CN102394733A - Double-base station single-relay multi-user data packet retransmission method based on network coding - Google Patents

Abstract

The invention relates to a double-base station single-relay multi-user data packet retransmission method based on network coding. In the method, two base stations deliver data packets needing retransmission respectively to a relay which sends out the data packets after the relay conducts network coding combination on the data packets according to the receiving state table; therefore, network encoding can be carried out on the retransmitted data packets so as to lead each sending to benefit numerous users and avoid the difficult problems that when the base stations retransmit the data packets the relay and a plurality of users, the data packets needing retransmission of each user are far more than relays and can not conduct coding combination with the data packets needing retransmission of the relays for retransmission as a plurality of link states from the relays to each user and relay have great differences. In the method, the network coding is combined with ARQ (Automatic Repeat-reQuest), the advantage of the network coding can be given full play, the transmission bandwidth can be effectively reduced, and the transmission efficiency of a system can be improved.

Description

The single relaying multi-user's in double-basis station coded data bag repeating method Network Based

Technical field

The present invention relates to a kind of coded data bag repeating method Network Based that is used for the single relaying multi-user in double-basis station, belong to wireless communication technology field.

Background technology

The notion of network code proposed in 2000, and, just obtained extensive concern at once.Network code has merged two technology of route and coding, makes network node both can store forwarding to data, can also carry out encoding process, and reality is verified: use linear network encoding can reach the network multicast capacity.But the benefit of network code is this and more also.Especially because link unreliability and physical layer broadcast characteristic in the wireless network make network code be fit to very much be applied to wireless network.Application network coding can solve traditional route well, stride the insurmountable problem of many technology such as layer design, raising network performance.

Collaborative relaying technique mainly comprises: amplify and transmit, decoding is transmitted and coding cooperation.Wherein " regeneration " relaying that is otherwise known as is transmitted in decoding, and it is to transmit more complicated a kind of collaborative transmission aspect than amplifying.With the descending example that is transmitted as, the via node that works in this pattern carries out decoding processing to the noise interferences that comes from the base station that it receives, to obtain raw information; Then, with the raw information recompile modulation that obtains, send to user side again.

In existing junction network technical research, the most pooled applications of combination of network code and automatic request retransmission (ARQ) is in the diverse network of two-way relaying, multiple access access and multicast.Under these network systems, Applied Physics network code, XOR network code (XOR) or random network code etc., empirical tests can obtain practicing thrift sending time slots, reduce to send number of times, improve efficiency of transmission, increase effects such as throughput of system.Aspect multicast network, existing many researchs concentrate on the single relaying multicast network of single-hop multicast network and single source.Yet the single relaying multi-user's in the double-basis station that relates to for the inventive method network does not but nearly all relate to.

Referring to Fig. 1; Introduce the application scenarios of the inventive method earlier: in illustrated cellular cell, customer group MS1 (MS11, MS12; MS13) be positioned at the coverage cell of base station A; (MS21 MS22) is positioned at the coverage cell of base station B to customer group MS2, and relaying R is positioned at the intersection of two base station A and B institute coverage cell.Customer group MS1 and MS2 need receive the transmission information of these two base station A and B, because of MS1 is positioned at the sub-district of base station A, can directly receive the transmission information of base station A; It is positioned at outside the sub-district of base station B, receive the transmission information of base station B, just must be through the forwarding of relaying R.Likewise, MS2 can directly receive the information of base station B, and receives the information of base station A through relaying R.

Referring to Fig. 2, introduce the modeling to above-mentioned application scenarios: S again ₁And S ₂Represent two base station A and B respectively, R represents relaying Relay,

With

Represent two customer group MS1 and MS2 respectively.Each user will correctly receive S ₁And S ₂M the packet that sends respectively separately.Therefore, whole communication process is divided into two stages: transmission stage and re-transmission stage.The process of wherein sending stage application network coding is following:

S ₁And S ₂The packet that transmits separately is respectively F ₁And F ₂, and can be refined as F ₁={ F ₁₁, F ₁₂..., F _1MAnd F ₂={ F ₂₁, F ₂₂..., F _2M.S ₁To { R, d ₁Transmission packet F _1a, simultaneously, S ₂To { R, d ₂Transmission packet F _2a

If R can correctly receive F _1aAnd F _2a, then to { d ₁, d ₂Transmission network code bag f (F _1a, F _2a), wherein f (g) is the network code function, and natural number subscript a is the packet sequence number, and its maximum is M; Do not receive if R is correct, then R does not do any operation.Then, carry out above-mentioned steps circularly, up to a=M, then the transmission stage finishes, and gets into the re-transmission stage.

