CN105188122A - Method for controlling mine tunnel uplink multi carrier-code division multiple access (MC-CDMA) subcarrier power - Google Patents

Abstract

The invention discloses a method for controlling mine tunnel uplink time frequency coded cooperation multi carrier-code division multiple access (MC-CDMA) subcarrier power. Round robin distribution is performed on a subcarrier of an uplink time frequency coded cooperation MC-CDMA spread spectrum branch, and the subcarrier on the spread spectrum branch is eliminated according to a preset proportion by use of the signal to noise ratio corresponding to each time frequency coded cooperation MC-CDMA subcarrier fed back to the sending terminal by a receiving terminal, so that the subcarrier power control transmission is realized. A discrete subcarrier is allocated for each mine tunnel uplink time frequency coded cooperation MC-CDMA spread spectrum branch according to fixed intervals, so that the problem of low total user channel capacity caused by low transmission quality of exceptional spread spectrum branch is solved. Furthermore, the use ratio of the MC-CDMA transmitting power can be improved, time frequency coded cooperation MC-CDMA frequency diversity gain is fully used, communication reliability of the time frequency coded cooperation MC-CDMA wireless transmission system is improved, and error rate performance of the user is improved.

Description

A kind of mine laneway up MC-CDMA sub-carrier power control method

Technical field

The invention belongs to into lower wireless communication technology field, be specifically related to a kind of mine laneway up MC-CDMA sub-carrier power control method.

Background technology

In a wireless communication system, because electromagnetic wave is in transmitting procedure, transmitted by refraction, reflection and direct projection various ways, can be received by a few paths, this phenomenon is exactly multipath effect.The electromagnetic wave ray phase place that these different paths arrive is inconsistent and have time variation, causes Received signal strength to be fading condition, is multipath fading, and this decline relies on that to increase transmitting power be indelible.Compared to terrestrial wireless channel, the decline of mine laneway radio channel multi-path is more serious, thus have impact on the performance of Underground Wireless Communication System.

The effective anti-multipath fading of multicarrier (MultiCarrier, MC) modulated energy.And code division multiple access (CodeDivisionMultipleAccess, CDMA) technology has, and antijamming capability is strong, the error rate is low and the outstanding advantages of anti-multipath jamming and multipath delay spread.The frequency resource of mine laneway is open, with one of mine laneway wireless communication infrastructure modulation technique that MC-CDMA (MultipleCarrier-CodeDivisionMultipleAccess, the MC-CDMA) technology of multi-transceiver technology fusion CDMA technology is desirable.Under the condition of underground coal mine wireless transmission channel and banded restricted clearance structure, adopt MC-CDMA wireless transmission in the uplink, by making full use of the open frequency resource of mine laneway, overcome the adverse effect that multipath fading causes mine laneway radio communication, efficiently synthetically make use of the various resources such as the space of Mine Communication system, time and frequency, the wireless coverage performance of Underground Wireless Communication System, capacity and speed etc. are significantly improved.

Meanwhile, collaboration diversity utilizes the broadcast characteristic of wireless channel, mutually to be cooperated acquisition uplink transmit diversity by multiple mobile subscriber, effectively can resist radio channel multi-path decline, improve data rate.Mine laneway space is limited banded space, is suitable for very much the communication adopting cooperation multi-hop.Find the good cooperative partner of channel conditions between and base station by the user poor for channel conditions between base station, channel capacity and the bit error rate performance of channel conditions poor user can be significantly improved.The poor place of channel conditions would not be moved to because of user like this, and cause the generation of the situations such as the decay of the channel capacity between base station and user is excessive, the very poor even communication disruption of communication quality.The mode of collaboration diversity mainly contains amplification forwarding (AmplifyandForward, AF), decoding forwards (DecodeandForward, DF) and coding cooperative (CodedCooperation, CC) three kinds of modes.Amplification forwarding and decoding forward the information bit just repeated received by forwarding, and efficiency is lower.And coding cooperative is code word is divided into two parts in itself, each part is transmitted by one of cooperative partner, not only obtains coding gain, but also can between cooperative partner allocated channel coded identification very neatly, code efficiency is very high.

Time frequency coding cooperation MC-CDMA wireless transmission scheme is adopted in mine laneway up link, both the open frequency resource of mine laneway can have been made full use of to overcome multipath fading seriously to the adverse effect that mine laneway radio communication causes, the good cooperative partner of channel conditions between one and base station can be found by the user poor for channel conditions between base station again, significantly improve channel capacity and the bit error rate performance of channel conditions poor user.

The correlation of mine laneway MC-CDMA adjacent sub-carrier is larger, for mine laneway MC-CDMA spread spectrum branch distributes adjacent subcarrier, the quality of mine laneway MC-CDMA spread spectrum branch transmission can be reduced, affect the performance of mine laneway time frequency coding cooperation MC-CDMA system; Simultaneously, the subcarrier of different mine laneway MC-CDMA user has different relative fading severities, and be the optimum subcarrier Dynamic Assignment of mine laneway time frequency coding cooperation MC-CDMA system looks, not only cost is high, amount of calculation is large, also possibly cannot find closed optimal solution.

In existing MC-CDMA system, available transmitting power is averagely allocated to each subcarrier by transmitting terminal.Because the fading severity of each subcarrier of user is different, the mean allocation of transmitting power can cause transmitting power to consume excessively on the poor subcarrier of channel conditions, reduces channel capacity and the performance of BER of system.For improving the utilance of MC-CDMA system emission power, several subcarriers that channel gain can be utilized to be greater than threshold value transmit, and carry out Maximal ratio combiner (MaximalRatioCombining, MRC) at receiving terminal.But, adopt the program, when the channel gain of all subcarriers is all less than threshold value, can causes transmitting and interrupt.The subcarrier utilizing channel gain maximum carries out transmitting, and can sacrifice MC-CDMA system frequency diversity gain while raising transmitting power utilance.

