CN100596046C - Communication method and communication system - Google Patents
Communication method and communication system Download PDFInfo
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Abstract
The invention relates to a communication system, concretely a communicating method and system, adopting spread spectrum code multiple access technique, constructing enough spread spectrum code in a quasisynchronous system whose time error is limited in a certain range, so as to assure the capacity of the spread spectrum code division multiple access communication system, and realizing the spread spectrum code division multiple access communicating method and system which maintains enough users.
Description
One, technical field:
The present invention relates to a kind of communication system, more specifically be meant communication means and communication system, it adopts the spread spectrum code division multiple access technology, in the accurate synchro system that is limited to certain limit of time error, construct enough spreading codes, to guarantee the spread spectrum code division multiple access capability of communication system, realize the spread spectrum code division multiple access communication of the number of users that maintenance is enough.
Two, background technology:
In mobile communication system such as relevant mobile phone, often use spread spectrum (Spread Spectrum) code division multiple access (CDMA:Code Division Multiple Access) technology.The spread spectrum code division multiple access system is divided into Asynchronous Code Division Multiple Access (A-CDMA:Asynchronous CDMA) system usually and adopts S-CDMA (S-CDMA:Synchronous CDMA) system of orthogonal spectrum expansion communication mode.
Wherein, for the Asynchronous Code Division Multiple Access system, because the influence of the cross-correlation between the spreading code of each subscriber signal of differentiation, each user in the feasible communication simultaneously produces so-called multiple access mutually and disturbs (MAI:Multiple Access Interference).This multiple access disturbs, and can hinder the synchronous and demodulation that receives the user, finally causes the availability of frequency spectrum of system to descend.
On the other hand, adopt in the synchronous CDMA system of orthogonal spectrum expansion, each user's spread-spectrum signal is mutually orthogonal.Like this, the cross-correlation function value between the spreading code is zero, and multiple access disturbs and disappears, and is expected to improve the availability of frequency spectrum of mobile communication system.Certainly, in this so-called orthogonal spectrum expansion synchronous CDMA system, supposed that the spread-spectrum signal between each user is an ideal synchronisation; When synchronous error took place, its performance can sharply descend.Yet, in general wireless communication system, the error of synchronous circuit, radio wave airborne spread delay inequality, various factorss such as multidiameter delay can cause the synchronous error of user-user signal, and the synchro system of realizing ideal is very difficult.Wherein, if reduce multidiameter delay until less than 0.5 chip, one of spread spectrum major technology characteristics so: rake receives because the effective multipath signal of shortage becomes impossible.
For this reason, people have proposed a kind of quasi-synchronous CDMA (QS-CDMA:Quasi-Synchronous CDMA) system that allows the synchronous error in the certain limit to exist, caused that extensive concern (" of a specified duration open country etc.; " the quasi-synchronous CDMA modes of 2 value shift-register sequences "; the paper will-A of electronic communication association; vol97-A; № 1pp105-114; in January, 1996 " etc.) is in this quasi-synchronous CDMA system, used a kind of near initial point (be lock in time error limitation within the specific limits) have the spreading code of low cross-correlation function value, the synchronous spreading code of promptly so-called standard.Wherein, GMW sequence (Gordon-Mills-Welch sequence; " B.Gordon et.al., " Some new difference sets, " Canada J.Math.; vol.14, pp614-625,1984 " reference), particularly, meet the accurate spreading code synchronously of low cross-correlation function requirement just by the GMW sequence that same primitive polynomial generated.
Three, summary of the invention:
Problem to be solved by this invention
Above-mentioned quasi-synchronous CDMA system has possessed all good characteristics of spread spectrum code division multiple access technology.But in the realization of system, still some problem has to be solved.One of them is the number of users that how to guarantee system.
This problem just must be prepared abundant accurate spreading code synchronously, and system just can hold more user.Though and the above-mentioned GMW sequence from same primitive polynomial has good their cross correlation, the number of sign indicating number is considerably less.How finding the abundant spreading code with good their cross correlation is one of difficult problem of cdma system.
In view of the above problems, main purpose of the present invention is in the accurate synchro system that is limited to certain limit of time error, to construct abundant spreading code to guarantee the spread spectrum code division multiple access capability of communication system.
The means of dealing with problems
Learn that by present inventor's research all the year round the GMW sequence of same primitive polynomial cross-correlation function value on most of phase place is little, but the sequence number is considerably less; If select a pair of GMW sequence from these sequences, and one of them sequence carried out carrying out mould two stacks after certain phase deviation, can obtain a new sequence set, the cross-correlation function value between them is all very little about initial point.Wherein, phase pushing figure is determined by factors such as GWM sequence periods, and has been made of the sequence set of new sequence the new sequence that different side-play amounts obtain.These new sequences (after, be referred to as " GG sequence ") number, number (" the Biqi Long that has surpassed the GMW sequence widely, et.al., " A generalized QS-CDMAsystem and the design of new spreading code, " IEEE Trans.VT., vol 47, no.4,1998 " with reference to).