The prior art in re-transmission stage has two kinds: the automatic request retransmission scheme (abbreviating the XOR-ARQ scheme as) of automatic request retransmission scheme (abbreviating the ARQ scheme as) and application XOR network code.These two kinds of schemes all are based on the single-hop networks system, carry out repeatedly identical retransmission scheme.

Introduce the retransmission scheme under the single-hop model earlier.Referring to single-hop multicast system shown in Figure 3, base station S is to user { d ₁, d ₂..., d _nSend packet, the packet that each user receives is obeyed the Bei Nuli test, promptly each packet is separate in the accepting state of user side, each packet at user side to set probability and make mistakes and to be dropped, i.e. each user d ₁, d ₂..., d _nThe drop probability of corresponding packet is respectively p ₁, p ₂..., p _n

Referring to Fig. 4, introduce the simplest two users and analyze for example: base station S is to two user d ₁, d ₂Send packet F (k), (k=1,2 ..., M), S_d ₁S and S_d ₂S representes user d respectively ₁And d ₂Two kinds of accepting states of the packet that sends for S; S_d ₁S and S_d ₂S is the vector of 1 row M row, and each element is set or " 0 " respectively, wherein, correct this packet that receives of " 1 " expression, " 0 " expression abandons this packet.Get M=10, after then 10 packets all sent, two users' accepting state table was as shown in the table, and base station S is according to d ₁, d ₂The fixed packet that retransmits of accepting state voting.

Single source two receiving terminal ARQ methods: under the situation of not using network code, only use ARQ, then base station S needs retransmission data packet may F (1), F (3), F (4), F (6), F (7), F (9) successively.From retransmission data packet may F (1) beginning, after S sends F (1), d ₁, d ₂Upgrading the accepting state table according to its reception condition respectively, is not " 1 " if in F (1) respective column any one digit number is arranged in the accepting state table, will continue to retransmit F (1), up to d ₁, d ₂Till all correct the reception, just begin to retransmit next packet F (3).Order retransmits all misdata bags again, till any one digit number in the accepting state table all is " 1 ".

Single source two receiving terminal XOR-ARQ methods: application network coding (XOR-ARQ) technology in retransmission processes can significantly reduce the transmission number of times in re-transmission stage.As above shown in the table, select d earlier ₁, d ₂All receive error data packets and directly retransmit, promptly according to behind the above-mentioned ARQ method re-transmission F (3), d ₁, d ₂Respectively according to its accepting state of reception condition renewal this time table.If the both correctly receives, then F (3) retransmits and finishes, and begins to retransmit next bag; If d ₁, d ₂There is any one correctly not receive, then continues to retransmit F (3), up to d ₁, d ₂All correctly receive F (3), just begin to retransmit next packet.Then, select d ₁, d ₂Two bags of not makeing mistakes simultaneously (like F (1) and F (4), F (6) and F (9)) carry out network code, obtain new coded data packet FNC (1)=F (1) ⊕ F (4), and FNC (2)=F (6) ⊕ F (9) retransmits FNC (1) and FNC (2) again.If d ₁, d ₂All correctly receive FNC (1), then d ₁Can obtain F (4), d through F (4)=FNC (1) ⊕ F (1) decoding ₂Can obtain F (1) through F (1)=FNC (1) ⊕ F (4) decoding.Likewise, if d ₁, d ₂The correct FNC (2) that receives just can obtain corresponding F (6) and F (9).For the F (7) that does not have pairing, just directly retransmit F (7), up to d ₂The correct F (7) that receives retransmits and finishes.So far, d ₁, d ₂All correctly receive all 10 packets, can continue to send other follow-up packets then.

In order to describe easy and not influence the analysis of application scenarios of the present invention, error probability (drop probability) the expression channel quality when adopting each packet to arrive receiving terminal via link.The transmission link of each packet is separate, and among Fig. 4, S is to d ₁Link on the error probability of each bag be p ₁, S is to d ₂Link on the error probability of each bag be p ₂, then the condition of Bei Nuli test is obeyed in the transmission of packet.

Existing retransmission scheme is to be used for scene shown in Figure 1 to single-hop multicast ARQ and XOR-ARQ method; Be exactly in the re-transmission stage; Resolve into three operating procedures among Fig. 3 to scene shown in Figure 1, use two sources, two receiving terminal ARQ methods or two sources, two receiving terminal XOR-ARQ methods respectively in each operating procedure.

