CN1815934A - Code resource distribution method of reducing CDMA mobile telecommunication system interference - Google Patents

Abstract

In CDMA cellular system, using scrambled code and channelized code to determine user's spread spectrum code. The scrambled code is in use for sorting sub zones, and the channelized code is in use for sorting users in a sub zone. The invention is suitable to TD-CDMA system with smaller gain of spread spectrum, and frequency division duplex CDMA system with higher communication speed. According to current scheme of TD-SCDMA system, spread spectrum codes distributed for users between sub zones could possess large correlativity so as to generate severe interference. Based on cross correlation of all spread spectrum codes, the method divides scrambled codes into different sets. Scrambled codes with good performance of cross correlation are assigned to adjacent sub zones. Channelized codes are assigned to users located at margin of adjacent sub zones to make spread spectrum codes possess better cross correlation. Advantages are: restraining interference, and raising system capacity.

Description

A kind of code-resource distribution method that reduces the code vision multiple address cellular mobile communication system interference

Technical field

The invention belongs to the communications field, relate in particular to the code-resource distribution method that a kind of novel reduction code division multiple access (CDMA) cell mobile communication systems disturbs.

Background technology

The cdma cellular mobile communication system utilizes different spreading codes to distinguish different user, obtains high capacity.Generally in the cdma cellular mobile communication system, determine a user's spreading code with scrambler and channel code, scrambler is mainly used in distinguishing cell, and channel code is used to distinguish a user in the sub-district.If the sign indicating number resource that the user of neighbor cell distributes does not have good quadrature performance (promptly having stronger cross correlation), the user who is in cell edge may be subjected to serious presence of intercell interference, systematic function is descended greatly, and promptly systematic function has very big relation with the spreading code of selecting for use.With the TD-SCDMA system is that example describes: wherein to be whole 128 scramblers that will adopt be divided into 32 groups according to the sequence number of sign indicating number to scrambling code distribution method in turn, is the scrambler on the same group of neighbor cell allocation; For user's assigns channelization codes is not considered the influence [" Technical Specification Group Radio Access Network:Spreading andmodulation (TDD) " to the cross-correlation performance of customer location and spreading code, TS25.223, V5.3.0,3GPP].The right cross-correlation performance of spreading code under all scramblers is being analyzed the back discovery, this scrambler and channelization code allocation method are not considered the influence of the branch pairing minizone spreading code of scrambler and channel code to the cross-correlation performance, may distribute the very strong spreading code of cross correlation for the edge customer of neighbor cell, systematic function is had a strong impact on.

Summary of the invention

The objective of the invention is in appropriate distribution code division multiple access (CDMA) cell mobile communication systems in order to the scrambler of distinguishing cell with in order to distinguish user's channel code, effectively reduce the neighbor cell user and use cross correlation between the spreading code, reduce presence of intercell interference, thereby reach the purpose of improving communication quality, improving power system capacity and enhanced system stability.The present invention is applicable to time division duplex (TDD) cdma system and Frequency Division Duplexing (FDD) (FDD) cdma system simultaneously, Frequency Division Duplexing (FDD) (FDD) cdma system when being particularly useful for time division duplex (TDD) cdma system and user's communications speed higher (spreading gain is less).

The present invention is mainly by the cross-correlation performance between whole spreading codes (scrambler+channel code) of analyzing the employing of code division multiple access (CDMA) cell mobile communication systems, and according to its characteristic, scrambler is divided into different scrambler collection, scrambler a little less than the cross correlation is distributed to adjacent sub-district, and the strong scrambler of cross correlation can be distributed in sub-district far away; Distributing according to such scheme on the basis of cell scrambling, for this sub-district zones of different (optional) is divided different channel code Wai Ji and Nei Ji, for consider that the interference size degree that it causes neighbor cell, the channel code its position/angle of dynamic assignment/zone under collect in the sub-district during user's assigns channelization codes outward or interior collection in channel code.Concrete steps are as follows:

1, the spreading code (scrambler+channel code) that the cdma cellular mobile communication system is adopted carries out the right cross-correlation performance analysis of spreading code between any two.Attention: only to the spreading code under the different scrambling codes to carrying out the analysis of cross-correlation performance, and not to the spreading code under the same scrambler to carrying out the analysis of cross-correlation performance; Spreading code is drawn together cross-correlation performance analysis when synchronous and asynchronous to cross-correlation performance analysis package.Establish appropriate judgment criterion, to the cross-correlation performance that spreading code is right classify (good, bad, unacceptable).

Calculate a spreading code to (C _iAnd C _jTwo spreading codes) formula of synchronous cross correlation is as shown in the formula (1).