In addition, current research result by the inventor learns, GMW sequence set by same primitive polynomial generation, select a pair of GMW sequence can constitute the GG sequence set arbitrarily, plural number has then constituted a plurality of GG sequence set to the GMW sequence,, the sequence between the different GG sequence set might not continue to keep low cross-correlation function characteristic.It is as follows that sequence keeps the sequence set constructive method of good their cross correlation between a plurality of GG sequence set: select the right sequence of plural number from the GMW sequence of same primitive polynomial, it must be public that all sequence centerings have a GMW sequence; And by these GMW sequences to generating corresponding GG sequence set, between the GG sequence set, carry out suitable phase deviation simultaneously and obtain new sequence set.Certainly, new sequence set sequence number is the summation of the sequence number in above-mentioned a plurality of GG sequence set, and the sequence number increases greatly.In addition, current research result by the inventor learns, each sequence in GG sequence set is carried out suitable phase deviation, obtain a plurality of phase deviation sequence set of GG sequence, the sequence between these sequence set (comprising GG sequence originally) can keep good their cross correlation.By such method, we can obtain the new sequence set that the sequence number than a GG sequence set increases greatly.The present invention is based on above-mentioned achievement in research.
That is to say, communication means of the present invention is made up of following steps: in the spread spectrum code division multiple access system, the number one code parameters obtained of fixed primitive polynomial and the second different with it number arguments, in the parameter group set of the first phase-shift phase parameter and second phase-shift phase parameter composition, specify the parameter value of a parameter group, by aforementioned specified number one code parameters and fixed primitive polynomial generate a GMW sequence, by the aforementioned second specified number argument and fixed primitive polynomial generate the 2nd GMW sequence, undertaken after the phase deviation and carry out mould two addition computings obtaining specific new sequence by GMW sequence of the aforementioned specified first phase-shift phase parameter defined and the phase difference between the 2nd GMW sequence, phase pushing figure by the aforementioned specified second phase-shift phase parameter defined comes above-mentioned specific new sequence is carried out phase deviation, generate the accurate spreading code of spreading code synchronously that spread spectrum is used, adopt the synchronous spreading code of above-mentioned standard to carry out spread spectrum after signal send.
This communication means, at first be parameter setting method: comprise, generate the number one code parameters and second number argument of two GMW sequences, generate first required phase pushing figure parameter of GG sequence and the setting that generates the second required phase pushing figure parameter of new sequence.The establishing method of these parameters, by aforementioned new sequence constructive method of the present invention, determine in advance needed spreading code number and fixed primitive polynomial, design the parameter group (being designed spreading code corresponding parameters group) that constitutes by these four parameters.In communication process, selected one is not carried out the parameter setting in the parameter group of using.
Then, by the number one code parameters set point of appointment and fixed primitive polynomial, the GMW sequence generating method generates a GMW sequence.In addition, by the second number argument set point of appointment and fixed primitive polynomial, the GMW sequence generating method generates the 2nd GMW sequence.
Next, the method that generates specific new sequence (GG sequence) is, set phase difference between a GMW sequence and the 2nd GMW sequence by the first phase pushing figure parameter of appointment, according to phase difference the 2nd GMW sequence is carried out after the phase deviation two sequences and carry out mould two additions (sequence is synthetic) and just obtain specific new sequence.Then,, come above-mentioned GG sequence is carried out cyclic shift, obtain required accurate spreading code synchronously by the second phase pushing figure parameter of appointment according to generation method of spreading code of the present invention.Then, the spreading code that is generated by generation method of spreading code of the present invention carries out sequence spread spectrum generation spread-spectrum signal, sends.
As a result, when multi-user communication, even certain error lock in time is arranged, the cross correlation value between the spreading code of main user and other interference user is very little.The method according to this invention can constitute the spread spectrum code division multiple access communication system that allows certain lock in time of error.
The above-mentioned generation method of spreading code according to the present invention carries out cyclic shift by the phase pushing figure of the second phase pushing figure parameter setting to the GG sequence and obtains accurate spreading code synchronously.Yet these accurate afterbodys of spreading code synchronously append " a 0 " chip, and they just become orthogonal intersection.Thus, the spreading code after the orthogonalization is compared with original spreading code, and when lock in time, error was very little, it is lower that cross-correlation function value can become.
In addition, according to the present invention, the signal by aforesaid sending method sends after its reception, carries out despreading by the synchronous spreading code of aforesaid standard and handles.
In addition, according to the present invention, in aforesaid number one code parameters value and the aforesaid second number argument value, one of them must be fixed.
Communication system of the present invention is the spread spectrum code division multiple access system with sending part and acceptance division that adopts spectrum spreading method.Aforesaid transmitter: the number one code parameters obtained of fixed primitive polynomial and the second different with it number arguments, in the parameter group set of the first phase-shift phase parameter and second phase-shift phase parameter composition, specify the parameter value of a parameter group, by aforementioned specified number one code parameters and fixed primitive polynomial generate a GMW sequence, by the aforementioned second specified number argument and fixed primitive polynomial generate the 2nd GMW sequence, undertaken after the phase deviation and carry out mould two addition computings obtaining specific new sequence by GMW sequence of the aforementioned specified first phase-shift phase parameter defined and the phase difference between the 2nd GMW sequence, phase pushing figure by the aforementioned specified second phase-shift phase parameter defined comes above-mentioned specific new sequence is carried out phase deviation, generate the accurate spreading code of spreading code synchronously that spread spectrum is used, adopt the synchronous spreading code of above-mentioned standard to carry out spread spectrum after signal send.
This communication system at first is the designation method of number one code parameters value, the second number argument value, the first phase pushing figure parameter value, the second phase pushing figure parameter value.Next is, by the number one code parameters set point of appointment and fixed primitive polynomial, the GMW sequence generating method generates a GMW sequence.In addition, by the second number argument set point of appointment and fixed primitive polynomial, the GMW sequence generating method generates the 2nd GMW sequence.