The ARQ scheme is a kind of basic scheme that can guarantee reliable transmission, and it utilizes repeatedly to transmit reduces the reception mistake, exchanges reliability to sacrifice the transmission bandwidth resource for as cost.Make transmission bandwidth slightly descend and use the XOR-ARQ scheme, saved transfer resource than the former.Its shortcoming is: when Link State was close, it can play a role well, significantly reduced transmission bandwidth.Yet; In the scene of actual double-basis station single relaying multiple-user network system, the base station to relaying, base station to the user and the different Link States that are relayed between the user all be that difference is huge usually, in this case; XOR-ARQ scheme transmission bandwidth can be drawn close to traditional ARQ scheme, and it is less to gain.Therefore, how to make full use of the gain that network code brings, reduce the transmission bandwidth under the different link circuit condition scenes, just become the new problem of scientific and technical personnel's concern in the industry.

Summary of the invention

In view of this; The purpose of this invention is to provide a kind of coded data bag repeating method Network Based that is used for the single relaying multi-user in double-basis station, the present invention is a kind of automatic request retransmission scheme of improved application XOR network code, i.e. iXOR-ARQ (improved XOR-ARQ) scheme; This method combines network code and ARQ; Give full play to the advantage of network code, effectively reduce transmission bandwidth, improve the efficiency of transmission of system.

In order to reach the foregoing invention purpose; The invention provides a kind of coded data bag repeating method Network Based that is used for the single relaying multi-user in double-basis station; It is characterized in that: two base stations are handed to relaying to the packet that need retransmit separately earlier; After according to the accepting state table these packets being carried out network code combination by relaying, redispatch away; So that the packet to these re-transmissions carries out network code; Make each transmission can both let numerous users be benefited; Avoid because of the state difference great disparity of base station to many links of each user and relaying; Cause the base station when relaying and each user's retransmission data packet may, the packet that each user need retransmit can not carry out the difficult problem that coded combination retransmits with the packet that relaying need retransmit far more than relaying.

Introduce the advantage of the inventive method below: document " Wireless Broadcast Using Network Coding " (is published in " IEEE Transactions on Vehicular Technology " VOL.58; NO.2, FEBRUARY 2009) in the transmission bandwidth (Transmission Bandwidth) of definition be successfully to transmit the desired value of a packet to the required total transmission number of times of all receiving terminals.

If two base station S ₁And S ₂Each is to customer group d ₁And d ₂Send M packet, establish d ₁And d ₂Total transmission number of times is n during all bags of correct reception, and then transmission bandwidth is:

In the formula, the desired value that total degree n is sent in E [n] expression.Under this application scenarios, the transmission bandwidth of the inventive method is:

$\mathrm{\&eta;}=\frac{2M+M{(1-p_1)}^2+2\mathrm{<figure-callout\; id="1"\; label="M\; p"\; filenames="HDA0000105230760000052.png"\; state="\{\{state\}\}">M</figure-callout>}{p}_{}{}_1\frac{1}{1-{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000105230760000052.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}+[M{p}_2-M{p}_1(1-p_2)+M{(1-p_1)}^2{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA0000105230760000031.png,HDA0000105230760000032.png"\; state="\{\{state\}\}">p</figure-callout>}}_2+M[1-{(1-p_1)}^2\left]\right]{\mathrm{\&eta;}}_{\mathrm{BR}}}{2M};$ Wherein,

$=1+\frac{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000105230760000052.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}{1-{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000105230760000052.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}+\frac{1}{2}{(1-p_1)}^2+\frac{1}{2}[1+p_2-p_1(1-p_2)-{(1-p_1)}^2(1-p_2)]{\mathrm{\&eta;}}_{\mathrm{BR}}$

${\mathrm{\&eta;}}_{\mathrm{BR}}=\underset{k=1}{\overset{{\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA0000105230760000052.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+D_2}{\mathrm{\&Sigma;}}}\frac{{(-1)}^{k-1}{\mathrm{<figure-callout\; id="1"\; label="C\; D"\; filenames="HDA0000105230760000052.png"\; state="\{\{state\}\}">C</figure-callout>}}_{D_{}}^{{}_1+D_2}}{1-p_2^k}.$

The inventive method is compared with traditional ARQ scheme and XOR-ARQ scheme, has significantly reduced transmission bandwidth; And, at channel condition not simultaneously, particularly under multilink state condition of different, significantly reduced the average transmission number of times of correct each packet of reception, practiced thrift Internet resources, so the present invention has good popularization and application prospect.

Description of drawings

Fig. 1 is double-basis station single relaying multi-user application scenarios sketch map.

Fig. 2 is the model sketch map of double-basis station single relaying multi-user application scenarios.

Fig. 3 is a single-hop effective multicast model sketch map.

Fig. 4 is two receiving terminal model sketch mapes.

Fig. 5 is the data package retransmission method operating procedure flow chart that the present invention is based on network code.

Fig. 6 is three kinds of scheme transmission bandwidth comparison diagrams in the embodiment of the invention, D ₁=2, D ₂=3.