${\mathrm{\ρ}}_{\mathrm{ij}}^0=\frac{1}{N}*|\underset{k=1}{\overset{N}{\mathrm{\Σ}}}{C}_i\left(k\right)*C_j\left(k\right)|---\left(1\right)$

Calculate a spreading code to (C _iAnd C _jTwo spreading codes) formula of asynchronous cross correlation is as shown in the formula (2).

${\mathrm{\&rho;}}_{\mathrm{ij}}^{\mathrm{\&tau;}}=\left\{\begin{array}{c}\frac{1}{N}*\left[\mathrm{\&alpha;}\right|\underset{k=1+\mathrm{\&tau;}}{\overset{N}{\mathrm{\&Sigma;}}}{C}_i\left(k\right)*C_j(k-\mathrm{\&tau;})|+\mathrm{\&beta;}|\underset{k=1}{\overset{\mathrm{\&tau;}}{\mathrm{\&Sigma;}}}{C}_i\left(k\right)*C_j(k-\mathrm{\&tau;})|],0<\mathrm{\&tau;}<N\\ \frac{1}{N}*\left[\mathrm{\&alpha;}\right|\underset{k=1}{\overset{N-\left|\mathrm{\&tau;}\right|}{\mathrm{\&Sigma;}}}{C}_i\left(k\right)*C_j(k+|\mathrm{\&tau;}\left|\right)|+\mathrm{\&beta;}|\underset{k=N-\left|\mathrm{\&tau;}\right|+1}{\overset{N}{\mathrm{\&Sigma;}}}{C}_i\left(k\right)*C_j(k-N+|\mathrm{\&tau;}\left|\right)\left|\right],-N<\mathrm{\&tau;}<0\end{array}-\left(2\right)\right.$

Variable, parameter in formula (1) and the formula (2) are explained as follows: N is a spreading code length; τ is a spread spectrum codes C _jWith respect to spread spectrum codes C _iTime delay (integer); Parameter alpha, β is a weight coefficient.Need to prove, as | τ | during 〉=N, the right cross-correlation function of spreading code is | τ | and the periodic extension of cross-correlation function during＜N.

More than provided the calculating formula of a pair of spreading code to cross-correlation function.Provide below and weigh the calculating formula of a pair of spreading code, as shown in the formula (3) the cross-correlation performance.

${\mathrm{\&rho;}}_{\mathrm{ij}}=\frac{\underset{k=-N+1}{\overset{N-1}{\mathrm{\&Sigma;}}}{r}_k{\mathrm{\&rho;}}_{\mathrm{ij}}^k}{\underset{k=-N+1}{\overset{N-1}{\mathrm{\&Sigma;}}}{r}_k}---\left(3\right)$

Wherein, r _k＞0, k=0, ± 1, ± 2 ..., ± (N-1) be the weight coefficient of the cross-correlation function during to time delay τ=k.

Afterwards, the judgment criterion that spreading code is classified to the cross-correlation performance can be at above-mentioned resulting cross-correlation performance metric ρ _IjThe basis on carry out.Can set up two threshold value ρ ₁, ρ ₂, and 0＜ρ ₁＜ρ ₂≤ 1, and adjudicate by following criterion:

A. if 0≤ρ _Ij＜ρ ₁, then think C _iAnd C _jCross-correlation performance good (weak);

B. if ρ ₁≤ ρ _Ij＜ρ ₂, then think C _iAnd C _jCross-correlation performance poor (by force);

C. if ρ ₂≤ ρ _Ij≤ 1, then think C _iAnd C _jCross-correlation performance unacceptable (extremely strong);

2, divide the method for scrambler collection.The analysis showed that, some scrambler has similar their cross correlation, this is meant, the cross-correlation performance the same or similar substantially (spreading code of different classes of cross-correlation performance is the same or equal substantially to quantity) between the spreading code that any one scrambler of spreading code and other that these scramblers produce produces.Based on this specific character, all scrambler SC can be divided into several scrambler collection, all scramblers in the same scrambler collection all have the same or similar cross-correlation performance.The analysis of cross-correlation performance also shows, all exists the unacceptable spreading code of cross-correlation performance right between any two scramblers in the same scrambler collection, and does not all exist the unacceptable spreading code of cross-correlation performance right between any two scramblers in the different scrambling codes collection.

Whole M the scrambler SC that the system of being about to can use ₀, SC ₂..., SC _M-1Be divided into L (the individual scrambler collection SCS of L＜M) ₁, SCS ₂..., SCS _L, these scrambler collection comprise several scramblers that quantity equates or do not wait, and satisfy following formula (4) and (5).