Then be the generation method of specific new sequence: set phase difference between a GMW sequence and the 2nd GMW sequence by the first phase pushing figure parameter of appointment, according to phase difference the 2nd GMW sequence is carried out after the phase deviation two sequences and carry out mould two additions (sequence is synthetic) and just obtain specific new sequence.Then,, come above-mentioned GG sequence is carried out cyclic shift, obtain required accurate spreading code synchronously by the second phase pushing figure parameter of appointment according to generation method of spreading code of the present invention.Then, the spreading code that is generated by generation method of spreading code of the present invention carries out sequence spread spectrum generation spread-spectrum signal, sends.
That is to say that communication system of the present invention communication means according to the present invention communicates.The method according to this invention can constitute one, when allowing certain lock in time of error, guarantees the spread spectrum code division multiple access communication system of enough multi-user's numbers.
The acceptance division of communication system of the present invention receives the signal that is sent by aforesaid sending method, and carries out despreading by the synchronous spreading code of aforesaid standard and handle.
Four, description of drawings:
Accompanying drawing 1 is the communication system skeleton diagram of the first embodiment of the present invention
Accompanying drawing 2 is transmitter pie graphs of accompanying drawing 1 base station
Accompanying drawing 3 is pie graphs of the receiver of accompanying drawing 1 base station
Accompanying drawing 4 is transmitter pie graphs of accompanying drawing 1 portable terminal
Accompanying drawing 5 is pie graphs of the receiver of accompanying drawing 1 portable terminal
Accompanying drawing 6 is pie graphs of a kind of distortion of spreading code maker
Accompanying drawing 7 is pie graphs of the transmitter of second embodiment
Accompanying drawing 8 is pie graphs of the receiver of second embodiment
Five, embodiment:
" first embodiment "
1 the first embodiment of the present invention is described to accompanying drawing 5 with reference to the accompanying drawings.As shown in the drawing, the symbol that same parts indicated is the same, and omits to some extent when explanatory note.
Accompanying drawing 1 is the synoptic diagram of the communication system 100 of the relevant first embodiment of the present invention.As shown in Figure 1, communication system 100 is that the portable terminal 20 that carries out radio communication by communication network 90, a plurality of base stations 10 that link to each other with communication network 90, with certain base station 10 is constituted.In this communication system, certain portable terminal 20, by the base station 10 of sub-district, place, communication network 90 communicates with other sub-district, and finally arrives the portable terminal 20 in other sub-district.Certainly, general communication network 90 is connected on the networks such as public telecom network, the Internet, and portable terminal can communicate with other communication equipments that are connected on these networks.
The composition of each base station, comprise antenna 11, the duplexer 12 that links to each other with this antenna, in addition, comprise that also the duplexer 12 that has antenna 11 is connected with the transmitter 13S that sends signals to portable terminal 20, and the receiver 13R of the duplexer 12 that has an antenna 11 and received signal processing joins.Simultaneously, base station 10 also comprises the controller of realizing with communication network 90 14 that interface is controlled and base station system is controlled.
Above-mentioned transmitter 13S as shown in Figure 2, its composition comprises 1) the transmission information bit BSB that comes self-controller 14 is carried out symbol-modulated, the modulator 31 of output modulation signal BMS; 2) the number one code parameters value BFN that provides according to controller 14, the second number argument value BSN, the first phase pushing figure parameter value BFS, the second phase pushing figure parameter value BSS and transmission BSY lock in time, the spreading code maker 35 of generation spreading code SC; 3) the spreading code SC that adopts spreading code maker 35 to provide, the modulation signal BSM that modulator 31 provides carries out the spread spectrum modulator 32 that band spectrum modulation generates spread-spectrum signal BSG and outputs to duplexer 12.In addition, contents such as carrier modulation, radio frequency processing have also been omitted in the accompanying drawing.
Above-mentioned spreading code maker 35, its composition comprises: 1) the number one code parameters value BFN that provides according to controller 14 and send signal Synchronization time BSY generates the GMW sequence generator 41 of a GMW sequence FGS
12) the second number argument value BSN that provides according to controller 14 and send signal Synchronization time BSY generates the 2nd GMW sequence generator 41 of the 2nd GMW sequence SGS
2And the generation of two GMW sequences is based on same primitive polynomial.Certainly, can generate a plurality of GMW sequences by this primitive polynomial.By the appointment of the number one code parameters value and the second number argument value, we obtain a required GMW sequence and the 2nd GMW sequence.
The composition of spreading code maker 35 also comprises: 3) the spreading code number of chips of the first phase pushing figure B parameter FS appointment that provides according to controller 14, the 2nd GMW sequence SGS that the 2nd GMW sequence generator is provided carries out cyclic shift, generates first phase shifter 43 of shift sequence SSG; 4) the 2nd GMW sequence SSG after a GMW sequence FGS and the displacement synthesizes (mould two additions), generates the synthesizer 44 of GG sequence GGS; 5) second phase shifter 45 of cyclic shift is provided the GGS sequence that is provided by synthesizer 44 the specified number of chips of the second phase pushing figure B parameter SS that provides according to controller.
