CN1832381B - Method for improving ultilization ratio of orthogonal variable extended frequency factor code tree - Google Patents
Method for improving ultilization ratio of orthogonal variable extended frequency factor code tree Download PDFInfo
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Abstract
This invention discloses a method for increasing the usability of an orthogonal variable spread spectrum factor code tree including searching for the occupied distributable code words of the brother code words under each stage of spread spectrum factors in the code tree as the code word fragments, processing each pair of fragments as follows: re-configuring users occupying brother code words of the first fragment in said pair of fragments into a second code word fragment in it and merging the brother code words of the first fragment released by the user and said first fragment to code words of the upper stage spread spectrum factors, which can merge the code word fragments in the OVSF code tree to father codes with less spread spectrum factors to further increase the usability of OVSF code tree.
Description
Technical field
The present invention relates to Wideband Code Division Multiple Access (WCDMA) (WCDMA, Wideband Code Division MultipleAccess) mobile communication technology field, especially the method that relates to a kind of raising orthogonal variable frequency extension factor code (OVSF, Orthogonal Variable Spreading Factor codes) code tree utilance.
Background technology
Because the WCDMA system is a kind of code division multiple access system, so the sub-district down physical channel is to rely on down channel sign indicating number separately to distinguish in this system, this just requires to keep quadrature between different physical channels use respectively in the sub-district the down channel sign indicating number, and when guaranteeing to have orthogonality between the down channel sign indicating number that different physical channels use, also to satisfy the requirement of different business, promptly require down physical channel to want variable message transmission rate can be provided different service quality QoS.For satisfying above-mentioned requirements, the WCDMA system adopts orthogonal variable frequency extension factor code OVSF as channel code, thereby realize having orthogonality between the down channel sign indicating number that different down physical channels use respectively, simultaneously because the spreading factor of ovsf code is variable, so applicable to the requirement of down physical channel to the variable data transmission rate.
See also Fig. 1, this figure is the composition structural representation of ovsf code tree in the prior art, and wherein each channel code can be used C
SF, kCome unique expression, wherein SF is the spreading factor of this channel code, and k is channel code sequence number (0≤k≤SF-1).In ovsf code tree, be quadrature between the identical channel code of spreading factor SF; And be nonopiate between the different channel code of spreading factor SF, promptly father's sign indicating number and subcode are nonopiate; Have fraternal each other code word between the channel code of identical father's sign indicating number, as shown in Figure 1, channel code C
2,0Be C
4,0And C
4,1Father's sign indicating number (otherwise, i.e. channel code C
4,0And C
4,1Be C
2,0Subcode), channel code C
2,1Be C
4,2And C
4,3Father's sign indicating number (otherwise, i.e. channel code C
4,2And C
4,3Be C
2,1Subcode), and channel code C
4,0And C
4,1Fraternal each other code word.
Wherein assignable channel code should satisfy following two conditions in the ovsf code tree:
(1) path from this assignable channel code to ovsf code tree root node does not have channel code to be assigned with;
(2) in ovsf code tree, not have channel code to be assigned with in this assignable channel code subtree that is root node.
Ovsf code tree is as shown in Figure 1 formed structure, if channel code C
2,0Be assigned with, so channel code C
4,0And C
4,1Just can not be assigned with, because channel code C
4,0And C
4,1Do not satisfy above-mentioned condition (1); And if channel code C
4,0Or C
4,1Be assigned with, so channel code C
2,0Just can not be assigned with, because channel code C
2,0Do not satisfy above-mentioned condition (2).