Fig. 7 is two kinds of scheme coding gain comparison diagrams in the embodiment of the invention, D ₁=2, D ₂=3.

Fig. 8 is three kinds of scheme transmission bandwidth comparison diagrams in the embodiment of the invention, D ₁=8, D ₂=10

Fig. 9 is two kinds of scheme coding gain comparison diagrams in the embodiment of the invention, D ₁=8, D ₂=10.

Figure 10 is three kinds of scheme transmission bandwidth comparison diagrams in the embodiment of the invention, p ₁=0.05, p ₂=0.1, p ₃=0.3.

Figure 11 is two kinds of scheme coding gain comparison diagrams in the embodiment of the invention, p ₁=0.05, p ₂=0.1, p ₃=0.3

Embodiment

For making the object of the invention, technical scheme and advantage clearer, the present invention is made further detailed description below in conjunction with accompanying drawing and embodiment.

For the sake of simplicity, and do not influence the description of the inventive method, do not consider technology such as physical layer modulation here.The present invention is a kind of coded data bag repeating method Network Based that is used for the single relaying multi-user in double-basis station; It is greatly different to the state difference of the many links between the relaying to each user and base station that its basic ideas are based on the base station; Cause the base station when relaying and each user's retransmission data packet may; The packet that each user need retransmit is far away more than relaying desired data bag; After causing using the general network coding to retransmit, the required data of user are surrounded by a large amount of residues, can not carry out the difficult problem that coded combination retransmits with the packet that relaying need retransmit.Therefore, the inventive method is after being handed to the packet that need retransmit separately earlier on the relaying that can make up, according to the accepting state table these packets are carried out the network code combination by relaying by two base stations, to redispatch away; So that make full use of the packet of these re-transmissions of network code reorganization, make each transmission can both let numerous users be benefited.

The application scenarios of the inventive method is identical with Fig. 2, also is two base station S ₁And S ₂Simultaneously to separately customer group d ₁And d ₂Send packet separately, wherein first base station S ₁Customer group d ₁D is arranged ₁Individual separate user, promptly

Second base station S ₂Customer group d ₂D is arranged ₂Individual separate user, promptly

d ₁And d ₂Lay respectively at the other side's cell base station S ₂And S ₁Transmission range beyond, and shared relaying R.S wherein ₁And S ₂The error probability that arrives two link transmission data bags of R all is p ₁, the R branch is clipped to two customer groups

With

Common D ₁+ D ₂The error probability of the transmits data packets of bar link all is p ₂, S ₁And S ₂Divide and be clipped to community user separately

With D ₁+ D ₂The error probability of every link transmission data bag in the bar link all is p ₃, and p ₁≤p ₂≤p ₃

The accepting state table has two kinds, is set up according to the different conditions of the packet that himself receives respectively by relaying and each user respectively: correct if certain packet receives, then its accepting state epiphase is answered the position set; If certain packet receives mistake, then its accepting state epiphase is answered the position reset, and in real time to this information of transmitting terminal feedback.This accepting state table adopts the accepting state of the character representation receiving terminal A of S_AB form to the packet of source end B transmission.

The communication process of the inventive method is with S ₁And S ₂Send M packet respectively as one-period, then S ₁And S ₂The packet that need send in each cycle is respectively F ₁And F ₂, i.e. F ₁={ F ₁(1), F ₁(2) ..., F ₁And F (M) } ₂={ F ₂(1), F ₂(2) ..., F ₂(M) }.Customer group d ₁And d ₂Respectively according to the packet F that receives separately ₁And F ₂With XOR network code packet XOR (F ₁, F ₂) judge whether it correctly receives the packet F that send the other side base station ₂And F ₁, the relevant position set of giving its accepting state table more respectively: " 1 " or " 0 ".

Referring to Fig. 5, introduce three concrete operations steps of the inventive method

Step 1, the transmission stage (this stages operating content is identical with conventional method, and its network code function f (g) of choosing is the XOR network code): two base station S ₁With S ₂Use conventional method to send packet separately respectively, relaying R sends to all users after the packet that receives is carried out the XOR network code.

This step 1 comprises the following operations content:

(11) S ₁And S ₂Respectively to relaying R and the customer group of sub-district { R, d separately ₁And { R, d ₂Transmission packet F ₁(i) and F ₂(i), in the formula, natural number i is the packet sequence number of sending, and its maximum is M.