The composition of the receiver 13R of last note comprises as shown in Figure 3: 1) transmission BSY lock in time that provides with reference to controller 14, the received signal BRS that is provided by duplexer 12 is carried out synchronously, and generate the synchronizer 53 of BRY lock in time; 2) BRY lock in time that provides according to synchronizer 53, and the number one code parameters BFN that provides of controller 14, the second number argument BSN, the first phase pushing figure B parameter FS and the second phase pushing figure B parameter SS generate the spreading code maker 35 of the spreading code SC that be used for despreading consistent with aforementioned spreading code SC; 3) the spreading code SC that adopts spreading code maker 35 to provide, the received signal BRS that duplexer 12 is provided carries out the despreading processing, obtains the despreader 51 of despread signal BMR; 4) the despread signal BMR that is provided by despreader 51 is carried out symbol demodulation, and generate information bit BRB, simultaneously the demodulator of exporting to controller 14 52.In addition, parts such as carrier wave demodulation, radio frequency processing have also been omitted in the accompanying drawing.
The composition of above-mentioned transmitter 23S comprises: 1) the transmission information bit MSB that is provided by controller 24 is modulated, generate the modulator 31 of modulation signal MMS; 2) the number one code parameters MFN that provides according to controller 24, the second number argument MSN, the first phase pushing figure parameter MFS, the second phase pushing figure parameter MSS and MRY lock in time that provided by receiver 23R generate the spreading code maker 35 of spreading code SC; 3) the spreading code SC that utilizes spreading code maker 35 to provide carries out band spectrum modulation to the modulation signal MMS that is provided by modulator 31, and generates transmission signal MSG, delivers to the spread spectrum modulator 32 of duplexer 22.That is to say the structure basically identical of the transmitter 23S here and the transmitter 13S of base station.
Above-mentioned receiver 23R comprises 1 as shown in Figure 5) the received signal MRS that is provided by duplexer 22 generates the synchronizer 53 of lock in time; 2) MRY and controller number one code parameters MFN, the second number argument MSN, the first phase pushing figure parameter MFS, the second phase pushing figure parameter MSS that provide lock in time that provides based on synchronizer 53 generates the spreading code maker 35 of spreading code SC; 3) the spreading code SC that utilizes spreading code maker 35 to provide carries out despreading to the received signal MRS that is provided by duplexer 22, generates the despreader 51 of despread signal MMR; 4) despread signal MMR is carried out symbol demodulation, and generate the demodulator 52 that reception information bit MRB outputs to controller 24.That is to say the structure basically identical of the receiver 23R here and the receiver 13R of above-mentioned base station 10.
The communication system 100 of the foregoing description, base station 10 adopts the spread spectrum code division multiple access method to communicate with portable terminal 20.Its prerequisite is that the spreading code that base station 10 and portable terminal 20 use is by base station 10 unified distributions.By other Common Control Channel, base station 10 notifies each portable terminal their spreading code.
The number of users of work when in addition, mobile communication system will determine at first that system is required.In view of the above, controller 14 generates the parameter group that four parameters of spreading code required number one code parameters BFN, the second number argument BSN, the first phase pushing figure B parameter FS, the second number offset parameter BSS are formed.In the parameter group of present embodiment, number one code parameters BFN fixes; For every couple of BFN and BSN, the first phase pushing figure B parameter FS can get some suitable values.Certainly, according to a pair of BFN and BSN, the first phase pushing figure B parameter FS can find the solution in advance.In addition, present embodiment, for every couple of BFN and BSN, the second phase pushing figure parameter can be got some suitable values, forms the set of parameter group like this.In a word, the purpose of handling like this is in order to keep near the low cross-correlation function value initial point between all spreading codes.
Here, their spreading codes of using of base station 10 and the portable terminal that communicates with 20 are determined by primitive polynomial, number one code parameters, second number argument, the first phase pushing figure parameter, the second phase pushing figure parameter.In these parameters, primitive polynomial is predetermined, is kept at base station 10 and portable terminal 20.Then, when needs are set up communication link with portable terminal 20, a vacant spreading code will be distributed in base station 10.That is to say, the set of the parameter group of forming from number one code parameters, second number argument, the first phase pushing figure parameter, the second phase pushing figure parameter, select a parameter group of not using for use.
At first, the action of base station 10 to the down channel of portable terminal 20 described.As shown in Figure 2, in the down channel, the controller 14 of base station 10 provides number one code parameters BFN, the second number argument BSN, the first phase pushing figure B parameter FS, the second phase pushing figure B parameter SS and transmission BSY lock in time to spreading code maker 35.
At spreading code maker 35, the number one code parameters BFN that provides by controller 14 and lock in time BSY, a GMW sequence generator 41
1To generate GMW sequence FGS continuously.Meanwhile, the second number argument BSN that provides by controller 14 and lock in time BSY, the 2nd GMW sequence generator 41
2To generate GMW sequence SGS continuously.By predetermined primitive polynomial, common GMW sequence generating method (B.Gordon et.al., " Some new difference sets is abideed by in the generation of these GMW sequences, " Canada J.Math., vol.14, pp614-625,1984 references).
Then, first phase-shifter carries out cyclic shift to the 2nd GMW sequence SGS, and shift amount is determined by the first phase pushing figure B parameter FS that controller 14 provides, and generates the SSG signal after being shifted.Thus, between the 2nd GMW sequence SSG after a GMW sequence FGS and the displacement, exist by the specified phase difference of the first phase pushing figure B parameter FS.
Next the 2nd GWM sequence SSG after 44 pairs the one GMW sequences of synthesizer FGS and the displacement synthesizes, and generates new sequence GGS.Then, according to the specified number of chips of the second phase pushing figure B parameter SS that slave controller 14 provides, the new sequence GGS that synthesizer 44 is provided carries out cyclic shift, has generated spreading code SC.