SCS _i∩SCS _j＝Φ，i≠j (4)

$\underset{i=1}{\overset{L}{\&cup;}}\mathrm{SC}{S}_i=\mathrm{\&Omega;}---\left(5\right)$

3, the scrambling code distribution method the during network planning.According to the top scrambler collection of dividing, the primitive rule that scrambler distributes when the network planning is that neighbor cell can not distribute the different scrambling codes in the same scrambler collection, if promptly certain cell allocation a scrambler in certain scrambler collection, other scrambler in the same scrambler collection all can not be distributed in the sub-district that then is adjacent.The scrambler distribution ratio of non-adjacent sub-district is more flexible, can distribute the scrambler in the different scrambling codes collection, also can distribute the different scrambling codes in the same scrambler collection.

In concrete enforcement, can introduce a new argument: the multiplexing factor Q of scrambler collection, assist and carry out the distribution of cell scrambling.Microzonation in the network is divided into several cell clusters, comprises Q sub-district in the cell cluster; To Q sub-district in the cell cluster, to the scrambler in Q different scrambling codes collection of they distribution; The scrambler of Q sub-district in the neighbor cell bunch in can multiplexing this Q scrambler collection, but need select original scrambler in this Q the scrambler collection for use; When in certain scrambler collection, not having original scrambler, the wherein used scrambler of reusable just now.More flexible when determining the multiplexing factor Q of scrambler collection, can make it big as far as possible, also can adopt less value, for a part of scrambler resource is reserved in the follow-up network capacity extension.

4, divide the method for the channelization code set of a sub-district.Determine the scrambler of certain sub-district and its neighbor cell by such scheme after, at first the All Ranges that this sub-district covers is divided into several interference regions according to signal arrival angle (DOA) or shape beam angle (optional), the division principle of interference region is that the signal of the user in the zones of different can cause serious interference to different neighbor cells, i.e. the property distinguished of serious interfered cell; Then at each interference region,, the channel code of current area is divided into different channelization code set according to the right cross-correlation performance of all spreading codes of serious interfered cell in this sub-district and this zone.Reach under angle (DOA) or the shape beam angle (optional) at certain signal, be called outer collection under this interference region, the stronger interior collection that is called under this interference region with the set of more weak this cell channelization sign indicating number of neighbor cell spreading code cross correlation.

In this step, can be divided into two kinds of situations:

A. technology such as adaptive antenna or smart antenna are not adopted in the sub-district, and system can't know that user's signal arrives angle (DOA) information.Then the division of the channelization code set of this sub-district does not need to consider that signal arrives angle (DOA) factor, and promptly the sub-district has only an interference region (all overlay areas), and its serious sub-district of disturbing is its all neighbor cells.The cross-correlation performance right according to all spreading codes of this sub-district and its all neighbor cells formation (referring to step 1), is divided into all channel codes of this sub-district the subclass of two non-overlapping copies: outer collection (this cell channelization sign indicating number set more weak with neighbor cell spreading code cross correlation) and interior collection (this cell channelization sign indicating number set stronger with neighbor cell spreading code cross correlation).

B. technology such as adaptive antenna or smart antenna have been adopted in the sub-district, and system can know that user's signal arrives angle (DOA) information.Then at first according to this reality of interference that can cause different neighbor cells under the different angles position in various degree, with the whole area dividing that the sub-district covered is several interference regions, and determines that the signal of user in each interference region can cause the most several neighbor cells (suggestion is chosen 1～3) of serious interference.Then at each interference region, the right cross-correlation performance of spreading code of disturbing all spreading codes of the most serious several sub-districts to form according to subscriber signal in the spreading code of this sub-district and this zone (referring to step 1), is divided into all channel codes of this sub-district the subclass of two non-overlapping copies: Wai Ji and Nei Ji.Attention: user's signal can cause serious interference to different neighbor cells in the different interference regions, when therefore disturbing the area dividing channelization code set at difference, cross-correlation performance between the spreading code of needs consideration and different districts, so the channel code Wai Ji of different interference area dividing is different with Nei Ji, but they can have identical part.

5, be the method for user's assigns channelization codes of a sub-district.Need consider the user for the method for user's assigns channelization codes and neighbor cell be caused the big or small degree of interference.Determine the annoyance level of user's signal in view of the above: seriously still slight to neighbor cell interference to neighbor cell interference to neighbor cell.Answer the channel code under its place interference region of priority allocation to collect outward to the serious user of neighbor cell interference, but and to collecting in the channel code under slight its place interference region of user's priority allocation of neighbor cell interference.