(12) R and two customer group d ₁And d ₂Upgrade its accepting state table according to reception condition respectively:

R detects its F that receives earlier ₁(i) and F ₂(i) whether all correct, if, then the packet that receives is carried out the XOR network code, and then the packet F after will encoding _R(i)=F ₁(i) ⊕ F ₂(i) send to d ₁And d ₂Otherwise, as long as the F that receives ₁(i) and F ₂(i) have any one packet to make mistakes in, R does not just carry out any operation;

Customer group d ₁With d ₂According to the F that correctly receives separately ₁(i) and F _R(i) and F ₂(i) and F _R(i), carry out separately decoding operation F respectively ₁(i) ⊕ F _R(i) and F ₂(i) ⊕ F _R(i), obtain the packet F of the other side base station ₂(i) and F ₁(i), distinguish corresponding renewal accepting state table separately simultaneously.

(13) S ₁And S ₂Respectively to R and the customer group of sub-district { R, d separately ₁And { R, d ₂Send its sequence number i and increase progressively 1 next packet, promptly return execution in step (12); Up to i=M, i.e. S ₁And S ₂All sent M packet, sent the stage flow process and finish.

Step 2 retransmits the phase I (innovation part of the present invention is that re-transmission is decomposed into two stages, and this is to retransmit the phase I): S ₁With S ₂Respectively to the R and the customer group d of sub-district separately ₁And d ₂Retransmit, make R correctly receive S ₁With S ₂All packets, and know the reception situation of all users to these packets.The content of operation of this step 2 can be decomposed into following two parts:

First is base station S ₁And community user crowd d ₁Content of operation with relaying R execution:

(21) in order to improve R and this community user crowd { R, d ₁The effect of retransmission data packet may, when retransmitting at every turn, S ₁All be according to R and d ₁Accepting state table S_RS ₁And S_d ₁S ₁Select the synthetic retransmission data packet may of misdata package as much as possible, its choice criteria is: all users for R and this sub-district are total to D ₁+ 1 receiving terminal, the misdata bag quantity that belongs to each receiving terminal in the packet of selecting is no more than 1.

(22) S ₁After selected retransmission data packet may carried out the XOR network code, this coded data packet to relaying and this community user crowd { R, d ₁Resend.

(23) each receiving terminal { R, d ₁, be R and all users of this sub-district

Be total to D ₁Whether the coded data packet that+1 receiving terminal detects its reception respectively is correct, if correct the reception just carried out corresponding xor operation, decoding obtains required separately packet, and corresponding renewal accepting state table separately; If R receives mistake, then S ₁Just send this coded data packet once more, after R receives correctly, ability order execution in step (24); At this moment, for each user

The coded data packet that whether correctly receives this re-transmission is not done requirement.

(24) S ₁Retransmit next coded data packet, promptly return execution in step (21), correctly receive S up to R ₁All packet F that send ₁

The operand of second portion is all identical with particular content and first, and both differences are that operating main body makes to be base station S into ₁And customer group d ₁With relaying R:

(2A) in order to improve R and this community user crowd { R, d ₂The effect of retransmission data packet may, when retransmitting at every turn, S ₂All be according to R and d ₂Accepting state table S_RS ₂And S_d ₂S ₂Select the synthetic retransmission data packet may of misdata package as much as possible, its choice criteria is: all users for R and this sub-district are total to D ₂+ 1 receiving terminal, the misdata bag quantity that belongs to each receiving terminal in the misdata bag of selecting is no more than 1.

(2B) S ₂After selected retransmission data packet may carried out the XOR network code, this coded data packet to relaying and this community user crowd { R, d ₂Resend.

(2C) each receiving terminal { R, d ₂, be R and all users of this sub-district

Be total to D ₂Whether the coded data packet that+1 receiving terminal detects its reception respectively correct, if correct the reception just carried out corresponding xor operation, decoding obtain separately required packet, and corresponding renewal accepting state table separately; If R receives mistake, then S ₂Just send this coded data packet once more, after R receives correctly, ability order execution in step (2D); At this moment, for each user The coded data packet that whether correctly receives this re-transmission is not done requirement.

(2D) S ₂Retransmit next coded data packet, promptly return execution in step (2A), correctly receive S up to R ₂All packet F that send ₂

Step 3 retransmits second stage (being innovation part of the present invention): relaying makes all users all correctly receive the packet that send each base station to all user's retransmission data packet may.This step comprises the following operations content:

(31) because of R correctly receives all packets, so R is earlier with first community user crowd d ₁To S ₁And S ₂Accepting state table S_d ₁S ₁And S_d ₁S ₂Merge, obtain d ₁Total accepting state table S_d ₁, i.e. S_d ₁=[S_d ₁S ₁, S_d ₁S ₂]; Likewise, again with second community user crowd d ₂To S ₁, S ₂Accepting state table S_d ₁S ₁And S_d ₂S ₂Merge, obtain d ₂Total accepting state table S_d ₂, i.e. S_d ₂=[S_d ₂S ₁, S_d ₂S ₂]; Then, with S ₁And S ₂The packet F that sends respectively separately ₁And F ₂Merge all packet F that obtain sending, i.e. F=[F ₁, F ₂]; At this moment, R has compiled all packets, wherein, and S_d ₁And S_d ₂Be respectively D ₁Row 2M row and D ₂The matrix of row 2M row, F is the set of all 2M packet;