Form the structure as can be seen from ovsf code shown in Figure 1 tree simultaneously, the spreading factor SF at different levels of ovsf code tree are 2
n, and the spreading factor SF that uses in the WCDMA system is from 4 to 512.If be corresponding spreading factor SF that the message transmission rate of 512 code word support is normalized to " 1 " in ovsf code tree, the maximum data transfer rate of so whole ovsf code tree support is 2
9, so spreading factor SF is that 4,8,16,32,64,128,256, the 512 following corresponding respectively message transmission rates of supporting of a code word are 2
7, 2
6, 2
5, 2
4, 2
3, 2
2, 2,1.If hypothesis spreading factor SF in ovsf code tree is that the number of the allocatable channel sign indicating number below 4,8,16,32,64,128,256,512 is respectively a like this
1, a
2, a
3, a
4, a
5, a
6, a
7, a
8, the supported maximum data transfer rate of then current code tree is a
1* 2
7+ a
2* 2
6+ a
3* 2
5+ a
4* 2
4+ a
5* 2
3+ a
6* 2
2+ a
7* 2+a
8
Because it is the message transmission rate of the whole subtree support of root node that the characteristic of ovsf code tree, the message transmission rate of one of them assignable channel code support have been represented with this assignable channel code, such as: channel code C
1,0The message transmission rate of supporting is 2
9, this also is the maximum data transfer rate that whole ovsf code tree is supported, so spreading factor SF is 8 following allocatable channel number of codes a in the following formula
2Do not comprise that spreading factor SF is the allocatable channel number of codes below 4.Ovsf code tree is as shown in Figure 1 formed in the structure, if channel code C
4,0, C
4,1, C
4,2All can be assigned with, and channel code C
8,7Be assigned with, spreading factor SF has 7 channel code to be assigned with below 8 so, but for to satisfy the condition that the allocatable channel sign indicating number should satisfy, corresponds to a in the above-mentioned formula
1Should be 3, and a
2Should be 7; Allocatable channel number of codes below the subsequent stages spreading factor SF by that analogy.
As fully visible, the channel code that spreading factor is little can be supported higher message transmission rate, and can further be split into the bigger code word of spreading factor, therefore the channel code importance that spreading factor is little in the ovsf code tree is bigger, divide timing carrying out channel code, under the requirement of satisfying channel data transmission speed, should keep the little channel code of spreading factor in the ovsf code tree, so that provide service for system more flexibly as far as possible.Ovsf code tree is as shown in Figure 1 formed in the structure, if channel code C
4,0Can be assigned with channel code C
4,1, C
4,2, C
8,7Be assigned with, at this moment distributing a spreading factor SF if desired is 8 channel code, and plurality of distribution method: channel code C is then arranged
8,0, C
8,1, C
8,6All can be assigned with, and distributing channel mode C
8,6Then be best choice, because if distributing channel mode C
8,0Or C
8,1The capital causes his father's sign indicating number C
4,0Can not be assigned with, when the spreading factor SF that need reallocate is 4 channel code, system can't satisfy (because channel code C so again
4,1, C
4,2Be assigned with, and channel code C
8,7Be assigned with and caused his father's sign indicating number C
4,3Can not be assigned with again); And distributing channel mode C
8,6Then can not cause above-mentioned drawback, because channel code C
8,7Be assigned with, caused his father's sign indicating number C
4,3(also be channel code C simultaneously
8,7Father's sign indicating number) can not be assigned with distributing channel mode C so again
8,6Just can not cause an assignable spreading factor SF is that 4 channel code becomes and can not distribute, thus when to need to distribute a spreading factor SF again be 4 channel code, and C
4,0Just distributive condition can have been satisfied.
Though at present can be in the WCDMA system by using rational code assignment algorithm, reach the purpose of when distributing channel mode, accomplishing as far as possible to keep the code word that spreading factor is little in the ovsf code tree, but because each user inserts the randomness of sub-district and each user continues duration in the sub-district randomness, therefore along with the increase in system's continuous working period, in the ovsf code tree of respective cell code word " fragment " phenomenon will inevitably appear.If ovsf code tree goes up the code word fragment too much then can influence the utilance of code tree, become the littler assignable father's sign indicating number of spreading factor because these code word fragments can't merge with fraternal code word again, this will disagree with the principle of above-mentioned " keeping the little code word of spreading factor in the ovsf code tree " as far as possible.Such as in ovsf code tree, initially having spreading factor SF is that 4 channel code below 4 can be assigned with, and the follow-up spreading factor SF that inserted successively is n user 128 below in the sub-district, supposes that the channel code that these access users take respectively is C
128,0To C
128, n-1Continuous n code word, and follow-up user to withdraw from not be to withdraw from one by one according to the access order, as inserting the user and n access user withdrawed from the sub-district when the 1st, then can cause channel code C
128,0And C
128, n-1Become idle code word, but because the idle code word C that gets off
128,0And C
128, n-1Therefore be the subcode that belongs to different father's sign indicating numbers respectively, can't merge into a spreading factor and be 64 code word, also will cause code word C simultaneously
128,0And C
128, n-1Father's sign indicating number separately all can't be assigned with.And in the ideal case, if idle these two code word C that get off
128,0And C
128, n-1Can merge, be 64 distribution codeword but so just can merge a spreading factor, and it is that 64 code word can't be utilized that promptly this unfavorable situation has just caused a spreading factor.Above-mentionedly thisly can not merge the code word that becomes corresponding father's sign indicating number with fraternal code word and be referred to as code word " fragment ", the code word C that gets off as the above-mentioned free time
128,0And C
128, n-1All belong to the code word fragment.