The signal of determining the user can carry out dividing region according to different measured values during to the annoyance level of neighbor cell:

A. the different zonings of pilot signal strength of the home cell that receives when the diverse location according to the user;

B. the different zonings of pilot signal strength of the neighbor cell that receives when the diverse location according to the user;

C. the different zonings of the pilot signal strength difference of home cell that receives when the diverse location according to the user and neighbor cell.This method is adopted in suggestion.

Can set threshold value, determine the annoyance level of user's signal neighbor cell according to the magnitude relationship of measured value and threshold value.Determining and can setting for all sub-districts are unified of threshold value also can be according to configuring condition (antenna, the radius coverage area etc.) difference of this sub-district and its neighbor cell, for different sub-districts is provided with different threshold values.

It should be noted that: if use two kinds of measured values of above-mentioned B, C to determine the annoyance level of sub-district, then can utilize this information and subscriber signal to arrive angle (optional) information, the division of interference region is adjusted neighbor cell.

When determining that the user is in which interference region of this sub-district, can take diverse ways according to following two kinds of different situations:

A. technology such as adaptive antenna or smart antenna are not adopted in the sub-district, and system can't know that user's signal arrives angle (DOA) information.Then this sub-district has only an interference region, can determine that the user must be in this interference region.

B. technology such as adaptive antenna or smart antenna have been adopted in the sub-district, and system can know that user's signal arrives angle (DOA) information.Angle information in the time of then can arriving angle (DOA) and interference region division according to user's signal determines which interference region the user is in.

Then, can be user's assigns channelization codes:, then answer the channel code under its place interference region of priority allocation to collect outward if the user is serious to neighbor cell interference; If the user is slight to neighbor cell interference, but collection in the channel code under its place interference region of priority allocation.

6, the dynamic allocation method of subscriber channel sign indicating number.The user position is not changeless, therefore distributes to user's channel code and should dynamically adjust according to customer location with to the neighbor cell interference degree.When the user when the slight zone of neighbor cell interference being moved to serious regional of neighbor cell interference, the channel code that is distributed need be adjusted into the channel code in the outer collection of channel code under its residing new interference region; Vice versa.When the user moves to another interference region by certain interference region, for the channel code of its distribution also should be adjusted into the outer collection of channel code of its residing new interference region or the channel code in the interior collection.

Should be noted that, when the user moves to another zone by a zone of sub-district, consider the uncertainty of its moving direction, can when redistributing channel code, introduce a time-delay Δ τ or a measurement (referring to the described measured value of top step 5) lagged value Δ σ, when be sure oing that moving of user can be caused change to the neighbor cell interference degree really, redistribute channel code for it again.

Because adopt technique scheme, the present invention has the following advantages and effect:

Method of the present invention is based on the careful analysis to code division multiple access (CDMA) cell mobile communication systems spreading code cross-correlation performance, all scramblers that system is adopted are divided into different scrambler collection according to cross-correlation performance between spreading code, the scrambler that the neighbor cell allocation spreading code is good to the cross-correlation performance; Further, according to the user in the zones of different in the sub-district different neighbor cells are caused this reality of serious interference, cell coverage area is divided into several interference regions, and according to the channel code Wai Ji and the Nei Ji of different each interference region of division of cross-correlation performance of the spreading code of serious interfered cell; Be its assigns channelization codes according to the user to neighbor cell interference degree and two kinds of information of place interference region then.More than a series of technical measures can make between the spreading code of user in spreading code that the user that is in cell edge is assigned to and its serious neighbor cell that disturbs and have good cross-correlation performance, thereby suppress presence of intercell interference greatly, improve communication quality, improve power system capacity.Specific performance is improved situation can be referring to explanation last in Figure 10 and the specific implementation method

Description of drawings

Cell scrambling allocative decision example during Fig. 1 Q=3

Cell scrambling allocative decision example during Fig. 2 Q=7

Fig. 3 Q1=7, cell scrambling allocation example in the network of two-layer cell structure during Q2=4

Fig. 4 does not dispose the middle interfered cell in sub-district (omnidirectional antenna) of smart antenna and divides example

Fig. 5 does not dispose the middle interfered cell in sub-district (directive antenna) of smart antenna and divides example

Fig. 6 disposes the middle interfered cell in sub-district (omnidirectional antenna) of smart antenna and divides example 1

Fig. 7 disposes the middle interfered cell in sub-district (omnidirectional antenna) of smart antenna and divides example 2

Fig. 8 disposes the middle interfered cell in sub-district (directive antenna) of smart antenna and divides example

Fig. 9 disposes the middle channelization code allocation example in sub-district (omnidirectional antenna) of smart antenna

Figure 10 scrambler of the present invention and frequency spreading allocation method effect schematic diagram

Embodiment

Code division multiple access (CDMA) cell mobile communication systems can be divided into FDD-CDMA system and TDD-CDMA system according to the different of duplex mode (FDD and TDD).In the 3G (Third Generation) Moblie standard, that adopt the FDD mode is WCDMA and cdma2000, and that adopt the TDD mode is TD-SCDMA.The present invention can use with all above-mentioned code division multiple accesss (CDMA) cell mobile communication systems in, Frequency Division Duplexing (FDD) (FDD) cdma system when being particularly useful for time division duplex (TDD) cdma system and user's communications speed higher (spreading gain is less).Below carry out case introduction at the TD-SCDMA system.