(32) R is according to d ₁And d ₂New accepting state table S_d ₁And S_d ₂, all select the synthetic retransmission data packet may of misdata package as much as possible when retransmitting at every turn, its choice criteria is: be total to D for two sub-districts ₁+ D ₂Individual all users, the misdata bag quantity that belongs to each user in the misdata bag of selecting is no more than 1;

(33) after R carries out the XOR network code to selected retransmission data packet may, this coded data packet to all user { d of two sub-districts ₁, d ₂Resend.

Whether the coded data packet that each user of (34) two sub-districts

detects its reception respectively is correct; If correct the reception; Just carry out corresponding xor operation; Decoding obtains required separately packet, and corresponding renewal accepting state table separately; If there is a user to receive mistake, then R just sends this coded data packet once more, up to all users that need receive this encoded packets all receive correct after, just order is carried out subsequent step (35);

(35) R retransmits next coded data packet, promptly returns execution in step (32), has all correctly received whole coded data packet up to each user.

The present invention has carried out repeatedly emulation and has implemented test, and experimental result shows: the inventive method is compared with traditional ARQ scheme and XOR-ARQ scheme, and the advantage of its transmission performance is very tangible.

Below with M=8, D ₁=2, D ₂=3 is example, and introduce the situation how relaying is selected and made up the misdata bag according to the accepting state table: each the bar line in the following table is represented the misdata bag that is used for carrying out network code that a group selection goes out.

In order to assess the improvement effect of the inventive method, introduce two notions earlier: transmission bandwidth (Transmission Bandwidth) and network code gain (Network Coding Gain): the former representes that data are bundled into merit is sent to the required total transmission number of times desired value of all receiving terminals.The latter is the ratio that adopts the ARQ scheme merely and adopt both transmission bandwidths of the ARQ scheme that network code is arranged, promptly

$\mathrm{Network\; Coding\; Gain}=\frac{\mathrm{Transmission\; Bandwidth\; of\; ARQ}}{\mathrm{Transmission\; Bandwidth\; of\; XOR}-\mathrm{ARQ}(\mathrm{iXOR}-\mathrm{ARQ})}.$

Referring to Fig. 6, shown D among the figure ₁=2, D ₂=3, M=100, p ₁=0.05, p ₂=0.1, p ₃Change at 0.3 o'clock from 0.1, the inventive method (i.e. iXORARQ among the figure) and the traditional ARQ scheme (ARQ among the figure) and the contrast sketch map of XOR-ARQ scheme (XORARQ among the figure) three's transmission bandwidth curve.Can see obviously that at this moment, no matter be theoretical value or simulation value, the transmission bandwidth of the inventive method is all much smaller than the transmission bandwidth of traditional ARQ scheme and XOR-ARQ scheme.And, along with p ₃Increase, increasing with the gap of the transmission bandwidth of traditional ARQ scheme and XOR-ARQ scheme.

Referring to Fig. 7, the test condition of this figure as above, the inventive method (iXORARQ among the figure) and XOR-ARQ scheme (XORARQ among the figure) are with respect to the big or small comparison diagram of the coding gain of traditional ARQ scheme.It is thus clear that the emulated data of two kinds of schemes all is lower than limit value in theory, the inventive method all is superior to the XOR-ARQ scheme on theoretical value and simulation value, and along with p ₃The increase advantage more obvious.

Then, test increases the situation of receiving terminal quantity: referring to Fig. 8, the figure illustrates D ₁=8, D ₂=10, M=100, p ₁=0.05, p ₂=0.1, p ₃Change at 0.3 o'clock from 0.1, the inventive method (i.e. iXORARQ among the figure) and the traditional ARQ scheme (ARQ among the figure) and the contrast sketch map of XOR-ARQ scheme (XORARQ among the figure) three's transmission bandwidth curve.Can obviously see, at this moment, the transmission bandwidth of the inventive method on theoretical value and simulation value all much smaller than the transmission bandwidth of traditional ARQ scheme and XOR-ARQ scheme.And along with p ₃Increase, increasing with the gap of the transmission bandwidth of traditional ARQ scheme and XOR-ARQ scheme.