In the WCDMA system, the channel code resource management scheme has only been paid close attention to the code assignment algorithm at present, and the code word fragment of how handling in the ovsf code tree is not considered, so the utilance of ovsf code tree also can't reach desirable level with regard to corresponding.
Summary of the invention
The technical problem to be solved in the present invention is to propose a kind of method that improves orthogonal variable frequency extension factor code code tree utilance, becomes the littler father's sign indicating number of spreading factor so that the code word fragment in the ovsf code tree can merge, with better raising ovsf code tree utilance.
For addressing the above problem, the present invention proposes a kind of method that improves orthogonal variable frequency extension factor code code tree utilance, comprise step:
(1) in advance every grade of spreading factor is provided with fragment order of severity threshold value;
(2) but search in the described code tree the occupied distribution codeword of the fraternal code word under the spreading factors at different levels as the code word fragment by traveling through described code tree;
(3) add up the code word number of chips that finds under the spreading factors at different levels respectively;
According to the corresponding fragment order of severity value of calculating under every grade of spreading factor of the code word number of chips under every grade of spreading factor;
At every grade of spreading factor, whether judge its fragment order of severity value greater than the fragment order of severity threshold value that sets in advance for it, if every pair of code word fragment under this grade spreading factor is carried out subsequent step (4a) and processing (4b); Otherwise the code word fragment under this grade spreading factor is not handled;
(4) respectively every pair of code word fragment under every grade of spreading factor is carried out following processing:
(4a) will take this user and be reconfigured to this second code word fragment in the code word fragment to the fraternal code word of the first code word fragment in the code word fragment;
(4b) the fraternal code word of the first code word fragment that this user is discharged and the described first code word fragment merge the code word that becomes under the upper level spreading factor.
Wherein said detailed process according to code word number of chips calculating fragment order of severity value comprises:
Calculate the maximum data transfer rate sum that each code word fragment can be supported in the described code tree;
The maximum data transfer rate of using described maximum data transfer rate sum can support divided by each code word under the minimal frequency spreading factor rounds the quotient that obtains as the desirable code word number of chips under the described minimal frequency spreading factor;
The rest may be inferred, at follow-up following each grade spreading factor, use described maximum data transfer rate sum to deduct the product of the maximum data transfer rate that each code word can be supported under desirable code word number of chips under the top spreading factor at different levels and the respective stages spreading factor one by one, maximum data transfer rate with the difference that obtains can be supported divided by each code word under this grade spreading factor rounds the quotient that obtains as the desirable code word number of chips under this grade spreading factor;
Deduct desirable code word number of chips under this grade spreading factor with the code word number of chips under every grade of spreading factor, obtain fragment order of severity value under this grade spreading factor divided by this grade spreading factor with obtaining two times of difference.
Respectively every pair of code word fragment under every grade of spreading factor is carried out step (4a) and processing (4b) according to the descending order of spreading factor in the wherein said step (4).
The ascending value of above-mentioned spreading factor is followed successively by 4,8,16,32,64,128,256,512.
Every grade of ascending spreading factor 8, spreading factor 16, spreading factor 32, spreading factor 64, spreading factor 128, spreading factor 256 and spreading factor 512 of comprising respectively of spreading factor described in the step (4).