At spreading code maker 35, the spreading code SC of Sheng Chenging is output to frequency multiplier 32 like this.
When spreading code SC generated, by means of communication network 90, the transmission information bit that is come by other base stations 10 transmission was to modulator 31 outputs.Then, 31 pairs of modulators send information bit and carry out symbol-modulated, generate modulation signal BMS.
At frequency multiplier 32, modulation signal carries out band spectrum modulation by spreading code SC, generates to send signal BSG.Certainly, offer between the modulation signal BMS of frequency multiplier 32 and the spreading code SC and must carry out synchronously by controller 14.
The transmission signal BSG that generates sends to portable terminal 20 by duplexer 12, antenna 11 backs successively.
The wireless signal that base station 10 sends, antenna 21 receptions by portable terminal 20 by duplexer 22, form received signal MRS and also offer receiver 23R (with reference to accompanying drawing 5).Because down channel is a synchronizing channel of nature, lock in time, error was only caused by the multidiameter delay difference.At this moment maximum lock in time of error equals maximum multipath time delay poor (Tmd).
At portable terminal 20, the received signal MRS by duplexer 22 outputs delivers to synchronizer 53 and despreader 51.Synchronizer 53 is handled by MRS to received signal and is obtained MRY lock in time, and it is delivered to spreading code maker 35 and transmitter 23S in the receiver 23R.
Spreading code maker 35 also receives number one code parameters MFN, the second number argument MSN of self-controller 24, the parameter setting of the first phase pushing figure parameter MFS, the second phase pushing figure parameter MSS when receiving MRY lock in time.These four parameter values, the parameter value that adopts with the spreading code maker 35 of above-mentioned base station 10 transmitter 13S is consistent.Thus, the spreading code maker 35 here will generate same spreading code SC with the spreading code maker 35 of above-mentioned base station 10 transmitter 13S, and offer despreader 51.
The spreading code SC that adopts spreading code maker 35 to provide, despreader 51 MRS to received signal carries out despreading, generates despread signal MMR to demodulator 52 outputs.
Next, 52 couples of despread signal MMR of demodulator carry out symbol demodulation, generate to receive information bit MRB, and to controller 24 outputs.
Afterwards, the controller 24 butt joint breath bit MRB that collect mail carry out necessary processing, show by display 26 as required or export voice.
The following describes the communication process that sends the up channel of signal by portable terminal 20 to base station 10.As shown in Figure 4, the communication process of up channel is, at first, provide by receiver 23R lock in time MRY as sending the spreading code maker 35 that offers transmitter 23S lock in time; Simultaneously, controller 24 provides number one code parameters MFN, the second number argument MSN, the first phase pushing figure parameter MFS, the second phase pushing figure parameter MSS for transmitter 23S.These four parameter values, with the parameter value that the spreading code maker 35 of above-mentioned base station 10 transmitter 13S uses should be in full accord.Like this, according to received signal lock in time and this four parameter values, the spreading code maker 35 of transmitter 23S will generate the spreading code SC same with the spreading code maker 35 of the transmitter 13S of above-mentioned base station 10.The spreading code SC of Sheng Chenging like this outputs to the frequency multiplier 32 of transmitter 23S.
Meanwhile, from the transmission information bit MSB of representatives such as the voice signal of loader 25 or data message, by modulator 31 outputs of controller 24 to transmitter 23S.Subsequently, the same with the processing of the transmitter 13S of above-mentioned base station 10, send information bit MSB after treatment, generate and send signal MSG, through duplexer 22 and antenna 21, send wireless signals to base station 10.
As shown in Figure 3, the wireless signal of portable terminal 20,10 are received by antenna 11 in the base station, generate received signal BRS through duplexer 12, offer the receiver 13R of base station 10.In the communication of up channel, each portable terminal 10 is because the different asynchronism(-nization)s that arrive base station 10 of the time delay of radio wave propagation cause error lock in time between each portable terminal signal.Simultaneously, always there is certain synchronous error in Shi Ji synchronous circuit.Take all factors into consideration all factors, the worst error of up channel lock in time as the formula (1).
Δtu
max＝T
md+T
pd+T
je (1)
Here, T
MdBe the maximum of multidiameter delay difference, T
PdBe the maximum (coming and going) of radio wave propagation delay inequality, T
JeIt is the synchronous error maximum of synchronous circuit.We can design Δ tu in advance
Max, as the permissible range of quasi-synchronous CDMA system synchronization time error, the just accurate simultaneously design considerations of spreading code synchronously.
In the base station 10, the received signal BRS of duplexer output offers synchronizer 53 and the despreader 51 of receiver 13R.After synchronizer carries out time synchronized, generate and receive BRY lock in time.
Number one code parameters BFN, the second number argument BSN, the first phase pushing figure B parameter FS, the second phase pushing figure B parameter SS of reception BRY lock in time and controller offer spreading code maker 35.These four parameter values are consistent with the parameter group of the spreading code maker 35 of the transmitter 13S of above-mentioned base station 10.Like this, according to receiving BRY and the spreading code maker 35 of these four pre-set parameters lock in time, will generate the spreading code SC same, and output to despreader 51 with the spreading code maker 35 of the transmitter 13S of above-mentioned base station 10.
Then, same with the receiver 23R of portable terminal 20, received signal BRS obtains receiving information bit BRB and outputs to controller 14 through handling.
Next, the controller butt joint is collected mail and is ceased the bit analyzing and processing, and necessary words transmit to other base stations 10 by communication network.