Referring to Fig. 9, its test condition as above the figure illustrates the inventive method (i.e. figure in iXORARQ) and traditional XOR-ARQ scheme (XORARQ among the figure) the coding gain size contrast sketch map with respect to traditional ARQ scheme.It is thus clear that the simulation value of these two kinds of schemes all is lower than limit value in theory, the inventive method all is superior to the XOR-ARQ scheme on theoretical and simulation value, and along with p ₃The increase advantage more obvious.

Referring to Figure 10, shown M=100 among the figure, p ₁=0.05, p ₂=0.1, p ₃=0.3; D ₁=D ₂, promptly two users crowd's number of users is identical, all is increased at 20 o'clock from 1, the inventive method (i.e. iXORARQ among the figure) and the traditional ARQ scheme (ARQ among the figure) and the contrast sketch map of XOR-ARQ scheme (XORARQ among the figure) three's transmission bandwidth.Can find out that the transmission bandwidth of the inventive method is on theoretical value and simulation value, all much smaller than the transmission bandwidth of two kinds of conventional methods.And,, increasing with the gap of the transmission bandwidth of two kinds of conventional methods along with the increase of number of users D.

Referring to Figure 11, its test condition is identical with last figure, and this figure is the inventive method (i.e. iXORARQ among the figure) and the size contrast sketch map of XOR-ARQ scheme (XORARQ among the figure) with respect to the coding gain of traditional ARQ scheme.It is thus clear that the simulation value of these two kinds of schemes all is lower than the higher limit of gross data, the inventive method all is superior to the XOR-ARQ scheme on theoretical value and simulation value, and along with the increase advantage of number of users D is more obvious.

Each figure among above-mentioned Figure 10～Figure 11 summarizes, and find: number of users D is big more, and the advantage of the inventive method is obvious more.But simultaneously, the difference of its emulated data and theoretical value is big more.This is that it needs quantity of data packets M also big more, so just can make full use of the combination of packet, reaches the limiting value of gross data because number of users D is big more.And in practical application, M is big more, and the delay of packet is big more, causes service quality to descend, and excessive delay is flagrant for some service.So, should choose suitable M size according to actual needs.

The above is merely preferred embodiment of the present invention, and is in order to restriction the present invention, not all within spirit of the present invention and principle, any modification of being made, is equal to replacement, improvement etc., all should be included within the scope that the present invention protects.

Claims (7)

1. coded data bag repeating method Network Based that is used for the single relaying multi-user in double-basis station; It is characterized in that: two base stations are handed to relaying to the packet that need retransmit separately earlier; After according to the accepting state table these packets being carried out network code combination by relaying, redispatch away; So that the packet to these re-transmissions carries out network code; Make each transmission can both let numerous users be benefited; Avoid because of the state difference great disparity of base station to many links of each user and relaying; Cause the base station when relaying and each user's retransmission data packet may, the packet that each user need retransmit can not carry out the difficult problem that coded combination retransmits with the packet that relaying need retransmit far more than relaying; This method comprises following operating procedure:

(1) the transmission stage: two base station S ₁With S ₂Use conventional method to send packet separately respectively, relaying R sends to all users after the packet that receives is carried out the XOR network code;

(2) retransmit phase I: S ₁With S ₂Respectively to the R and the customer group d of sub-district separately ₁And d ₂Retransmit, make R correctly receive S ₁With S ₂All packets, and know the reception situation of all users to these packets;

(3) retransmit second stage: relaying makes all users all correctly receive the packet that send each base station to all user's retransmission data packet may.

2. method according to claim 1 is characterized in that: the application scenarios of said method is:

Two base station S ₁And S ₂Simultaneously to separately customer group d ₁And d ₂Send packet separately, wherein first base station S ₁Customer group d ₁D is arranged ₁Individual separate user, promptly Second base station S ₂Customer group d ₂D is arranged ₂Individual separate user, promptly

d ₁And d ₂Lay respectively at the other side's cell base station S ₂And S ₁Transmission range beyond, and shared relaying R; S ₁And S ₂The error probability that arrives two link transmission data bags of R all is p ₁, the R branch is clipped to two customer groups

With

Common D ₁+ D ₂The error probability of the transmits data packets of bar link all is p ₂, S ₁And S ₂Divide and be clipped to community user separately

With

D ₁+ D ₂The error probability of every link transmission data bag in the bar link all is p ₃, and p ₁≤p ₂≤p ₃

3. method according to claim 1; It is characterized in that: said accepting state table has two kinds; Set up according to the different conditions of reception packet of himself respectively by relaying and each user respectively: correct if certain packet receives, then its accepting state epiphase is answered the position set; If certain packet receives mistake, then its accepting state epiphase is answered the position reset, and in real time to this information of transmitting terminal feedback; This accepting state table adopts the accepting state of the character representation receiving terminal A of S_AB form to the packet of source end B transmission;

The communication process of said method is with S ₁And S ₂Send M packet respectively as one-period, then S ₁And S ₂The packet that needs to send is respectively F ₁And F ₂, i.e. F ₁={ F ₁(1), F ₁(2) ..., F ₁And F (M) } ₂={ F ₂(1), F ₂(2) ..., F ₂(m) }; Customer group d ₁And d ₂Respectively according to the packet F that receives separately ₁And F ₂With XOR network code packet XOR (F ₁, F ₂) judge whether it correctly receives the packet F that send the other side base station ₂And F ₁, the relevant position set of giving its accepting state table more respectively: " 1 " or " 0 ".

