or ask the mode of logarithm that a delivery square gained result is carried out local peak-to-average force ratio pr and calculate;

(4) search for local peak-to-average force ratio pr with comparator ⁽ⁱ⁾, i=0,1, the maximum among the L 31 is determined the position of the sign indicating number number and the descending pilot frequency time slot of descending synchronous code with this value.

According to above-mentioned steps, the present invention further can realize with reference to following formula and process:

Suppose that two frames receive data and are: e={e ₀, e ₂, L e ₁₂₇₉₉;

The Candidate key of descending synchronous code is: $s^{\left(i\right)}=\left\{\begin{array}{cc}{s}_0^{\left(i\right)},s_2^{\left(i\right)},L& s_{63}^{\left(i\right)}\end{array}\right\},i=\begin{array}{cc}\mathrm{0,1},L& 31\end{array}$ The expression Candidate key the sign indicating number number;

Then:

Step is carried out the multiple correlation computing by following formula in (1):

$c^{\left(i\right)}=\left\{\begin{array}{cc}{c}_0^{\left(i\right)},c_2^{\left(i\right)},L& c_{12736}^{\left(i\right)}\end{array}\right\},i=\begin{array}{cc}\mathrm{0,1},L& 31,\end{array}$

Wherein: $c_k^{\left(i\right)}=\underset{j=0}{\overset{63}{\mathrm{\Σ}}}{s}_j^{{\left(i\right)}^{*}}{\·e}_{k+j};$

Press following formula delivery in the step (2):

$d^{\left(i\right)}=\left\{\begin{array}{cc}{d}_0^{\left(i\right)},d_2^{\left(i\right)},L& d_{12736}^{\left(i\right)}\end{array}\right\}=\left\{\begin{array}{cc}{\left|\right|c_0^{\left(i\right)}\left|\right|}^2,{\left|\right|c_2^{\left(i\right)}\left|\right|}^2,L& {\left|\right|c_{12736}^{\left(i\right)}\left|\right|}^2\end{array}\right\},i=\begin{array}{cc}\mathrm{0,1},L& 31;\end{array}$

Step is carried out the calculating of local peak-to-average force ratio by following formula in (3):

${\mathrm{pr}}^{\left(i\right)}=\left\{\begin{array}{cc}{\mathrm{pr}}_0^{\left(i\right)},{\mathrm{pr}}_2^{\left(i\right)},L& {\mathrm{pr}}_{12736-x-y}^{\left(i\right)}\end{array}\right\},i=\begin{array}{cc}\mathrm{0,1},L& 31,\end{array}$

That is,

${\mathrm{pr}}_m^{\left(i\right)}=\frac{d_{m+x}^{\left(i\right)}}{\left(\underset{n=m,n\≠m+x}{\overset{m+x+y}{\mathrm{\Σ}}}{d}_n^{\left(i\right)}\right)}m=\mathrm{0,1,12736}-x-y,i=\begin{array}{cc}\mathrm{0,1},L& 31,\end{array}$

Form the feature of power window according to DwPTS time slot and front and back GP, with reference to shown in Figure 1; Ask the maximum of local peak-to-average force ratio in the step (4) by following formula:

${\mathrm{pr}}_M^I=\mathrm{MAX}\left({\mathrm{pr}}_m^{\left(i\right)}\right),m=\mathrm{0,1,12736}-x-y---i=\begin{array}{cc}\mathrm{0,1},L& 31,\end{array}$

Wherein I is the descending synchronous code number of current area, the number of samples that on behalf of descending pilot frequency time slot DwPTS, M depart from receiving two continuous frames data e.

In above-mentioned formula and process processing, step (3) adopts division arithmetic to ask local peak-to-average force ratio, and division arithmetic need expend a large amount of FPGA resources, is unfavorable for the realization of FPGA, therefore in order to reduce computation requirement, in step (3), also can use following formula and find the solution local peak-to-average force ratio:

${\mathrm{pr}}_m^{\left(i\right)}=10*\lg \left(\frac{d_{m+x}^{\left(i\right)}}{\left(\underset{n=m,n\≠m+x}{\overset{m+x+y}{\mathrm{\Σ}}}{d}_n^{\left(i\right)}\right)}\right)=10*\lg \left(d_{m+x}^{\left(i\right)}\right)-10*\lg \left(\underset{n=m,n\≠m+x}{\overset{m+x+y}{\mathrm{\Σ}}}{d}_n^{\left(i\right)}\right)m=\mathrm{0,1,12736}-x-y,i=\left[\begin{array}{cc}\mathrm{0,1},L& 31\end{array}\right]$

Utilize the operation of logarithm to realize with the look-up table of certain bit width easily, can reduce required FPGA capacity significantly like this, reduce the expense of FPGA door.

This shows that the present invention greatly reduces computation requirement, be suitable for realizing, can bring into play superior synchronizing function with FPGA.

Claims (6)

1, the synchronous implementation method under the strong jamming in a kind of mobile communication system is characterized in that comprising the steps:

(1) the two continuous frames signal that receives and the descending synchronous code Candidate key in the local read-only memory are carried out the multiple correlation computing, obtain the result of multiple correlation computing;

(2) to the delivery as a result of above-mentioned related operation square;

(3) a delivery square gained result being carried out local peak-to-average force ratio calculates;

(4) search for maximum in the local peak-to-average force ratio with comparator, determine the position of the sign indicating number number and the descending pilot frequency time slot of descending synchronous code with this value.