The present invention improves the method for orthogonal variable frequency extension factor code code tree utilance by searching the code word fragment in the ovsf code tree, and the user that the code word fragment under each grade spreading factor SF is carried out taking the fraternal code word of a code word fragment is reconfigured on another code word fragment, the fraternal code word of this code word fragment that this user is discharged and this code word fragment merge the processing that becomes the code word under the upper level spreading factor SF then, thereby can realize the code word fragment in the ovsf code tree is merged the purpose that becomes the littler father's sign indicating number of spreading factor SF, therefore the corresponding littler code word of how assignable spreading factor SF that also just can increase has improved the utilance of ovsf code tree preferably.
Simultaneously, the judging process to the fragment order of severity that the present invention proposes calculates easy, is easy to realize; And propose to begin to finish to the one-level of spreading factor SF minimum by the one-level of spreading factor SF maximum, the reformation of carrying out the code word fragment step by step merges to be handled, thus the reformation that can improve the code word fragment merges treatment effeciency.
Description of drawings
Fig. 1 is the composition structural representation of ovsf code tree in the prior art;
Fig. 2 is the main realization principle flow chart that the present invention improves the method for ovsf code tree utilance;
Fig. 3 is the specific implementation process flow chart that the present invention improves the method for ovsf code tree utilance;
Fig. 4 is that the present invention improves in the method for ovsf code tree utilance the distribution condition schematic diagram of code word fragment on the code tree;
Fig. 5 utilizes the inventive method to reform code tree state schematic diagram after handling of the code word fragment in the ovsf code shown in Figure 4 tree.
Embodiment
The method that the present invention improves orthogonal variable frequency extension factor code code tree utilance is at inserting at random and the randomness of duration of inserting the user in the sub-district along with user in the sub-district in the prior art, can cause occurring and to merge the code word fragment that become the father's sign indicating number under the upper level spreading factor SF with occupied fraternal code word in the ovsf code tree of this sub-district, therefore can reduce the problem of ovsf code tree utilance, search processing and proposed corresponding code word fragment, weigh the processing of the ovsf code tree fragment order of severity and by reformation code word fragment, so that the code word fragment on the ovsf code tree can merge the processing that becomes the littler code word of spreading factor SF, with the utilance of further raising ovsf code tree.
The most typical application of method that the present invention improves orthogonal variable frequency extension factor code code tree utilance is the WCDMA mobile communication system, when the performance that the present invention is improved the method for orthogonal variable frequency extension factor code code tree utilance describes in detail below is example to be applied in the WCDMA system all, and wherein the value of spreading factor SF is from 4～512 in the WCDMA system.
See also Fig. 2, this figure is the main realization principle flow chart that the present invention improves the method for ovsf code tree utilance; Its main implementation procedure is as follows:
Step S10 searches the code word fragment under the spreading factor SF at different levels in the current ovsf code tree, and wherein the code word fragment has had clear and definite definition in the above-mentioned background technology, but is the occupied distribution codeword of fraternal code word, as shown in Figure 1, if code word C
4,0By CU, and C
4,0Fraternal code word C
4,1Not by CU, but also be in distribution state, then the code word C here
4,1Be spreading factor SF in the ovsf code tree and be the code word fragment under 4.
Wherein can search code word fragment under the spreading factor SF at different levels by the mode that travels through ovsf code tree step by step among the step S10.
Step S20, according among the step S10 to the lookup result of the code word fragment under the spreading factor SF at different levels in the ovsf code tree, respectively every pair of code word fragment under every grade of spreading factor SF is carried out following processing:
Be reconfigured to this to the second code word fragment in the code word fragment with taking this user, go to then and carry out subsequent step S30 the fraternal code word of the first code word fragment in the code word fragment;
Step S30, the fraternal code word of the first code word fragment that this user among the step S20 is discharged and this first code word fragment merge the code word that becomes upper level spreading factor SF under, i.e. and merging becomes the corresponding father's sign indicating number under the little SF of upper level.As shown in Figure 1, be that 8 following code word fragments are respectively C if find SF
8,0And C
8,4, then can will take C
8,0Brother's code word C
8,1The user be reconfigured to code word fragment C
8,4On, be about to assignable code word fragment C
8,4Distribute to and take code word C originally
8,1The user so that this user discharges the code word C that took originally
8,1, so just can be with code word fragment C
8,0The code word C that discharges with this user
8,1(be code word fragment C
8,0Fraternal code word) merge that to become upper level SF be father's sign indicating number C below 4
4,0Thereby, can realize handling father's sign indicating number obtaining below the littler one-level of spreading factor SF by reshuffling and merging, consistent with the principle that keeps the code word that spreading factor is little in the ovsf code tree of WCDMA system requirements as far as possible.