As mentioned above, present embodiment by a plurality of GMW sequences that same primitive polynomial generates, can be constructed near the little spreading code of cross-correlation function value initial point in a large number.And therefrom choose and distribute to each communication link of base station and portable terminal, as spreading code, realize spread spectrum code division multiple access communication.In a word, under situation, still guarantee abundant number of users, realize the spread spectrum code division multiple access technology with certain lock in time of error.
Among the first above-mentioned embodiment, the cycle of the spreading code of employing is determined by the GMW sequence period that deciding primitive polynomial generates, but is not orthogonal intersection.Afterbody at the spreading code of the foregoing description adds one " 0 ", then becomes orthogonal intersection.Carried out orthogonalized spreading code, compared with above-mentioned spreading code, under the very little situation of error lock in time, the cross-correlation function between the spreading code is littler.And this orthogonalization process only needs to append one " 0 " at the afterbody of the spreading code of second phase-shifter output.
In addition, among first embodiment of last note, the second number argument BSN (MSN) is variable.But it also can be fixed up, and at this moment, by changing the value of the first phase pushing figure BFS (MFS), can obtain new sequence (GG sequence) group.Simultaneously, under the situation that satisfies error permissible range condition lock in time, can be by changing the second phase pushing figure B parameter SS (MSS), promptly the sequence in the sequence set is carried out cyclic shift (shift amount is specified by the second phase pushing figure parameter value), just obtain more spreading code, still keep good their cross correlation between them.
In addition, a kind of distortion spreading code maker 35 ' of the spreading code maker 35 among first embodiment of last note, it constitutes as shown in Figure 6.That is to say, spreading code maker 35 ', the same with spreading code maker 35, comprise: 1) number one code parameters BFN (MFN) is provided and sends BSY lock in time (reception MRY lock in time that receiver 23R provides), generate the GMW maker 41 of a GMW sequence FGS according to controller 14 (24)
1With; 2) the second number argument BSN (MSN) is provided and sends BSY lock in time (reception MRY lock in time that receiver 23R provides) according to controller 14 (24), generate the 2nd GMW maker 41 of the 2nd GMW sequence SGS
23) value that is provided with of the first phase pushing figure B parameter FS ' that provides according to controller 14 (24) (MFS ') is to by a GMW sequence generator 41
1A GMW sequence FGS who provides carries out cyclic shift, generates first phase-shifter 431 of the GMW sequence SFG after being shifted; 4) value that is provided with of the second phase pushing figure B parameter SS ' that provides according to controller 14 (24) (MSS ') is to by the 2nd GMW sequence generator 41
2The 2nd GMW sequence SGS that provides carries out cyclic shift, generates second phase-shifter 432 of the 2nd GMW sequence SSG after being shifted; 5) the shift sequence SSG of the shift sequence SFG of the sequence of a GMW sequence and the 2nd GMW sequence carries out mould two additions (merging), generates the synthesizer 44 of spreading code SC.
Two phase pushing figure B parameter FS ' of spreading code maker 35 ' (MFS ') and BSS ' (MSS '), can carry out conversion suc as formula (2), (3) with two phase pushing figure B parameter FS (MFS) of the foregoing description and BSS (MSS), the spreading code of convert back spreading code maker 35 ' and 35 generations of spreading code maker is consistent.
BFS(MFS)＝BSS’(MSS’)-BFS’(MFS’) (2)
BSS(MSS)＝BFS’(MFS’) (3)
" embodiment 2 "
Next, the second embodiment of the present invention describes with reference to accompanying drawing 7,8.That present embodiment adopts is accurate SMCC CDMA (Code Division Multiple Access) (MC-DS-CDMA:Multi-Carrier Direct Spread CDMA), and can carry out the RAKE merging by receiving multipath signals.Compare with first embodiment, the formation of transmitter 13S (23S) and receiver 13R (23R) is roughly the same, but different part is also arranged.Stress dissimilarity below.
The transmitter 13S (23S) of present embodiment comprises as shown in Figure 7: 1) sending information bit BSB (MSB) serial to parallel conversion is BSP
1～BSP
M(MSP
1～MSP
M) serial-parallel converter 61 Hes; 2) spreading code maker 35 Hes of generation spreading code SC; 3) each information bit BSP
j(MSP
j) (j=1～M) is transformed into wavelet modulation signal BPC
j(MPC
j) transmission wavelet modulator 65j; 4) wavelet signal BPC
j(MPC
j) synthesize the signal synthesizer 63 that multi-carrier spread spectrum sends signal BSG (MSG).
Each of last note sends wavelet modulator 65
j, comprising: 1) the information bit BSP that serial-parallel converter 61 is provided
j(MSP
j) modulate, generate symbol-modulated signal BMP
j(MMP
j) modulator 31 Hes; 2) the spreading code SC that adopts spreading code maker 35 to provide is to symbol-modulated signal BMP
j(MMP
j) carry out band spectrum modulation, and generate modulated spread spectrum signal BPS
j(MPS
j) frequency multiplier 32 Hes; 3) the modulated spread spectrum signal BPS that frequency multiplier 32 is provided
j(MPS
j) to carry out carrier wave be f
jThe wavelet modulator 66 of wavelet modulation.