Summary of the invention

The object of the embodiment of the present invention is to provide a kind of mine laneway up MC-CDMA sub-carrier power control method, by mine laneway up time frequency coding cooperation MC-CDMA spread spectrum branch subcarrier Cycle arranging and the corresponding signal to noise ratio of each MC-CDMA subcarrier utilizing receiving terminal to feed back to transmitting terminal, for each spread spectrum branch presses channel conditions and preset ratio removal subcarrier, realize control and the transmission of sub-carrier power, ensure that transmitting power can be effective to the good portion subcarriers of channel conditions in each spread spectrum branch, enhance the reliability of mine laneway time frequency coding cooperation MC-CDMA wireless transmitting system communication.

According to an aspect of the present invention, provide a kind of mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method, described method comprises: carry out Cycle arranging to the subcarrier of up time frequency coding cooperation MC-CDMA spread spectrum branch.

In such scheme, described method also comprises: utilize receiving terminal to feed back to signal to noise ratio corresponding to the subcarrier of each time frequency coding cooperation MC-CDMA spread spectrum branch of transmitting terminal, remove the subcarrier on spread spectrum branch according to preset ratio.

In such scheme, the described subcarrier to up time frequency coding cooperation MC-CDMA spread spectrum branch carries out Cycle arranging, comprises further:

The subcarrier of up for each for mine laneway mobile subscriber time frequency coding cooperation MC-CDMA is divided into groups in order, often group has the subcarrier of same number, and the number often organizing subcarrier is identical with the sum of spread spectrum branch, will often organize the sub carries allocation of same sequence number to the spread spectrum branch of same sequence number.

In such scheme, the signal to noise ratio that the described each time frequency coding cooperation MC-CDMA subcarrier utilizing receiving terminal to feed back to transmitting terminal is corresponding, remove the subcarrier on spread spectrum branch according to preset ratio, comprise further:

To each MC-CDMA mobile subscriber of mine laneway, signal to noise ratio corresponding to each MC-CDMA subcarrier of transmitting terminal is fed back to according to sorting from small to large to receiving terminal, the total number of subcarrier that preset ratio Rd is corresponding with each spread spectrum branch is multiplied, result of product is rounded downwards and is designated as N, according to signal to noise ratio order from small to large remove with the 1st to N number of signal to noise ratio corresponding the 1st to N number of subcarrier, wherein, 0≤Rd≤1;

To each spread spectrum branch corresponding be multiplied by spreading code after, the subcarrier of each time frequency coding cooperation MC-CDMA spread spectrum branch is multiplied by subcarrier validity flag symbol b respectively _p,g, wherein, b _p,gvalue is 0 or 1, and for representing whether g subcarrier of p spread spectrum branch is removed, 0 for being removed, and 1 for being retained.

In such scheme, described method also comprises:

After base station receives each mobile subscriber's signal of mine laneway, the data-signal of each user that data-signal and first time cycle of each mobile subscriber of mine laneway received second time cycle receive mates, and what determine that user transmits second time cycle is the Part II of cooperative partner time frequency coding or the Part II of self time frequency coding;

By the signal before the convolution decoder of the same mine laneway mobile user data of transmission, carry out waiting the signal of gain to be directly added merging and obtain judgment variables;

The judgment variables obtained carried out and launches corresponding convolution decoder, remove N position frame check sequence and BPSK demodulation, obtaining the stay of two nights of mine laneway mobile subscriber

The mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method of the embodiment of the present invention, by carrying out Cycle arranging to the subcarrier of up time frequency coding cooperation MC-CDMA spread spectrum branch, optimize the sub-carrier wave distribution method of mean allocation transmitting power, for each spread spectrum branch of mine laneway up time frequency coding cooperation MC-CDMA is by fixed intervals allocation of discrete subcarrier, relative to subcarrier continuous dispensing, indivedual spread spectrum branch transmission quality can be avoided on the low side, with the problem of low user's overall channel capacity.Simultaneously, receiving terminal is utilized to feed back to signal to noise ratio corresponding to each time frequency coding cooperation MC-CDMA subcarrier of transmitting terminal, the subcarrier on spread spectrum branch is removed according to preset ratio, realize sub-carrier power controls transfer, thus ensure that transmitting power can be effective to the good portion subcarriers of channel conditions in each spread spectrum branch, can while raising mine laneway MC-CDMA transmitting power utilance, take full advantage of mine laneway time frequency coding cooperation MC-CDMA frequency diversity gain, the reliability enhancing the communication of mine laneway time frequency coding cooperation MC-CDMA wireless transmitting system improves the bit error rate performance of user.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme of the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method schematic flow sheet of the embodiment of the present invention;

Fig. 2 is the mine laneway up time frequency coding cooperation MC-CDMA wireless transmitting system schematic diagram of the embodiment of the present invention;

Fig. 3 is the mine laneway up time frequency coding cooperation MC-CDMA wireless transmitting system transmitter block diagram of the embodiment of the present invention;

Fig. 4 is the mine laneway up time frequency coding cooperation MC-CDMA wireless transmitting system receiver block diagram of the embodiment of the present invention;

Fig. 5 is the possible transmission state model of mine laneway up time frequency coding cooperation MC-CDMA tetra-kinds of the embodiment of the present invention;

Fig. 6 is the mine laneway up time frequency coding cooperation MC-CDMA subcarrier Cycle arranging block diagram of the embodiment of the present invention;

Fig. 7 is the forming process figure of the up time frequency coding cooperation of the mine laneway with the pilot tone MC-CDMA data transmission frames of the embodiment of the present invention;

Fig. 8 is the narrow-band sub-carriers centre frequency of the embodiment of the present invention when being 900MHz mine laneway channel gain is with the spacing change curve of dual-mode antenna;

Fig. 9 be the embodiment of the present invention in mine laneway time frequency coding cooperation MC-CDMA up link, adopt different sub carrier power control algorithm time targeted customer bit error rate contrast schematic diagram.

Embodiment

Those skilled in the art of the present technique are appreciated that unless expressly stated, and singulative used herein " ", " one ", " described " and " being somebody's turn to do " also can comprise plural form.Should be further understood that, the wording used in specification of the present invention " comprises " and refers to there is described feature, integer, step, operation, element and/or assembly, but does not get rid of and exist or add other features one or more, integer, step, operation, element, assembly and/or their group.Should be appreciated that, when we claim element to be " connected " or " coupling " to another element time, it can be directly connected or coupled to other elements, or also can there is intermediary element.In addition, " connection " used herein or " coupling " can comprise wireless connections or couple.Wording "and/or" used herein comprises one or more arbitrary unit listing item be associated and all combinations.