Wherein above-mentionedly can carry out respective handling among step S20 and the step S30 to every pair of code word fragment under every grade of spreading factor SF respectively according to the descending order of spreading factor SF; Promptly begin the reformation merging processing of code word fragment from the bottom one-level branch of ovsf code tree, the rest may be inferred, upwards carries out step by step, until the tree root place, can improve the efficient that the code word fragment is reformed and handled in the ovsf code tree like this.Because the SF value in the WCDMA system is from 4～512, so in the WCDMA system, the reformation of being carried out the code word fragment by the SF level of maximum step by step merges processing, when SF is 4 one-level, just be that 44 following code words are all thought the code word fragment with SF, these 4 code word fragments are no longer carried out handling to the merging of upper level, promptly no longer are that code word fragment merging the becoming SF below 4 is 2 following father's sign indicating numbers with SF, because there is no need for the WCDMA system.
See also Fig. 3 below, this figure is the specific implementation process flow chart that the present invention improves the method for ovsf code tree utilance; Its main implementation process is as follows:
Step S100 is provided with fragment order of severity threshold value to every grade of spreading factor SF in the ovsf code tree in advance, is that 16 one-level fragment order of severity threshold value is 20% as setting in advance spreading factor SF in the ovsf code tree;
Step S110 travels through current ovsf code tree, searches the code word fragment under the spreading factor SF at different levels in this code tree;
Step S120 according to the lookup result of step S110, adds up the code word number of chips that finds under the spreading factor SF at different levels respectively; As:
By traveling through current ovsf code tree, but search the distribution codeword that can not merge with fraternal code word as the code word fragment, add up code word number of chips under every grade of SF respectively according to different spreading factors, it to spreading factor 4 code word, because its merging that can not make progress again of WCDMA system constraint, so but SF is 4 distribution codeword all is the code word fragment.As: can suppose that spreading factor in the ovsf code tree is that the statistics number of 4,8,16,32,64,128,256,512 code word fragment is respectively a
1, a
2, a
3, a
4, a
5, a
6, a
7, a
8
As shown in Figure 4, this figure is that the present invention improves in the method for ovsf code tree utilance the distribution condition schematic diagram of code word fragment on the code tree, and spreading factor SF is the code word C under 16 among the figure
16,0, C
16,2And C
166Respectively by CU, according to the definition of above-mentioned code word fragment, their fraternal code word C separately
16,1, C
16,3And C
16,7It all is the code word fragment; In like manner, spreading factor SF is the code word C under 8
8,2It also is the code word fragment; Spreading factor SF is the C under 4
4,2And C
4,3It also is the code word fragment.Then can add up and obtain spreading factor is that 16 code word number of chips is 3, and spreading factor is that 8 code word number of chips is 1, and spreading factor is that 4 code word number of chips is 2.