In addition, the receiver 13R (23R) of present embodiment comprises as shown in Figure 8: 1) the received signal BRS (MRS) that is provided by duplexer 12 (22) is carried out synchronously, generate synchronizer 53 Hes of BRY lock in time (MRY); 2) has the spreading code SC that the generation despreading is used
1～SC
LSpreading code maker 35
1～35
LSpreading code maker 79., spreading code SC
1～SC
LWith the same spreading code of above-mentioned spreading code SC, be its shift sequence a plurality of of equal value; 3) BRS (MRS) handles by each wavelet to received signal, generates the reception information bit BRP of each wavelet
1～BRP
M(MRP
1～MRP
M) reception wavelet signal processor 75
1～75
MWith; 4) the reception information bit BRP of each wavelet
1～BRP
M(MRP
1～MRP
M) carry out the parallel to serial converter 73 that parallel serial conversion generate to receive information bit BRB (MRB).
Each of last note receives wavelet signal processor 75, comprising: 1) carry out the wavelet demodulation with frequency f j, generate wavelet restituted signal BPR
j(MPR
j) wavelet demodulator 76 Hes; 2) adopt spreading code SC
1～SC
LTo wavelet restituted signal BPR
j(MPR
j) despreader 51 that carries out despreading
1～51
LWith; 3) output signal of despreader is synthesized, generate RAKE composite signal BRR
j(MRR
j) RAKE synthesizer 77 Hes; 4) to RAKE composite signal BRR
j(MRR
j) meet demodulation, generate and receive information bit BRP
jDemodulator 78.
As the communication system 100 of above-mentioned embodiment, send information bit BSB (MSB) at transmitter 13S (23S), generate the symbol sebolic addressing BSP of a plurality of (M) through serial-parallel converter 61
j(MSP
j).Then, each symbol sebolic addressing BSP
j(MSP
j) carry out symbol-modulated at modulator 31, carry out band spectrum modulation by spreading code SC, generate spread-spectrum signal BPS
j(MPS
j).Spread-spectrum signal BPS
j(MPS
j) carry out the wavelet modulation through wavelet modulator 66, and synthesize by signal synthesizer 63, generate multi-carrier spread spectrum and send signal BSG (MSG), subsequently, send signal BSG (MSG) through duplexer 12 (22) and characteristic 11 (21), send to the other side who communicates by letter.
Send signal BSG (MSG), after antenna 11 (21) and duplexer 12 (22) receptions, carry out the wavelet demodulation at the wavelet demodulator 76 that receives wavelet processor 75 at communication counterpart.Then, wavelet restituted signal BPR
j(MPR
j), generate spreading code SC by spreading code maker 79
1～SC
LCarry out despreading, carry out RAKE at the RAKE synthesizer and synthesize.Next, RAKE composite signal BRR
j(MRR
j) carry out demodulation through meeting demodulator 78, and, generate the reception information bit BRB (MRB) of series connection form by parallel to serial converter 73.
Present embodiment, the chip-spaced of spreading code SC (Tc:Chip Duaration), as the formula (4).
Tc＝(Tb/N)×M (4)
Here, Tb is the input information bits interval, and N is the cycle of spreading code, and M is the wavelet number.In addition, work as M=1, then become common single-carrier system.
So,, then become formula (5) if lock in time, error was unit with the chip
L1＝<Δtu
max/Tc> (5)
Here, Δ tu
MaxSuc as formula (1) define＜X the expression X is rounded up.
In addition, the multipath number of maximum possible, as the formula (6)
L2＝<Tmd/Tc> (6)
As top explanation, present embodiment, similarly to Example 1, a plurality of GMW sequences by same primitive polynomial generation, construct the little spreading code of a lot of cross-correlation function values, and distribute to base station and communications of Mobile Terminals link, carry out the spread spectrum code division multiple access technical communication.So, adopting spreading code of the present invention, the limits synchronization time error obtains good multiple access interference characteristic in the scope on one point, and has enough yardages to guarantee number of users, realizes spread spectrum code division multiple access communication.
Further, lock in time, error L1 must be in the scope that the synchronous spreading code SC of standard is allowed, and simultaneously, multipath is counted L2 also must be greater than 1.The employing of the accurate SMCC CDMA technology of present embodiment is in that moving in recent years/the more and more higher very little situation of information bit interval T b that causes of radio communication system data speed is little, and it is easy that system design becomes.
That is to say that when information bit shortened at interval, it is big that error L1 meeting lock in time (relatively) becomes at single-carrier system.And the multicarrier system of present embodiment then can be counted M by regulating wavelet, makes that lock in time, error L1 got a suitable value.The accurate MC-DS-CDMA system synchronously of design because it is little to have adopted the synchronous spreading code multiple access of standard of the present invention to disturb, and has the abundant spreading code system that makes can guarantee high power capacity like this.Simultaneously, can utilize RAKE to receive the rake technology makes system have good anti fading performance.
In addition, for present embodiment, also can be the same with first embodiment, adopt the distortion of spreading code maker 35.
In addition, the same with second embodiment in first embodiment, can have the RAKE receiving function of receiving multipath signals.
The present invention also comprises various may the distortion.
The effect of invention: such as top detailed description, according to communication means of the present invention, at certain error model lock in time In enclosing, can keep the spread spectrum code division multiple access technology of abundant number of users.
In addition, according to communication system of the present invention, use communication means of the present invention, in certain error range lock in time In, the spread spectrum code division multiple access communication of the number of users of realizing keeping abundant.