Those skilled in the art of the present technique are appreciated that unless otherwise defined, and all terms used herein (comprising technical term and scientific terminology) have the meaning identical with the general understanding of the those of ordinary skill in field belonging to the present invention.Should also be understood that those terms defined in such as general dictionary should be understood to have the meaning consistent with the meaning in the context of prior art, unless and define as here, can not explain by idealized or too formal implication.

For ease of the understanding to the embodiment of the present invention, be described below in detail embodiments of the present invention, the execution mode described by reference to accompanying drawing is exemplary, only for explaining the present invention, and can not be interpreted as limitation of the present invention.

Mine laneway of the present invention up time frequency coding cooperation MC-CDMA sub-carrier power control method, by mine laneway up time frequency coding cooperation MC-CDMA spread spectrum branch subcarrier Cycle arranging, instead of sub-carrier carries out the mean allocation of transmitting power; Utilize receiving terminal to feed back to the corresponding signal to noise ratio of each MC-CDMA subcarrier of transmitting terminal, for each spread spectrum branch removes some poor subcarriers of channel conditions by a certain percentage, realize sub-carrier power controls transfer.Below in conjunction with drawings and the specific embodiments, the present invention is described in further details.

Fig. 1 is a kind of mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method schematic flow sheet of the embodiment of the present invention.

As shown in Figure 1, a kind of mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method of the present embodiment, comprises the steps:

Step S1, carries out Cycle arranging to the subcarrier of up time frequency coding cooperation MC-CDMA spread spectrum branch.

It should be noted that, the sub-carrier power control method of the present embodiment, is the up time frequency coding cooperation MC-CDMA for mine laneway.

Fig. 2 is mine laneway up time frequency coding cooperation MC-CDMA wireless transmitting system schematic diagram.As shown in Figure 2, mine laneway mostly is banded space, wherein any one mobile subscriber is targeted customer 1, be the poor user of channel conditions under normal circumstances, any one mobile subscriber is in addition collaboration user 2, under normal circumstances the good user of channel conditions, by the cooperation of the poor targeted customer 1 of the good collaboration user of channel conditions 2 pairs of channel conditions, improve the error rate ability of targeted customer, thus improve the communication quality in tunnel.

Fig. 3 is the mine laneway up time frequency coding cooperation MC-CDMA wireless transmitting system transmitter block diagram of the embodiment of the present invention.Fig. 4 is the mine laneway up time frequency coding cooperation MC-CDMA wireless transmitting system receiver block diagram of the embodiment of the present invention.As shown in Figure 3 and Figure 4, in mine laneway, carried out the transmission of signal between described targeted customer, collaboration user, base station by up time frequency coding cooperation MC-CDMA transceiver and receiver, comprise the transmitting and receiving of signal.

Fig. 5 is the possible transmission state model of mine laneway up time frequency coding cooperation MC-CDMA tetra-kinds of the embodiment of the present invention.When between targeted customer 1 and base station, channel conditions is poor, base station is the better cooperative partner collaboration user 2 of channel conditions between its selection one and base station by certain rule.The part 1 of its cooperative partner time-frequency code word received in the 1st time cycle according to the decoding of the success of two users, there is the possible transmission state of four kinds of Fig. 5 display in time frequency coding cooperation transmission.Fig. 5 (a) represents targeted customer 1 and collaboration user 2 decoding success part 1s of its cooperative partner time-frequency code, transmits the part 2 of its cooperative partner time-frequency code at second time slot respectively.Fig. 5 (b) represents that targeted customer 1 and collaboration user 2 all fail the part 1 of its cooperative partner time-frequency code of decoding, can only transmit the part 2 of himself time-frequency code at second time slot.Fig. 5 (c) represents the targeted customer 1 decoding success part 1 of its cooperative partner time-frequency code, in the part 2 of its cooperative partner time-frequency code of the second slot transmission; Collaboration user 2 fails the part 1 of its cooperative partner time-frequency code of decoding, can only transmit the part 2 of himself time-frequency code at second time slot.Fig. 5 (d) represents that targeted customer 1 fails the part 1 of its cooperative partner time-frequency code of decoding, can only transmit the part 2 of himself time-frequency code at second time slot; The collaboration user 2 decoding success part 1 of its cooperative partner time-frequency code, in the part 2 of its cooperative partner time-frequency code of the second slot transmission.

In this step, to the subcarrier of the up time frequency coding cooperation MC-CDMA spread spectrum branch of the targeted customer 1 shown in Fig. 2 and collaboration user 2, all carry out Cycle arranging.

The described subcarrier to up time frequency coding cooperation MC-CDMA spread spectrum branch carries out Cycle arranging, be further: the subcarrier of up for each for mine laneway mobile subscriber time frequency coding cooperation MC-CDMA is divided into groups in order, often group has the subcarrier of same number, and the number often organizing subcarrier is identical with the sum of spread spectrum branch, will often organize the sub carries allocation of same sequence number to the spread spectrum branch of same sequence number.

Fig. 6 is the mine laneway up time frequency coding cooperation MC-CDMA subcarrier Cycle arranging block diagram of the embodiment of the present invention.Fig. 6 (a) gives the user i subcarrier of frequency increments.Fig. 6 (b) gives the packet mode of sub-carrier.Fig. 6 (c) gives the method for salary distribution to subcarrier after grouping.As shown in Figure 6, first to the subcarrier 0 of user i in Fig. 6 (a) ..., subcarrier N _c-1be divided into G group in order, often group has P subcarrier, and as Suo Shi Fig. 6 (b), the 1st group is subcarrier 0 ..., subcarrier P-1; 2nd group is subcarrier P ..., subcarrier 2P-1; G group is subcarrier (G-1) * P ..., subcarrier G*P-1.Have P subcarrier corresponding with every group, have P spread spectrum branch, so, P the subcarrier often organized all carries out Cycle arranging on P spread spectrum branch.Concrete, to the G group subcarrier divided, by each group, the 0th sub carries allocation is to spread spectrum branch 0, and i-th sub carries allocation is to spread spectrum branch I, ..., P-1 sub carries allocation, to spread spectrum branch P-1, like this, just obtains the arbitrary spread spectrum branch p of Fig. 6 (c) and divides to obtain p, P+p, ..., the G such as (G-1) P+p discrete subcarrier, 0≤p≤P-1.