2, the synchronous implementation method under the strong jamming in the mobile communication system according to claim 1 is characterized in that handling according to following formula and process:

Suppose that two frame signals are: e={e ₀, e ₂, L e ₁₂₇₉₉;

Candidate key is: $s^{\left(i\right)}=\{s_0^{\left(i\right)},s_2^{\left(i\right)},L,s_{63}^{\left(i\right)}\},i=\mathrm{0,1},L,31$ The expression Candidate key the sign indicating number number;

Then:

Step is carried out the multiple correlation computing by following formula in (1):

$c^{\left(i\right)}=\{c_0^{\left(i\right)},c_2^{\left(i\right)},L,c_{12736}^{\left(i\right)}\},i=\mathrm{0,1},L,31,$

Wherein: $c_k^{\left(i\right)}=\underset{j=0}{\overset{63}{\mathrm{\Σ}}}{s}_j^{{\left(i\right)}^{*}}\·e_{k+j};$

Press following formula delivery in the step (2):

$d^{\left(i\right)}=\{d_0^{\left(i\right)},d_2^{\left(i\right)},L,d_{12736}^{\left(i\right)}\}=\{{\left|\right|c_0^{\left(i\right)}\left|\right|}^2,{\left|\right|c_2^{\left(i\right)}\left|\right|}^2,L,{\left|\right|c_{12736}^{\left(i\right)}\left|\right|}^2\},i=\mathrm{0,1},L,31;$

Step is carried out the calculating of local peak-to-average force ratio by following formula in (3):

${\mathrm{pr}}^{\left(i\right)}=\{{\mathrm{pr}}_0^{\left(i\right)},{\mathrm{pr}}_2^{\left(i\right)},L,{\mathrm{pr}}_{12736-x-y}^{\left(i\right)}\},i=\mathrm{0,1},L,31,$

That is,

${\mathrm{pr}}_m^{\left(i\right)}=\left(\frac{d_{m+x}^{\left(i\right)}}{\left(\underset{n=m,n\≠m+x}{\overset{m+x+y}{\mathrm{\Σ}}}{d}_n^{\left(i\right)}\right)}\right)m=\mathrm{0,1,12736}-x-y,i=\mathrm{0,1},L,31$

Ask the maximum of local peak-to-average force ratio in the step (4) by following formula:

${\mathrm{pr}}_M^I=\mathrm{MAX}\left({\mathrm{pr}}_m^{\left(i\right)}\right),m=\mathrm{0,1,12736}-x-y,i=\mathrm{0,1},L,31,$

Wherein I is the descending synchronous code number of current area, the number of samples that on behalf of descending pilot frequency time slot DwPTS, M depart from receiving two continuous frames data e.

3, the synchronous implementation method under the strong jamming in the mobile communication system according to claim 1 is characterized in that handling according to following formula and process:

Suppose that two frame signals are: e={e ₀, e ₂, L e ₁₂₇₉₉;

Candidate key is: $s^{\left(i\right)}=\{s_0^{\left(i\right)},s_2^{\left(i\right)},L,s_{63}^{\left(i\right)}\},i=\mathrm{0,1},L,31;$

Then:

Step is carried out the multiple correlation computing by following formula in (1):

$c^{\left(i\right)}=\{c_0^{\left(i\right)},c_2^{\left(i\right)},L,c_{12736}^{\left(i\right)}\},i=\mathrm{0,1},L,31,$

Wherein: $c_k^{\left(i\right)}=\underset{j=0}{\overset{63}{\mathrm{\Σ}}}{s}_j^{{\left(i\right)}^{*}}\·e_{k+j};$

Press following formula delivery in the step (2):

$d^{\left(i\right)}=\{d_0^{\left(i\right)},d_2^{\left(i\right)},L,d_{12736}^{\left(i\right)}\}=\{{\left|\right|c_0^{\left(i\right)}\left|\right|}^2,{\left|\right|c_2^{\left(i\right)}\left|\right|}^2,L,{\left|\right|c_{12736}^{\left(i\right)}\left|\right|}^2\},i=\mathrm{0,1},L,31;$

Step is carried out the calculating of local peak-to-average force ratio by following formula in (3):

${\mathrm{pr}}_m^{\left(i\right)}=10*\lg \left(\frac{d_{m+x}^{\left(i\right)}}{\left(\underset{n=m,n\≠m+x}{\overset{m+x+y}{\mathrm{\Σ}}}{d}_n^{\left(i\right)}\right)}\right)=10*1g\left(d_{m+x}^{\left(i\right)}\right)-10*1g\left(\underset{n=m,n\≠m+x}{\overset{m+x+y}{\mathrm{\Σ}}}{d}_n^{\left(i\right)}\right)m=\mathrm{0,1,12736}-x-y,i=\mathrm{0,1},L,31$

Ask the maximum of local peak-to-average force ratio in the step (4) by following formula:

${\mathrm{pr}}_M^I=\mathrm{MAX}\left({\mathrm{pr}}_m^{\left(i\right)}\right),m=\mathrm{0,1,12736}-x-y,i=\mathrm{0,1},L,31,$

Wherein I is the descending synchronous code number of current area, the number of samples that on behalf of descending pilot frequency time slot DwPTS, M depart from receiving two continuous frames data e.

4,, it is characterized in that the multiple correlation computing in the step (1) realizes with multiplier and adder according to the synchronous implementation method under the strong jamming in any described mobile communication system in the claim 1 to 3.

5,, it is characterized in that the delivery square operation in the step (2) is realized with multiplier and adder according to the synchronous implementation method under the strong jamming in any described mobile communication system in the claim 1 to 3.

6, the synchronous implementation method under the strong jamming in the mobile communication system according to claim 3 is characterized in that division in the step (3) asks the ratio utilization realization of tabling look-up of taking the logarithm.

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