In the TD-SCDMA system, spreading factor is 16, spreading code length N=16, available scrambling code sum M=128 in the system, each sub-district can with number of channelization codes be 16 (spreading factor is 16 o'clock).

Concrete treatment step is as follows:

1, the spreading code (scrambler+channel code) that the TD-SCDMA system is adopted carries out the right cross-correlation performance analysis of spreading code between any two.Specifically, only some parameters are described here referring to the step 1 in the summary of the invention.

To parameter in the formula (2), α=β=1 is got in suggestion.

To the parameter in the formula (3), can carry out value as follows:

A. equal weight value.As get r ₀=r _{± 1}=r _{± 2}=r _{± 15}=... r _{± 15}=1.

B. linear weight value.As get r ₀=1, r _{± 1}=15/16, r _{± 2}=14/16 ..., r _{± 15}=1/15.

C. logarithm distribution probability value.As press following formula (6) value

$r_0={\&Integral;}_0^{1/2}p\left(x\right)\mathrm{dx}$

$r_{\mathrm{\&tau;}}={\&Integral;}_{\left|\mathrm{\&tau;}\right|-1/2}^{\left|\mathrm{\&tau;}\right|+1/2}p\left(x\right)\mathrm{dx}---\left(6\right)$

Wherein, p (x) is an exponential distribution: $p\left(x\right)=e^{-\frac{x}{\mathrm{\&sigma;}}},$ σ is that each footpath power need be according to sub-district concrete condition (radius of society, cell environment and channel condition etc.) value with respect to the attenuation coefficient of the first footpath power in the multipath channel.The method that the method is taked for suggestion.

2, divide the method for scrambler collection.Specifically, provide a kind of division example (numeral in the set is the numbering of scrambler in the TD-SCDMA standard) of scrambler collection here at the TD-SCDMA system referring to the step 2 in the summary of the invention.

SCS1:{0,4,25,26,28,29,33,39,41,42,48,52,54,56,84,89} (16)

SCS2:{1,5,7,10,15,20,40,46,47,49,61,64,75,82,118,126} (16)

SCS3:{2,3,6,11,12,17,22,23,34,35,36,38,45,50,65,86} (16)

SCS4:{8,9,13,14,18,19,24,27,32,37,44,67,70,104,116,117} (16)

SCS5:{16,21,30,31,43,59,78,85,92,94,99,105,107,109,124,125} (16)

SCS6:{63,66,72,79,93,95,106,110,113,123} (10)

SCS7:{73,74,90,98,103,111,114,119,121} (9)

SCS8:{55,60,71,83,87,112,115} (7)

SCS9:{57,77,81,88,96,97,101} (7)

SCS10:{62,68,69,76,108,122} (6)

SCS11:{53,80,91,100,120} (5)

SCS12:{51,58,102,127} (4)

3, the scrambling code distribution method the during network planning.Specifically, only some concrete network condition are provided the concrete scheme that scrambler distributes here referring to the step 3 in the summary of the invention.

By above-mentioned steps 2, whole 128 scramblers of TD-SCDMA system 12 scrambler collection have been divided into.When then determining the multiplexing factor Q of scrambler collection, the value that can choose has 3,4,7,9,12.

According to network condition, can be divided into following different situations:

A. the network of individual layer cell structure.Choosing value to the multiplexing factor Q of scrambler collection can be big as far as possible, as select Q=12, also can select less Q value as 3,4,7,9, for a part of scrambler resource is reserved in the follow-up network capacity extension.Q=3 and 7 scrambler allocation example are as depicted in figs. 1 and 2.Different cell clusters is with different color showings, the scrambler collection number under the scrambler that numeral is distributed of each bracket outside, sub-district, the label of the scrambler that the numeral of bracket the inside is distributed (being the label of the scrambler that provides in the TD-SCDMA standard).

B. the network of two-layer cell structure.Need be the multiplexing factor Q 1 of scrambler collection of every layer of cell selecting, Q2, and should make Q1+Q2＜=12.Fig. 3 has provided an example, the multiplexing factor Q 1=7 of scrambler collection that chooses for the low layer sub-district wherein, the multiplexing factor Q 2=4 of scrambler collection that chooses for high-rise sub-district.