Claims (7)
1. communication means, adopt the spread spectrum code division multiple access technology, it is characterized in that: communication means is made up of following steps: the number one code parameters obtained of fixed primitive polynomial and the second different with it number arguments, in the parameter group set of the first phase-shift phase parameter and second phase-shift phase parameter composition, specify the parameter value of a parameter group, by aforementioned specified number one code parameters and fixed primitive polynomial generate a GMW sequence, by the aforementioned second specified number argument and fixed primitive polynomial generate the 2nd GMW sequence, undertaken after the phase deviation and carry out mould two addition computings obtaining specific new sequence by GMW sequence of the aforementioned specified first phase-shift phase parameter defined and the phase difference between the 2nd GMW sequence, phase pushing figure by the aforementioned specified second phase-shift phase parameter defined comes above-mentioned specific new sequence is carried out phase deviation, generate the accurate spreading code of spreading code synchronously that spread spectrum is used, adopt the synchronous spreading code of above-mentioned standard to carry out spread spectrum after signal send.
2. a kind of communication means according to claim 1, it is characterized in that: described generation method of spreading code is the value of aforesaid number one code parameters, the value of aforesaid second number argument, the value of the aforesaid first phase-shift phase parameter, in the parameter combinations of the value of the aforementioned second phase-shift phase parameter, first and second number arguments pair are right with first and second offset parameters, at least wherein two a pair of parameters are inconsistent, the specific new sequence that generates and carry out phase deviation after the accurate spreading code synchronously that obtains, add one " 0 " at its afterbody, make the orthogonalized orthogonalization method of these spreading codes.
3. a kind of communication means according to claim 1 and 2 is characterized in that: the signal of described sending method for sending receives at receiving terminal, and carries out despreading by above-mentioned accurate spreading code synchronously.
4. a kind of communication means according to claim 1 and 2 is characterized in that: in the described number one code parameters and second number argument, it must be fixed value that a side is arranged.
5. an application rights requires the communication system of any described communication means in 1～4, described communication system constitutes by communication network, a plurality of base stations that link to each other with communication network and with portable terminal that radio communication is carried out in certain base station, in this communication system, certain portable terminal, base station, communication network by the sub-district, place, communicate with other sub-district, and finally reach portable terminal in other sub-district; Described base station is made up of antenna (11), duplexer (12), transmitter (13S), receiver (13R) and controller (14), antenna links to each other with duplexer, having the duplexer of antenna is connected with the transmitter (13S) that sends signal to portable terminal, having the duplexer of antenna and the receiver (13R) of received signal processing simultaneously joins, it is characterized in that: its composition of described transmitter (13S) comprises: 1) the transmission information bit BSB that comes self-controller (14) is carried out symbol-modulated, the modulator (31) of output modulation signal BMS; 2) the number one code parameters value BFN that provides according to controller (14), the second number argument value BSN, the first phase pushing figure parameter value BFS, the second phase pushing figure parameter value BSS and transmission BSY lock in time, the spreading code maker (35) of generation spreading code SC; 3) the spreading code SC that adopts spreading code maker (35) to provide, the modulation signal BMS that modulator (31) provides carries out the spread spectrum modulator (32) that band spectrum modulation generates spread-spectrum signal BSG and outputs to duplexer (12).
6. a kind of communication system according to claim 5, it is characterized in that: described spreading code maker, comprise: 1) the number one code parameters value BFN that provides according to controller (14) and send signal Synchronization time BSY generates the GMW sequence generator (411) of a GMW sequence FGS; 2) the second number argument value BSN and the transmission signal Synchronization time BSY that provides according to controller (14), generate the 2nd GMW sequence generator (412) of the 2nd GMW sequence SGS, and, the generation of two GMW sequences is based on same primitive polynomial, certainly, can generate a plurality of GMW sequences by this primitive polynomial, by the appointment of the number one code parameters value and the second number argument value, we obtain a required GMW sequence and the 2nd GMW sequence; 3) the spreading code number of chips of the first phase pushing figure B parameter FS appointment that provides according to controller (14), the 2nd GMW sequence SGS that the 2nd GMW sequence generator is provided carries out cyclic shift, generates first phase shifter (43) of shift sequence SSG; 4) the 2nd GMW sequence SSG after a GMW sequence FGS and the displacement synthesizes, and generates the synthesizer (44) of GG sequence GGS; 5) second phase shifter (45) of cyclic shift is provided the GGS sequence that is provided by synthesizer (44) the specified number of chips of the second phase pushing figure B parameter SS that provides according to controller.
7. according to claim 5 or 6 described a kind of communication systems, it is characterized in that: described receiver (13R), comprise: 1) transmission BSY lock in time that provides with reference to controller (14), the received signal BRS that is provided by duplexer (12) is carried out synchronously, generate the synchronizer (53) of BRY lock in time; 2) BRY lock in time that provides according to synchronizer (53), and the number one code parameters BFN that provides of controller (14), the second number argument BSN, the first phase pushing figure B parameter FS and the second phase pushing figure B parameter SS generate the spreading code maker (35) of the spreading code SC that be used for despreading consistent with aforementioned spreading code SC; 3) the spreading code SC that adopts spreading code maker (35) to provide, the received signal BRS that duplexer (12) is provided carries out the despreading processing, obtains the despreader (51) of despread signal BMR; 4) the despread signal BMR that is provided by despreader (51) is carried out symbol demodulation, and generate information bit BRB, simultaneously the demodulator of exporting to controller (14) (52).
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| CN112118025A (en) * | 2015-08-21 | 2020-12-22 | 宜春市等比科技有限公司 | Method for spreading spectrum by using 4b/6b technology and 4 pseudo-random codes |
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| 移动通信原理与系统. 严常青，1-2，44-57，61，99-100，重庆大学出版社. 2002 |
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