Step S130, according among the step S120 to the corresponding fragment order of severity value of calculating under every grade of spreading factor of the statistics of the code word number of chips under every grade of spreading factor SF;
It is as follows wherein to calculate the detailed process of fragment order of severity value of corresponding every grade of SF according to the code word number of chips of every grade of SF:
1) calculates the maximum data transfer rate sum that each code word fragment can be supported in the ovsf code tree, being applied in the WCDMA system with this method is example, supposes that above-mentioned to obtain spreading factor in the ovsf code tree be that the statistics number of 4,8,16,32,64,128,256,512 code word fragment is respectively a
1, a
2, a
3, a
4, a
5, a
6, a
7, a
8, the maximum data transfer rate sum that each code word fragment can be supported in the then current ovsf code tree is:
S＝a
1×2
7+a
2×2
6+a
3×2
5+a
4×2
4+a
5×2
3+a
6×2
2+a
7×2+a
8
2) maximum data transfer rate that the maximum data transfer rate sum S that is tried to achieve use 1) can support divided by each code word under the minimal frequency spreading factor SF, the quotient that obtains is rounded as the desirable code word number of chips under this minimal frequency spreading factor, because in the WCDMA system, the SF minimum value is 4, so SF is that the maximum data transfer rate that each code word under 4 can be supported is 2
7, then SF is that 4 desirable code word number of chips is:
b
1=[S/2
7] b
1Expression SF is 4 desirable code word number of chips;
3) the rest may be inferred, at follow-up following each grade spreading factor of this ovsf code tree (is that SF is 8 in the WCDMA system, 16,32,64,128,256,512), use 1) in the maximum data transfer rate sum S that tried to achieve deduct the product of the maximum data transfer rate that each code word can be supported under desirable code word number of chips under the top spreading factor at different levels and the respective stages spreading factor one by one, maximum data transfer rate with the difference that obtains can be supported divided by each code word under this grade spreading factor rounds the quotient that obtains as the desirable code word number of chips under this grade spreading factor; As in the WCDMA system, follow-up spreading factor is that the desirable code word number of chips under 8,16,32,64,128,256,512 is as follows respectively:
b
2＝[(S-b
1×2
7)/2
6]
b
3＝[(S-b
2×2
6-b
1×2
7)/2
5]
b
4＝[(S-b
3×2
5-b
2×2
6-b
1×2
7)/2
4]
b
5＝[(S-b
4×2
4-b
3×2
5-b
2×2
6-b
1×2
7)/2
3]
b
6＝[(S-b
5×2
3-b
4×2
4-b
3×2
5-b
2×2
6-b
1×2
7)/2
2]
b
7＝[(S-b
6×2
2-b
5×2
3-b
4×2
4-b
3×2
5-b
2×2
6-b
1×2
7)/2]
b
8＝[S-b
7×2-b
6×2
2-b
5×2
3-b
4×2
4-b
3×2
5-b
2×2
6-b
1×2
7]
This shows, by above-mentioned 1) in each code word fragment can be supported in the ovsf code tree of trying to achieve maximum data transfer rate sum S just can calculate the ideally desirable code word number of chips of spreading factors at different levels, wherein b
1To b
8The desirable code word number of chips of representing spreading factor from 4 to 512 in the WCDMA system respectively; Here need to prove: even the code word fragment that can merge in the current ovsf code tree is all merged, also may have the code word fragment on code tree, code word number of chips in this case is called desirable code word number of chips; And above-mentioned a
1, a
2, a
3, a
4, a
5, a
6, a
7, a
8The actual code word number of chips of representing every grade of spreading factor respectively.
4) deduct desirable code word number of chips (representing) under this grade spreading factor with the code word number of chips (representing) under every grade of spreading factor obtaining of statistics among the step S120 with b with a, obtain fragment order of severity value under this grade spreading factor with two times of the gained difference divided by this grade spreading factor SF, fragment order of severity value is (a-b) * 2/SF.
Fragment order of severity value for the code words at different levels of spreading factor in the WCDMA system from 8 to 512 also just can be expressed as (a-b) * 2/SF so; Code word fragment situation with ovsf code shown in Figure 4 tree is an example, can be that 16 the code word fragment order of severity is calculated to SF according to the aforementioned calculation process, and process is as follows:
The maximum data transfer rate sum that each code word fragment can be supported in this ovsf code tree is:
S＝2×2
7+1×2
6+3×2
5；
Wherein SF is that 4 desirable code word number of chips is:
b
1＝[S/2
7]＝[2×2
7+1×2
6+3×2
5/2
7]＝3；
SF is that 8 desirable code word number of chips is:
b
2＝[(S-b
1×2
7)/2
6]＝[(2×2
7+1×2
6+3×25-3×2
7)/2
6]＝0；
SF is that 16 desirable code word number of chips is:
b
3＝[(S-b
2×2
6-b
1×2
7)/2
5]＝[(2×2
7+1×2
6+3×2
5-0-3×2
7)/2
5]＝1；
Then SF is that 16 code word fragment order of severity value is (a
3-b
3) * 2/SF=(3-1) * 2/16=25%.