By carrying out Cycle arranging to the subcarrier of up time frequency coding cooperation MC-CDMA spread spectrum branch, optimize the sub-carrier wave distribution method of mean allocation transmitting power, for each spread spectrum branch of mine laneway up time frequency coding cooperation MC-CDMA is by fixed intervals allocation of discrete subcarrier, relative to subcarrier continuous dispensing, can avoid that indivedual spread spectrum branch transmission quality is on the low side, problem with low user's overall channel capacity.

Step S2, utilizes receiving terminal to feed back to signal to noise ratio corresponding to each time frequency coding cooperation MC-CDMA subcarrier of transmitting terminal, removes the subcarrier on spread spectrum branch according to preset ratio.

Have in the mine laneway of I (I > 0) individual user up time frequency coding cooperation MC-CDMA wireless transmission in investigation system, the emission process of arbitrary user i.Mine laneway mobile subscriber upstream transmission time slot is divided into two time cycles.First the information source of user i is divided into symbols after biphase phase shift keying (BPSK) modulation, often group has F bit or code element, the F of an arbitrary symbols symbol is expressed as [ai (1) ... ai (F)], value is+1 or-1.

Fig. 7 is the forming process figure of the up time frequency coding cooperation of the mine laneway with the pilot tone MC-CDMA data transmission frames of the embodiment of the present invention.As shown in Figure 7, the forming process of the up time frequency coding of the mine laneway with pilot tone cooperation MC-CDMA data transmission frames is as follows, and F the symbol often organized forms the packet of time-frequency code Part I through the convolutional encoding that namely cyclic redundancy code inserts N position frame check sequence, code check is Rc successively.The packet of time-frequency code Part II is formed again through time-frequency conversion.Time-frequency code comprises two parts, respectively two time cycle transmission.

Assuming that user i forms the packet of time-frequency code Part I by convolution coding be:

$s_i^1=\[S_1,...,S_{\frac{N_d*P}{2}},S_{\frac{N_d*P}{2}+1},...,S_{N_d*P}\]$ [formula 1]

So, after time-frequency conversion, time-frequency code word can be expressed as:

$C_i=\[s_i^1,s_i^2\]=\left[\begin{array}{c}{S}_1,...,S_{\frac{N_d*P}{2}},S_{\frac{N_d*P}{2}+1},...,S_{Nd*P}\\ S_{\frac{N_d*P}{2}+1},...,S_{Nd*P},S_1,...,S_{\frac{N_d*P}{2}}\end{array}\right]$ [formula 2]

In formula, corresponding time-frequency code code word Part I packet and the Part II packet respectively of the first row and the second row.

For the purpose of simple, the time-frequency code Part I packet be made up of Nd*P code element by user i or Part II packet are designated as [Si1 ..., SiNd*P], value is+1 or-1.Packet is divided into P road independently data flow after the serial to parallel conversion of 1:P, will be sent by P spread spectrum branch respectively.Data flow the copying all through 1:G on each road after serial to parallel conversion, forms the parallel data stream that G road is identical, then carries out frequency domain spread spectrum.

Receiving terminal is utilized to feed back to the corresponding signal to noise ratio of each MC-CDMA subcarrier of user i, for each spread spectrum branch some subcarriers that Rd removal channel conditions is poor in proportion, be specially: to each MC-CDMA mobile subscriber of mine laneway, signal to noise ratio corresponding to each MC-CDMA subcarrier of transmitting terminal is fed back to according to sorting from small to large to receiving terminal, the total number of subcarrier that preset ratio Rd is corresponding with each spread spectrum branch is multiplied, result of product is rounded downwards and is designated as N, according to signal to noise ratio order from small to large remove with the 1st to N number of signal to noise ratio corresponding the 1st to N number of subcarrier, wherein, 0≤Rd≤1.

Then to each spread spectrum branch corresponding be multiplied by spreading code after G channel parallel data grouping be multiplied by respectively subcarrier validity flag symbol b _p,g.B _p,gvalue is 0 or 1, and for representing whether g the subcarrier of spread spectrum branch p is removed, 0 for being removed, and 1 for being retained, here, and 0≤p≤P-1,0≤g≤G-1.The subcarrier validity flag that is multiplied by corresponding to each spread spectrum branch of user i afterwards accords with b _p,grear G channel parallel data grouping is multiplied with rectangular pulse respectively, forms G road parallel baseband analog signal.

The formation G road parallel baseband analog signal corresponding to each spread spectrum branch of user i is multiplied by respectively modulate the signal on corresponding subcarrier, f _gP+prepresent the centre frequency that g the subcarrier of spread spectrum branch p is corresponding.Gone out by user i antenna transmission to after the signal plus on each subcarrier of each spread spectrum branch of user i again.

As can be seen from Fig. 5 (a), user i the 1st time cycle ts=1, transmits the part 1 of self code word the transmitter model that composition graphs 3 provides, final transmits can be expressed as:

$x_i^1=\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\Σ}}\underset{g=0}{\overset{G-1}{\Σ}}{s}_i^1\left(p\right)G_i\left(g\right)b_{p,g}rect\left(t\right)e^{j2{\mathrm{\πf}}_{gP+p}t}$ [formula 3]

As can be seen from Figure 5, user i the 2nd time cycle ts=2, if the part 1 of energy decoding success cooperative partner code word, then transmits the part 2 of cooperative partner code word if can not decoding success, transmit the part 2 of self code word the transmitter model that composition graphs 3 provides, when formula (4) and formula (5) list the part 1 of its cooperative partner time-frequency code word that the successfully decoded and decoding failure of user i received in the 1st time cycle respectively, corresponding transmits