4, divide the method for the channelization code set of a sub-district.Specifically, only some concrete network condition are provided concrete scheme of dividing different interference regions in the sub-district and the method for dividing channelization code set at an interference region here referring to the step 4 in the summary of the invention.

Divide the concrete scheme of different interference regions in the sub-district.According to different network condition, can be divided into following several situation:

A. do not dispose the sub-district of smart antenna.In this case, no matter antenna in cell is omnidirectional antenna or directive antenna (sectorized antennas), has only interference region, the i.e. Zone Full that the sub-district covered in the sub-district.Serious interference sub-district in this interference region is all adjacent sub-districts of sub-district therewith.Fig. 4 and Fig. 5 have provided the example under the both of these case respectively, and sub-district 1 (middle sub-district) has only an interference region A, the numeral in the bracket is the label of serious interfered cell (all neighbor cells) in this interference region A.

B. dispose the sub-district of smart antenna (antenna element is an omnidirectional antenna).In this case, can arrive the difference of angle or position, cell coverage area is divided into a plurality of interference regions, its serious sub-district of disturbing is determined in each zone according to signal.Can how much divide the interference region of different numbers according to smart antenna moulding numbers of beams purpose.Fig. 6 is 6 interference region A～F with the area dividing that sub-district 1 (middle sub-district) covers, and the label of the serious interfered cell of each interference region is annotated in bracket; Fig. 7 is 12 interference region A～L with the area dividing that sub-district 1 (middle sub-district) covers, and the serious interfered cell of A is 3,4, and the serious interfered cell of B is 4, and the serious interfered cell of C is 4,5, and the serious interfered cell of D is 5 ..., the rest may be inferred.

C. dispose the sub-district of smart antenna (antenna element is a directive antenna).In this case, equally, can arrive the difference of angle or position, cell coverage area is divided into a plurality of interference regions, its serious sub-district of disturbing is determined in each zone according to signal.Fig. 8 is divided into 6 interference region: A (3,4,5), B (2,3,4), C (7,2,3), D (6,7,2), E (5), F (6) with sub-district 1 (middle sub-district), and the numeral in the bracket is the serious interfered cell label of corresponding interference region.Equally, can how much divide the interference region of different numbers according to smart antenna moulding numbers of beams purpose.

Divide the method for channelization code set at each interference region.Determined the serious interfered cell of the interference region divided above, when dividing the channelization code set of certain interference region, only need be according to the cross-correlation performance of all spreading codes of all spreading codes of this sub-district and the serious interfered cell of this interference region, the cross-correlation performance is collected preferably collection in the channel code of relatively poor this interference region of conduct outward as the channel code of this interference region.With the interference region A among Fig. 6 is that example is divided its channelization code set, the serious interfered cell of A is known as sub-district 2,3,4, and the scrambler of sub-district 1,2,3,4 has been determined (known), at this moment according to the cross-correlation performance of all 48 spreading codes of 16 spreading codes of sub-district 1 and sub-district 2,3,4, be easy to just can divide channel code Wai Ji and the Nei Ji of interference region A.

5, be the method for user's assigns channelization codes of a sub-district.Specifically, only provide instantiation here referring to the step 5 in the summary of the invention.

As shown in Figure 9, the outer collection of channel code of establishing interference region A is CCSA1, and collection is CCSA2 in the channel code, and the rest may be inferred to interference region F; The annoyance level that neighbor cell is caused according to user present position difference can different these characteristics, and each interference region is divided into two kinds of zones: and the zone serious to neighbor cell interference (A1～F1) and the zone slight to neighbor cell interference (A2～F2).For the method for user's assigns channelization codes as follows: be in and answer the channel code in its zone of living in of priority allocation to collect outward that (CCSA1～CCSF1) is in the user in the slight zone of neighbor cell interference is answered the (CCSA2～CCSF2) of collection in the channel code in its zone of living in of priority allocation the user in the serious zone of neighbor cell interference.Be in regional A1 as certain user and then answer channel code among the priority allocation CCSA1, if certain user is in 2 channel codes of answering among the priority allocation CCSD2 of region D.

6, the dynamic allocation method of subscriber channel sign indicating number.Specifically, only provide instantiation here referring to the step 5 in the summary of the invention.

Still be example with Fig. 9, if certain user originally was in regional A2, for its distribution be channel code among the CCSA2, when it moves among the regional A1, should be it and redistribute channel code (unless the channel code among the CCSA1 is all occupied) among the CCSA1; If certain user originally was in area B 1, for its distribution be channel code among the CCSB1, when it moves in the zone C 1, should be it and redistribute channel code (unless the channel code among the CCSC1 is all occupied) among the CCSC1; The rest may be inferred for other situations.