Step S140, at the code word fragment of the maximum one-level of spreading factor SF in the current ovsf code tree (in the WCDMA system, be SF be 512 one-level), whether judge this grade fragment order of severity value greater than the fragment order of severity threshold value that sets in advance for this grade, if carry out subsequent step S150; Otherwise carry out subsequent step S170.After promptly drawing fragment order of severity value under the spreading factors at different levels through said process, just the one-level from the spreading factor maximum begins judgement, if the fragment order of severity value of the maximum one-level of this SF is the fragment order of severity threshold value of its setting in advance greater than system, the code word fragment situation of ovsf code tree as shown in Figure 4, if for SF is that the 16 fragment order of severity threshold values that are provided with are 20%, because the above-mentioned SF that tried to achieve is that 16 fragment order of severity value is 25%, then eligible need be that code word fragment under 16 is reformed to merge and handled to spreading factor.
Step S150, carry out following processing at every pair of code word fragment under this grade spreading factor:
Be reconfigured to this to the second code word fragment in the code word fragment with taking this user to the fraternal code word of first code word in the code word fragment; Promptly in the code word fragment that needs are reformed, select its fraternal code word by the first code word fragment of CU, select another code word fragment again, reshuffle the user of the fraternal code word that takies the first code word fragment, its is discharged formerly take code word and remove to take another code word fragment of selection.Repeat this process, till can't selecting reconfigurable user.
Ovsf code tree code word fragment situation as shown in Figure 4, wherein SF is the code word C under 16
16,1,C
16,3And C
16,7All be the code word fragment, at first select code word fragment C
16,1, its fraternal code word C
16,0By CU; Select another code word fragment C again
16,3,, take code word C so can reshuffle because it is an assignable code word
16,0The user, make the code word C of its release busy
16,0And remove to take assignable code word fragment C
16,3, code word fragment C like this
16,1With its fraternal code word C
16,0Just can merge and handle.Select next code word fragment C again
16,7,,, be 16 one-level code word fragment reforming process end this time for this SF so it can't be merged because there has not been another corresponding code word fragment to exist.
Step S160, the fraternal code word of the first code word fragment that above-mentioned this user is discharged and this first code word fragment merge becomes the littler code word of upper level spreading factor; The code word code word fragment corresponding with it that discharges after promptly reshuffling the user successfully merges becomes the littler code word of upper level spreading factor.Ovsf code tree code word fragment situation as shown in Figure 4 by the reconfiguration process of top step, is under 16 the situation at SF, through to taking code word C
16,0The user carry out reconfiguration process, code word C
16,0To be released, the user will be configured to and take code word fragment C
16,3, d/d like this code word C
16,0With code word fragment C
16,1To become SF be distribution codeword C below 8 but just can merge
8,0Go to execution in step S180 then;
Step S170, code word fragment under this grade spreading factor is not handled, because it is the fragment order of severity threshold value of its setting in advance that the fragment order of severity value of this grade SF does not surpass, promptly the code word fragment under this grade SF is not very serious, therefore consider the operation resource of system, will no longer reform to merge in this case and handle the code word fragment of this grade; Go to execution in step S180 then;
Step S180, the fragment order of severity value that continues to judge the upper level spreading factor whether greater than the fragment order of severity threshold value that sets in advance for it (in the WCDMA system, maximum SF is that to be SF be 256 one-level for 512 upper level), if be back to continuation execution in step S150 and step S160 at the code word fragment under this grade SF; Otherwise be back to continuation execution in step S170 at the code word fragment under this grade SF.
Repeat above-mentioned steps S150, S160, S170 and S180 like this, at 4 o'clock till being no longer to adjudicate to spreading factor, because spreading factor is the merging processing that can't make progress again of 4 code word in the WCDMA system.