$x_i^2=\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\Σ}}\underset{g=0}{\overset{G-1}{\Σ}}{s}_c^2\left(p\right)G_i\left(g\right)b_{p,g}rect\left(t\right)e^{j2{\mathrm{\πf}}_{gP+p}t}$ [formula 4]

$x_i^2=\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\Σ}}\underset{g=0}{\overset{G-1}{\Σ}}{s}_i^2\left(p\right)G_i\left(g\right)b_{p,g}rect\left(t\right)e^{j2{\mathrm{\πf}}_{gP+p}t}$ [formula 5]

In formula (3)-Shi (5), Ec represents the average transmitting power on each MC-CDMA spread spectrum branch of user; [Gi (0), Gi (1) ..., Gi (G-1)] represent the frequency expansion sequence of user i; Fn=fc+ (n-Nc/2)/T (0≤n≤Nc-1), fc is centre carrier frequency, and Nc is total number of sub-carriers, and T is the cycle of each MC-CDMA symbol, and 1/T is the subcarrier spacing of MC-CDMA symbol.Bp, g value is 0 or 1; For representing whether g the subcarrier of spread spectrum branch p is removed, 0 for being removed, and 1 for being retained, here, and 0≤p≤P-1,0≤g≤G-1; Rect (t) is rectangular pulse:

[formula 6]

Between the cooperative partner user j (1≤j≤I, j ≠ i) of user i and base station or a certain user the corresponding narrow band channel of n-th (0≤n≤Nc-1) subcarrier time become impulse response into:

[formula 7]

Wherein, α n (i, BS), be respectively the amplitude of fading and the random phase of user i and the corresponding narrow band channel of the n-th subcarrier between base station; α n (i, j), the amplitude of fading of the corresponding narrow band channel of the n-th subcarrier and random phase between the cooperative partner user j being respectively user i and a certain user.

So, according to the expression formula that user i in formula (3)-Shi (5) transmits, the Received signal strength transmitted behind mine laneway multipath channel arrival base station of the 1st each user of time cycle (ts=1) can be expressed as:

$\begin{array}{c}{r}_{BS}^1\left(t\right)=w\left(t\right)+\underset{i=1}{\overset{I}{\Σ}}\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\mathrm{\Σ}}}\underset{g=0}{\overset{G-1}{\mathrm{\Σ}}}{\mathrm{\α}}_n^{\left(i,BS\right)}{s}_i^1\left(p\right)G_i\left(g\right)b_{p,g}\\ \×rect\left(t\right)e^{j\left(2{\mathrm{\πf}}_{gP+p}t+{\mathrm{\φ}}_n^{\left(i,BS\right)}\right)}\end{array}$ [formula 8]

The Received signal strength after the cooperative partner user j (1≤j≤I) that mine laneway multipath channel arrives a certain user that transmits of the 1st each user of time cycle (ts=1) can be expressed as:

$\begin{array}{c}{r}_j^1\left(t\right)=w\left(t\right)+\underset{\underset{i\≠j}{i=1}}{\overset{I}{\Σ}}\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\mathrm{\Σ}}}\underset{g=0}{\overset{G-1}{\mathrm{\Σ}}}{\mathrm{\α}}_n^{\left(i,j\right)}{s}_i^1\left(p\right)G_i\left(g\right)b_{p,g}\\ \×rect\left(t\right)e^{j\left(2{\mathrm{\πf}}_{gP+p}t+{\mathrm{\φ}}_n^{\left(i,j\right)}\right)}\end{array}$ [formula 9]

The Received signal strength transmitted behind mine laneway multipath channel arrival base station of the 2nd each user of time cycle (ts=2) can be expressed as:

[formula 10]

Wherein, w (t) is independent identically distributed white Gaussian noise, supposes ideal synchronisation here.

In order to eliminate in spread spectrum branch the noise be removed in the corresponding narrow band channel of subcarrier, at Fig. 4, before the signal on each subcarrier of each for MC-CDMA spread spectrum branch is carried out Maximal ratio combiner, first them and b _p,g(0≤p≤P-1,0≤g≤G-1) is multiplied, and the noise be removed in spread spectrum branch in the corresponding narrow band channel of subcarrier is cleared.

It should be noted that, method of the present invention is applicable to any mine laneway mobile communication system adopting time frequency coding cooperation MC-CDMA transmission plan in up link.

The concrete steps of a kind of mine laneway up time frequency coding cooperation MC-CDMA subcarrier Cycle arranging method of the present embodiment comprise:

Step S201, to user i subcarrier 0 ..., subcarrier Nc-1 is divided into G group in order, and often group has P subcarrier, and the 1st group is subcarrier 0 ..., subcarrier P-1; 2nd group is subcarrier P ..., subcarrier 2P-1; G group is subcarrier (G-1) * P ..., subcarrier G*P-1;

Step S202, to the G group subcarrier divided, by the 0th sub carries allocation in each group to spread spectrum branch 0 ..., P-1 sub carries allocation is to spread spectrum branch P-1, and like this, user i arbitrary spread spectrum branch p divide to obtain p, P+p, ..., the G such as (G-1) P+p discrete subcarrier, 0≤p≤P-1;

Based on mine laneway up time frequency coding cooperation MC-CDMA subcarrier Cycle arranging method, the concrete steps of a kind of mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method comprise:

The formation of mine laneway up time frequency coding cooperation MC-CDMA data transmission frames and transmitting step:

Step S301, arbitrary mine laneway mobile subscriber i information source carries out code element packet through the data flow of ovennodulation, and often group has F code element, the F often an organized code element is expressed as [ai (1) ..., ai (F)], value is+1 or-1; Preferably, to the modulation of user signal source in this step, it is biphase phase shift keying (BPSK) modulation.

Step S302, carries out cyclic redundancy code to each code character and namely inserts N position frame check sequence (FCS);

Step S303, the convolutional encoding that code check is Rc is carried out to the code character inserting FCS, final formation he number is the packet of convolutional encoding frame as mine laneway mobile subscriber time-frequency code Part I of Nd*P=(F+N)/Rc, and Nd is the number of data MC-CDMA symbol in data transmission frames; Time-frequency code in this step, be user i information source data carry out chnnel coding (CRC+ convolution+time-frequency conversion) after data, namely mobile subscriber finally carries out the data before MC-CDMA modulate emission.