Adopt scrambler of the present invention and channelization code allocation method, communication quality is significantly improved.Participate in Figure 10 (different spreading codes are to the performance curve under 3GPP Case11 channel, and wherein interfering signal power is 0.6 times of available signal power), and be explained as follows:

According to scrambler and the channelization code allocation method in the existing TD-SCDMA standard, scrambler 5 was in the different scrambler groups with scrambler in 10 minutes, therefore they can be assigned to two neighbor cells, if certain user in one of them sub-district is assigned with scrambler 5 and channel code 4 these spreading codes, the user of another sub-district is assigned with scrambler 10 and channel code 8 these spreading codes, and when two users are in the fringe region of two sub-districts, because the cross-correlation performance of these two spreading codes belongs to unacceptable class, can make two sub-districts be subjected to very strong interference simultaneously, communication performance very poor (referring to curve among Figure 10).

According to scrambling code distribution method of the present invention, scrambler 5 and scrambler 10 belong to scrambler collection SCS2, and these two scramblers can not be assigned to neighbor cell, can effectively avoid the appearance of above-mentioned situation thus.

Among Figure 10, scrambler does not all belong to same scrambler collection to two scramblers in any a pair of scrambler in (4,8), (6,10), (5,9), can be assigned to two adjacent sub-districts.Two users that are in fringe region when two adjacent sub-districts are assigned with spreading code to (scrambler 4+ channel code 2 as can be seen, scrambler 8+ channel code 2) time, because the cross-correlation performance of these two spreading codes belongs to a bad class, so communication performance still relatively poor (referring to curve among Figure 10).This problem can be solved by the distribution method of channel code among the present invention.When two adjacent sub-districts are assigned with scrambler 4 and scrambler 8, because the division of channelization code set in the division of interference region and the interference region, can simultaneously these two frequency spreading code division dispensings be in two users in this two cell edge region (promptly to the serious zone of disturbing of neighbor cell).Can effectively reduce the more strongly disturbing situation of this generation like this occurs.

This shows, adopt spreading code of the present invention (scrambler+channel code) distribution method, can make in the system user distributes in the serious interference region in sub-district spreading code and neighbor cell user's spreading code have cross-correlation performance preferably, thereby the presence of intercell interference in the reduction system greatly, improve communication quality (referring to curve among Figure 10), improve power system capacity.

Claims (4)

1, a kind of code-resource distribution method that reduces the code vision multiple address cellular mobile communication system interference, mainly be that whole spreading codes that CDMA Cellular System adopts are carried out the analysis of cross-correlation performance, and according to its characteristic, scrambler is divided into different scrambler collection, scrambler a little less than the cross correlation is distributed to adjacent sub-district, and the strong scrambler of cross correlation can be distributed in sub-district far away; On the basis of distributing cell scrambling, for this sub-district zones of different (optional) is divided different channel code Wai Ji and Nei Ji, for considering the interference size degree that it causes neighbor cell in the sub-district during user's assigns channelization codes, channel code in outer collection of channel code under its position/angle of dynamic assignment/zone or the interior collection, make between the employed spreading code of user of neighbor cell to have more weak cross correlation, its concrete steps are as follows:

(1) cdma cellular spreading code that mobile communication system adopts (scrambler+channel code) is carried out between any two the right cross-correlation performance analysis of spreading code, only to the spreading code under the different scrambling codes to carrying out the analysis of cross-correlation performance, and not to the spreading code under the same scrambler to carrying out the analysis of cross-correlation performance; Spreading code is drawn together cross-correlation performance analysis when synchronous and asynchronous to cross-correlation performance analysis package, establishes appropriate judgment criterion, the cross-correlation performance that spreading code is right is classified: good, bad, unacceptable;

(2) divide the scrambler collection: all scramblers are divided into several scrambler collection, all scramblers in the same scrambler collection all have the same or similar cross-correlation performance, all exist the unacceptable spreading code of cross-correlation performance right between any two scramblers in the same scrambler collection, and all do not exist the unacceptable spreading code of cross-correlation performance right between any two scramblers in the different scrambling codes collection;

(3) scrambler the during network planning distributes: according to the top scrambler collection of dividing, neighbor cell can not distribute the different scrambling codes in the same scrambler collection, if certain cell allocation a scrambler in certain scrambler collection, other scrambler in the same scrambler collection all can not be distributed in the sub-district that then is adjacent; The scrambler distribution ratio of non-adjacent sub-district is more flexible, can distribute the scrambler in the different scrambling codes collection, also can distribute the different scrambling codes in the same scrambler collection;