See also Fig. 5, this figure utilizes the inventive method to reform code tree state schematic diagram after handling of the code word fragment in the ovsf code shown in Figure 4 tree, shown in the figure in the current ovsf code tree SF be 16 code word C
16,2, C
16,3, C
16,6By CU, and spreading factor SF is 8 code word C
8,0Being assignable code word owing to merge to handle to have become, is that distribution codeword below 8 is by an original code word C but make SF
8,2Become to two present code words and be respectively C
8,0And C
8,2, and do not have influence on the user to the taking of sign indicating number resource, so also with regard to the corresponding code word utilance that has improved the ovsf code tree.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (5)
1. a method that improves orthogonal variable frequency extension factor code code tree utilance is characterized in that, comprises step:
(1) in advance every grade of spreading factor is provided with fragment order of severity threshold value;
(2) but search in the described code tree the occupied distribution codeword of the fraternal code word under the spreading factors at different levels as the code word fragment by traveling through described code tree;
(3) add up the code word number of chips that finds under the spreading factors at different levels respectively;
According to the corresponding fragment order of severity value of calculating under every grade of spreading factor of the code word number of chips under every grade of spreading factor;
At every grade of spreading factor, whether judge its fragment order of severity value greater than the fragment order of severity threshold value that sets in advance for it, if every pair of code word fragment under this grade spreading factor is carried out subsequent step (4a) and processing (4b); Otherwise the code word fragment under this grade spreading factor is not handled;
(4) respectively every pair of code word fragment under every grade of spreading factor is carried out following processing:
(4a) will take this user and be reconfigured to this second code word fragment in the code word fragment to the fraternal code word of the first code word fragment in the code word fragment;
(4b) the fraternal code word of the first code word fragment that this user is discharged and the described first code word fragment merge the code word that becomes under the upper level spreading factor.
2. the method for raising orthogonal variable frequency extension factor code code tree utilance as claimed in claim 1 is characterized in that, described detailed process according to code word number of chips calculating fragment order of severity value comprises:
Calculate the maximum data transfer rate sum that each code word fragment can be supported in the described code tree;
The maximum data transfer rate of using described maximum data transfer rate sum can support divided by each code word under the minimal frequency spreading factor rounds the quotient that obtains as the desirable code word number of chips under the described minimal frequency spreading factor;
The rest may be inferred, at follow-up following each grade spreading factor, use described maximum data transfer rate sum to deduct the product of the maximum data transfer rate that each code word can be supported under desirable code word number of chips under the top spreading factor at different levels and the respective stages spreading factor one by one, maximum data transfer rate with the difference that obtains can be supported divided by each code word under this grade spreading factor rounds the quotient that obtains as the desirable code word number of chips under this grade spreading factor;
Deduct desirable code word number of chips under this grade spreading factor with the code word number of chips under every grade of spreading factor, obtain fragment order of severity value under this grade spreading factor divided by this grade spreading factor with obtaining two times of difference.
3. the method for raising orthogonal variable frequency extension factor code code tree utilance as claimed in claim 1, it is characterized in that, respectively every pair of code word fragment under every grade of spreading factor is carried out step (4a) and processing (4b) according to the descending order of spreading factor in the described step (4).
4. as the method for any described raising orthogonal variable frequency extension factor code of the claim code tree utilance of claim 1～3, it is characterized in that the ascending value of described spreading factor is followed successively by 4,8,16,32,64,128,256,512.
5. the method for raising orthogonal variable frequency extension factor code code tree utilance as claimed in claim 4, it is characterized in that every grade of ascending spreading factor 8, spreading factor 16, spreading factor 32, spreading factor 64, spreading factor 128, spreading factor 256 and spreading factor 512 of comprising respectively of spreading factor described in the step (4).
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| JP2004129037A (en) * | 2002-10-04 | 2004-04-22 | Japan Telecom Co Ltd | Device for allocating orthogonal variable diffusion coefficient code |
| CN1527518A (en) * | 2003-09-19 | 2004-09-08 | 中兴通讯股份有限公司 | Channel code list renormalizing method for WCDMA system |
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| JP2004129037A (en) * | 2002-10-04 | 2004-04-22 | Japan Telecom Co Ltd | Device for allocating orthogonal variable diffusion coefficient code |
| CN1527518A (en) * | 2003-09-19 | 2004-09-08 | 中兴通讯股份有限公司 | Channel code list renormalizing method for WCDMA system |
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