Step S304, time-frequency conversion is carried out to the convolutional encoding frame as the packet of mine laneway mobile subscriber time-frequency code Part I, the code word negate being about to be positioned at latter half moves to first half, the code word being positioned at previous section is moved to latter half, as the packet of mine laneway mobile subscriber time-frequency code Part II, the time-frequency code any portion be made up of Nd*P code element is designated as [Si1 ... SiNd*P], value is+1 or-1;

Step S305, to each time-frequency code Part I packet that will transmit or Part II packet [Si1 ..., SiNd*P] carry out the serial to parallel conversion of 1:P, data flow be divided into the independently parallel grouping of P road [Si1 ..., SiP; Si (Nd-1) * P+1 ..., SiNd*P] and T, independently launch on P the spread spectrum branch being dispensed on MC-CDMA, [] T represents transpose operation;

Step S306, each road is data flow copying all through 1:G independently, forms the parallel data stream that G road is identical;

Step S307, carry out frequency domain spread spectrum to the spreading code that the G channel parallel data stream length after copying is G, different mine laneway mobile subscribers adopts different spreading codes;

Step S308, receiving terminal is utilized to feed back to the corresponding signal to noise ratio of each MC-CDMA subcarrier of user i, signal to noise ratio corresponding to each MC-CDMA subcarrier of transmitting terminal is fed back to according to sorting from small to large to receiving terminal, the total number of subcarrier that preset ratio Rd is corresponding with each spread spectrum branch is multiplied, result of product is rounded downwards and is designated as N, according to signal to noise ratio order from small to large remove with the 1st to N number of signal to noise ratio corresponding the 1st to N number of subcarrier, wherein, 0≤Rd≤1; Each spread spectrum branch residue NU effectively subcarrier, NU is the smallest positive integral being not less than G*Rd; In this step, Rd represents removal ratio, arranges the value of Rd according to actual needs, and each spread spectrum branch total number of sub-carriers G is multiplied with removal ratio Rd, i.e. the value of NU, for being not less than the smallest positive integral of G*Rd.

What each spread spectrum branch was corresponding is multiplied by spreading code, the data flow that G road is parallel, and corresponding spreading code is multiplied by each road respectively, and the length of spreading code is G, and value is+1 or-1, and the spreading code of each user is mutually orthogonal.Then subcarrier validity flag symbol bp, g, bp, g value is multiplied by the grouping of G channel parallel data is respectively 0 or 1, and for representing whether g the subcarrier of spread spectrum branch p is removed, 0 for being removed, and 1 for being retained, here, and 0≤p≤P-1,0≤g≤G-1;

Step S309, to each spread spectrum branch of user i corresponding be multiplied by subcarrier validity flag symbol bp, g after the grouping of G channel parallel data be multiplied with rectangular pulse respectively, form G road parallel baseband analog signal;

Step S310, the formation G road parallel baseband analog signal corresponding to each spread spectrum branch of user i is multiplied by respectively modulate the signal on corresponding subcarrier, fgP+p represents the centre frequency that g the subcarrier of spread spectrum branch p is corresponding.Gone out by user i antenna transmission to after the signal plus on each subcarrier of each spread spectrum branch of user i again.

User i the 1st time cycle ts=1, transmits the part 1 of self code word final transmits can be expressed as: $x_i^1=\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\Σ}}\underset{g=0}{\overset{G-1}{\Σ}}{s}_i^1\left(p\right)G_i\left(g\right)b_{p,g}rect\left(t\right)e^{j2{\mathrm{\πf}}_{gP+p}t}$

User i the 2nd time cycle ts=2, if the part 1 of energy decoding success cooperative partner code word, then transmits the part 2 of cooperative partner code word if can not decoding success, transmit the part 2 of self code word during the part 1 of its cooperative partner time-frequency code word that the successfully decoded and decoding failure of user i received in the 1st time cycle, corresponding transmits can be expressed as:

$x_i^2=\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\Σ}}\underset{g=0}{\overset{G-1}{\Σ}}{s}_c^2\left(p\right)G_i\left(g\right)b_{p,g}rect\left(t\right)e^{j2{\mathrm{\πf}}_{gP+p}t}$

$x_i^2=\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\Σ}}\underset{g=0}{\overset{G-1}{\Σ}}{s}_i^2\left(p\right)G_i\left(g\right)b_{p,g}rect\left(t\right)e^{j2{\mathrm{\πf}}_{gP+p}t}$

Wherein, Ec represents the average transmitting power on each MC-CDMA spread spectrum branch of user, [Gi (0), Gi (1), ..., Gi (G-1)] represent the frequency expansion sequence of user i, fn=fc+ (n-Nc/2)/T (0≤n≤Nc-1), fc is centre carrier frequency, Nc is total number of sub-carriers, T is the cycle of each MC-CDMA symbol, 1/T is the subcarrier spacing of MC-CDMA symbol, bp, g value is 0 or 1, for representing whether g the subcarrier of spread spectrum branch p is removed, 0 for being removed, 1 for being retained, here, 0≤p≤P-1, 0≤g≤G-1, rect (t) is rectangular pulse:

The reception of mine laneway up time frequency coding cooperation MC-CDMA data transmission frames, specifically comprises:

Step S401, the cooperative partner user j (1≤j≤I) of base station or a certain user receives the transmitting of each user with white Gaussian noise;

The Received signal strength transmitted behind mine laneway multipath channel arrival base station of the 1st each user of time cycle (ts=1) can be expressed as:

$\begin{array}{c}{r}_{BS}^1\left(t\right)=w\left(t\right)+\underset{i=1}{\overset{I}{\Σ}}\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\mathrm{\Σ}}}\underset{g=0}{\overset{G-1}{\mathrm{\Σ}}}{\mathrm{\α}}_n^{\left(i,BS\right)}{s}_i^1\left(p\right)G_i\left(g\right)b_{p,g}\\ \×rect\left(t\right)e^{j\left(2{\mathrm{\πf}}_{gP+p}t+{\mathrm{\φ}}_n^{\left(i,BS\right)}\right)}\end{array}$