(4) channelization code set of a sub-district of division: determine the scrambler of certain sub-district and its neighbor cell by such scheme after, at first the All Ranges that this sub-district covers is divided into several interference regions according to signal arrival angle (DOA) or shape beam angle (optional), the division principle of interference region is that the signal of the user in the zones of different can cause serious interference to different neighbor cells, i.e. the property distinguished of serious interfered cell; Then at each interference region,, the channel code of current area is divided into different channelization code set according to the right cross-correlation performance of all spreading codes of serious interfered cell in this sub-district and this zone; Reach under angle (DOA) or the shape beam angle (optional) at certain signal, be called outer collection under this interference region, the stronger interior collection that is called under this interference region with the set of more weak this cell channelization sign indicating number of neighbor cell spreading code cross correlation;

(5) be user's assigns channelization codes of a sub-district: consider the interference size degree that the user causes neighbor cell, determine the annoyance level of user's signal in view of the above: seriously still slight to neighbor cell interference to neighbor cell interference to neighbor cell, answer the channel code under its place interference region of priority allocation to collect outward to the serious user of neighbor cell interference, but and to collecting in the channel code under slight its place interference region of user's priority allocation of neighbor cell interference;

(6) dynamic assignment of subscriber channel sign indicating number: the user position is not changeless, therefore distributes to user's channel code and should dynamically adjust according to customer location with to the neighbor cell interference degree; When the user when the slight zone of neighbor cell interference being moved to serious regional of neighbor cell interference, the channel code that is distributed need be adjusted into the channel code in the outer collection of channel code under its residing new interference region, vice versa; When the user moves to another interference region by certain interference region, for the channel code of its distribution also should be adjusted into the outer collection of channel code of its residing new interference region or the channel code in the interior collection.

2, the code-resource distribution method that disturbs of reduction code vision multiple address cellular mobile communication system according to claim 1 is characterized in that: can be in two kinds of situation during the channelization code set of dividing a sub-district:

A. adaptive antenna or intelligent antenna technology are not adopted in the sub-district, system can't know that user's signal arrives angle DOA information, then the division of the channelization code set of this sub-district does not need to consider that signal arrives angle DOA factor, be that the sub-district has only an interference region (all overlay areas), its serious sub-district of disturbing is its all neighbor cells, according to the right cross-correlation performance of all spreading codes of this sub-district and its all neighbor cells formation, all channel codes of this sub-district are divided into the subclass of two non-overlapping copies: this cell channelization sign indicating number that this cell channelization sign indicating number set that outer collection and neighbor cell spreading code cross correlation are more weak and interior collection and neighbor cell spreading code cross correlation are stronger is gathered;

B. adaptive antenna or intelligent antenna technology are adopted in the sub-district, system can know that user's signal arrives angle DOA information, then at first according to this reality of interference that can cause different neighbor cells under the different angles position in various degree, with the whole area dividing that the sub-district covered is several interference regions, and the signal of determining user in each interference region can cause the most several neighbor cells of serious interference, then at each interference region, according to the right cross-correlation performance of spreading code of disturbing all spreading codes of the most serious several sub-districts to form subscriber signal in the spreading code of this sub-district and this zone, all channel codes of this sub-district are divided into the subclass of two non-overlapping copies: Wai Ji and Nei Ji.

3, the code-resource distribution method that disturbs of reduction code vision multiple address cellular mobile communication system according to claim 1 is characterized in that: the signal of determining the user can carry out dividing region according to different measured values during to the annoyance level of neighbor cell:

A. the different zonings of pilot signal strength of the home cell that receives when the diverse location according to the user;

B. the different zonings of pilot signal strength of the neighbor cell that receives when the diverse location according to the user;

C. the different zonings of the pilot signal strength difference of home cell that receives when the diverse location according to the user and neighbor cell.

4, the code-resource distribution method that disturbs of reduction code vision multiple address cellular mobile communication system according to claim 1 is characterized in that: when determining that the user is in which interference region of this sub-district, can take diverse ways according to following two kinds of different situations:

A. adaptive antenna or intelligent antenna technology are not adopted in the sub-district, and system can't know that user's signal arrives angle DOA information, and then this sub-district has only an interference region, can determine that the user must be in this interference region;

B. adaptive antenna or intelligent antenna technology have been adopted in the sub-district, and system can know that user's signal arrives angle DOA information.Angle information in the time of then can arriving angle DOA and interference region division according to user's signal determines which interference region the user is in;

Then, be user's assigns channelization codes:, then answer the channel code under its place interference region of priority allocation to collect outward if the user is serious to neighbor cell interference; If the user is slight to neighbor cell interference, but collection in the channel code under its place interference region of priority allocation.

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