The Received signal strength after the cooperative partner user j (1≤j≤I) that mine laneway multipath channel arrives a certain user that transmits of the 1st each user of time cycle (ts=1) can be expressed as:

$\begin{array}{c}{r}_j^1\left(t\right)=w\left(t\right)+\underset{\underset{i\≠j}{i=1}}{\overset{I}{\Σ}}\sqrt{\frac{E_c}{N_U}}\underset{p=0}{\overset{P-1}{\mathrm{\Σ}}}\underset{g=0}{\overset{G-1}{\mathrm{\Σ}}}{\mathrm{\α}}_n^{\left(i,j\right)}{s}_i^1\left(p\right)G_i\left(g\right)b_{p,g}\\ \×rect\left(t\right)e^{j\left(2{\mathrm{\πf}}_{gP+p}t+{\mathrm{\φ}}_n^{\left(i,j\right)}\right)}\end{array}$

The Received signal strength transmitted behind mine laneway multipath channel arrival base station of the 2nd each user of time cycle (ts=2) can be expressed as:

Wherein, w (t) is independent identically distributed white Gaussian noise, supposes ideal synchronisation here;

Step S402, is multiplied by the received signal respectively recover the signal that P*G subcarrier transmits, obtain P spread spectrum branch each self-corresponding G road parallel baseband analog signal;

Step S403, the G road parallel baseband analog signal corresponding to each spread spectrum branch carries out the matched filtering corresponding with transmitting terminal, carries out base band demodulating, forms the grouping of G channel parallel data;

Step S404, it is that the spreading code of G carries out frequency domain spread spectrum that target information source user length is multiplied by G channel parallel data grouping after the base band demodulating corresponding to each spread spectrum branch, obtains each self-corresponding G channel parallel data of corresponding mine laneway target information source user P spread spectrum branch and divides into groups;

Step S405, subcarrier validity flag symbol bp, the g identical with transmitting terminal are multiplied by the G channel parallel data grouping corresponding to each spread spectrum branch of target information source user i respectively, bp, g value is 0 or 1, for representing whether g the subcarrier of spread spectrum branch p is removed, and 0 for being removed, 1 for being retained, here, 0≤p≤P-1,0≤g≤G-1, with be multiplied by subcarrier validity flag accord with bp, g after signal on subcarrier g corresponding to user i kth group p spread spectrum branch be:

Step S406, the be multiplied by subcarrier validity flag corresponding to each spread spectrum branch of target information source user i accords with bp, signal on G subcarrier after g carries out Maximal ratio combiner, obtain target information source user i altogether on P spread spectrum branch send the decision value of packet, on user i p spread spectrum branch send packet decision value be:

Wherein, α p, g represent the amplitude of the transient attenuation on g the subcarrier that user i subcarrier gP+p and spread spectrum branch p is corresponding;

Step S407, on P spread spectrum branch send packet decision value carry out the P:1 parallel serial conversion corresponding with transmitting terminal, formed serial data stream [Zi0 ..., ZiP-1];

Step S408, carries out serial data stream and launches corresponding convolution decoder, cyclic redundancy check (CRC) remove N position frame check sequence and BPSK demodulation, recovering data-signal to the signal that second time cycle receives, also will carry out before convolution decoder and launch corresponding time-frequency inverse transformation, the code word being about to be positioned at latter half moves back to first half, and the code word being positioned at previous section is moved back to latter half.

Base station, to the final process of the mine laneway received each mobile subscriber signal, specifically comprises the steps:

Step S501, the data-signal of each user that data-signal and first time cycle of each mobile subscriber of mine laneway that second time cycle receives by base station receive mates, and what determine that user transmits second time cycle is the Part II of cooperative partner time frequency coding or the Part II of self time frequency coding;

Step S502, by the signal before the convolution decoder of the same mine laneway mobile user data of transmission, carries out waiting the signal of gain to be directly added merging and obtains judgment variables;

Step S503, is undertaken the judgment variables obtained and launches corresponding convolution decoder, removes N position frame check sequence and BPSK demodulation, obtaining the stay of two nights of mine laneway mobile subscriber

For assessing the performance of the mine laneway proposed up time frequency coding cooperation MC-CDMA sub-carrier power control method, Monte Carlo simulation is carried out to mine laneway mobile subscriber bit error rate, and contrasts with the bit error rate of each subcarrier mean allocation transmitting power of each spread spectrum branch.As shown in Figure 2, suppose that mine laneway cell-wide 2a is 10m, height 2b is 6m, and long is 1200m, the coordinate of base station in the cartesian coordinate system of community, tunnel is (2.5,1.5,0), the coordinate of each mobile subscriber is (2.5,-1.5, z), z is the axial distance of mine laneway mobile subscriber apart from base station, and unit is rice.In emulation, centre carrier frequency fc is taken as 900MHz, and the length G of walsh code is taken as 16, and in community, tunnel, except targeted customer, also random distribution has 15 users, and table 1 gives system emulation parameter.Because each subcarrier centre frequency of mine laneway MC-CDMA system is different, channel gain is also different, therefore adopts transmitting signal to noise ratio statement bit error rate more reasonable and easy.

Table 1

Fig. 8 gives narrow-band sub-carriers centre frequency when being 900MHz, and channel gain is with the spacing situation of change of dual-mode antenna.As seen from Figure 8, when the spacing of dual-mode antenna is 200m, channel conditions is not good, needs to carry out time frequency coding collaboration communication.Thus, might as well get targeted customer apart from base station 200m, namely z coordinate is 200.

Fig. 9 gives with compared with each subcarrier mean allocation transmitting power of each spread spectrum branch, adopts the performance of BER of the sub-carrier power control algolithm targeted customer proposed.As can be seen from Figure 9, in mine laneway time frequency coding cooperation MC-CDMA up link, with compared with each subcarrier mean allocation transmitting power of each spread spectrum branch, adopt the sub-carrier power control algolithm proposed that user's bit error rate performance can be made obviously to be promoted.It can also be seen that from Fig. 9, when removal ratio elects 1/2 as, bit error rate performance is best; Continue to strengthen removal ratio, as 5/8, bit error rate performance can be made on the contrary to decline.This is owing to continuing to strengthen removal ratio, decreasing effective sub-carrier number, to the raising of the corresponding average attenuation of each spread spectrum branch institute reserved subcarrier, has been not enough to make up its reduction to frequency diversity gain.Therefore, when adopting sub-carrier power control algolithm, be not that removal ratio is the bigger the better.When determining removal ratio, need according to the concrete estimation to mine laneway channel, the removal ratio that choose reasonable is suitable.

The mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method of the embodiment of the present invention, by carrying out Cycle arranging to the subcarrier of up time frequency coding cooperation MC-CDMA spread spectrum branch, optimize the sub-carrier wave distribution method of mean allocation transmitting power, for each spread spectrum branch of mine laneway up time frequency coding cooperation MC-CDMA is by fixed intervals allocation of discrete subcarrier, relative to subcarrier continuous dispensing, indivedual spread spectrum branch transmission quality can be avoided on the low side, with the problem of low user's overall channel capacity.Simultaneously, receiving terminal is utilized to feed back to signal to noise ratio corresponding to each time frequency coding cooperation MC-CDMA subcarrier of transmitting terminal, the subcarrier on spread spectrum branch is removed according to preset ratio, realize sub-carrier power controls transfer, thus ensure that transmitting power can be effective to the good portion subcarriers of channel conditions in each spread spectrum branch, can while raising mine laneway MC-CDMA transmitting power utilance, take full advantage of mine laneway time frequency coding cooperation MC-CDMA frequency diversity gain, the reliability enhancing the communication of mine laneway time frequency coding cooperation MC-CDMA wireless transmitting system improves the bit error rate performance of user.

One of ordinary skill in the art will appreciate that: accompanying drawing is the schematic diagram of an embodiment, the module in accompanying drawing or flow process might not be that enforcement the present invention is necessary.

As seen through the above description of the embodiments, those skilled in the art can be well understood to the mode that the present invention can add required general hardware platform by software and realizes.Based on such understanding, technical scheme of the present invention can embody with the form of software product the part that prior art contributes in essence in other words, this computer software product can be stored in storage medium, as ROM/RAM, magnetic disc, CD etc., comprising some instructions in order to make a computer equipment (can be personal computer, server, or the network equipment etc.) perform the method described in some part of each embodiment of the present invention or embodiment.

Each embodiment in this specification all adopts the mode of going forward one by one to describe, between each embodiment identical similar part mutually see, what each embodiment stressed is the difference with other embodiments.Especially, for device or system embodiment, because it is substantially similar to embodiment of the method, so describe fairly simple, relevant part illustrates see the part of embodiment of the method.Apparatus and system embodiment described above is only schematic, the wherein said unit illustrated as separating component or can may not be and physically separates, parts as unit display can be or may not be physical location, namely can be positioned at a place, or also can be distributed in multiple network element.Some or all of module wherein can be selected according to the actual needs to realize the object of the present embodiment scheme.Those of ordinary skill in the art, when not paying creative work, are namely appreciated that and implement.

The above; be only the present invention's preferably embodiment, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims (5)

1. a mine laneway up time frequency coding cooperation MC-CDMA sub-carrier power control method, it is characterized in that, described method comprises: carry out Cycle arranging to the subcarrier of up time frequency coding cooperation MC-CDMA spread spectrum branch.

2. MC-CDMA sub-carrier power control method according to claim 1, it is characterized in that, described method also comprises: utilize receiving terminal to feed back to signal to noise ratio corresponding to the subcarrier of each time frequency coding cooperation MC-CDMA spread spectrum branch of transmitting terminal, remove the subcarrier on spread spectrum branch according to preset ratio.

3. MC-CDMA sub-carrier power control method according to claim 1 and 2, is characterized in that, the described subcarrier to up time frequency coding cooperation MC-CDMA spread spectrum branch carries out Cycle arranging, comprises further:

The subcarrier of up for each for mine laneway mobile subscriber time frequency coding cooperation MC-CDMA is divided into groups in order, often group has the subcarrier of same number, and the number often organizing subcarrier is identical with the sum of spread spectrum branch, will often organize the sub carries allocation of same sequence number to the spread spectrum branch of same sequence number.

4. MC-CDMA sub-carrier power control method according to claim 1 and 2, it is characterized in that, the signal to noise ratio that the described each time frequency coding cooperation MC-CDMA subcarrier utilizing receiving terminal to feed back to transmitting terminal is corresponding, remove the subcarrier on spread spectrum branch according to preset ratio, comprise further:

To each MC-CDMA mobile subscriber of mine laneway, signal to noise ratio corresponding to each MC-CDMA subcarrier of transmitting terminal is fed back to according to sorting from small to large to receiving terminal, the total number of subcarrier that preset ratio Rd is corresponding with each spread spectrum branch is multiplied, result of product is rounded downwards and is designated as N, according to signal to noise ratio order from small to large remove with the 1st to N number of signal to noise ratio corresponding the 1st to N number of subcarrier, wherein, 0≤Rd≤1;

To each spread spectrum branch corresponding be multiplied by spreading code after, the subcarrier of each time frequency coding cooperation MC-CDMA spread spectrum branch is multiplied by subcarrier validity flag symbol b respectively _p,g, wherein, b _p,gvalue is 0 or 1, and for representing whether g subcarrier of p spread spectrum branch is removed, 0 for being removed, and 1 for being retained.

5. MC-CDMA sub-carrier power control method according to claim 4, it is characterized in that, described method also comprises:

After base station receives each mobile subscriber's signal of mine laneway, the data-signal of each user that data-signal and first time cycle of each mobile subscriber of mine laneway received second time cycle receive mates, and what determine that user transmits second time cycle is the Part II of cooperative partner time frequency coding or the Part II of self time frequency coding;

By the signal before the convolution decoder of the same mine laneway mobile user data of transmission, carry out waiting the signal of gain to be directly added merging and obtain judgment variables;

The judgment variables obtained carried out and launches corresponding convolution decoder, remove N position frame check sequence and BPSK demodulation, obtaining the stay of two nights of mine laneway mobile subscriber