4. method according to claim 1 is characterized in that: said step (1) comprises the following operations content:

(11) S ₁And S ₂Respectively to relaying R and the customer group of sub-district { R, d separately ₁And { R, d ₂Transmission packet F ₁(i) and F ₂(i), in the formula, natural number i is the packet sequence number of sending, and its maximum is M;

(12) R and two customer group d ₁And d ₂Upgrade its accepting state table according to reception condition respectively:

R detects its F that receives earlier ₁(i) and F ₂(i) whether all correct, if, then the packet that receives is carried out the XOR network code, and then the packet F after will encoding _R(i)=F ₁(i) ⊕ F ₂(i) send to d ₁And d ₂Otherwise, as long as the F that receives ₁(i) and F ₂(i) have any one packet to make mistakes in, R does not just carry out any operation;

Customer group d ₁With d ₂According to the F that correctly receives separately ₁(i) and F _R(i) and F ₂(i) and F _R(i), carry out separately decoding operation F respectively ₁(i) ⊕ F _R(i) and F ₂(i) ⊕ F _R(i), obtain the packet F of the other side base station ₂(i) and F ₁(i), distinguish corresponding renewal accepting state table separately simultaneously;

(13) S ₁And S ₂Respectively to R and the customer group of sub-district { R, d separately ₁And { R, d ₂Send its sequence number i and increase progressively 1 next packet, promptly return execution in step (12); Up to i=M, i.e. S ₁And S ₂All sent M packet, sent the stage flow process and finish.

5. method according to claim 1 is characterized in that: in the said step (2), and first base station S ₁And place community user crowd d ₁The content of operation of carrying out with relaying R is described below:

(21) in order to improve R and this community user crowd { R, d ₁The effect of retransmission data packet may, when retransmitting at every turn, S ₁All be according to R and d ₁Accepting state table S_RS ₁And S_d ₁S ₁Select the synthetic retransmission data packet may of misdata package as much as possible, its choice criteria is: all users for R and this sub-district are total to D ₁+ 1 receiving terminal, the misdata bag quantity that belongs to each receiving terminal in the packet of selecting is no more than 1;

(22) S ₁After selected retransmission data packet may carried out the XOR network code, this coded data packet to relaying and this community user crowd { R, d ₁Resend;

(23) each receiving terminal { R, d ₁, be R and all users of this sub-district

Be total to D ₁Whether the coded data packet that+1 receiving terminal detects its reception respectively is correct, if correct the reception just carried out corresponding xor operation, decoding obtains required separately packet, and corresponding renewal accepting state table separately; If R receives mistake, then S ₁Just send this coded data packet once more, after R receives correctly, ability order execution in step (24); At this moment, for each user

The coded data packet that whether correctly receives this re-transmission is not done requirement;

(24) S ₁Retransmit next coded data packet, promptly return execution in step (21), correctly receive S up to R ₁All packet F that send ₁

6. method according to claim 1 is characterized in that: in the said step (2), and second base station S ₂And place community user crowd d ₂The content of operation of carrying out with relaying R is described below:

(2A) in order to improve R and this community user crowd { R, d ₂The effect of retransmission data packet may, when retransmitting at every turn, S ₂All be according to R and d ₂Accepting state table S_RS ₂And S_d ₂S ₂Select the synthetic retransmission data packet may of misdata package as much as possible, its choice criteria is: all users for R and this sub-district are total to D ₂+ 1 receiving terminal, the misdata bag quantity that belongs to each receiving terminal in the misdata bag of selecting is no more than 1;

(2B) S ₂After selected retransmission data packet may carried out the XOR network code, this coded data packet to relaying and this community user crowd { R, d ₂Resend;

(2C) each receiving terminal { R, d ₂, be R and all users of this sub-district

Be total to D ₂Whether the coded data packet that+1 receiving terminal detects its reception respectively correct, if correct the reception just carried out corresponding xor operation, decoding obtain separately required packet, and corresponding renewal accepting state table separately; If R receives mistake, then S ₂Just send this coded data packet once more, after R receives correctly, ability order execution in step (2D); At this moment, for each user

The coded data packet that whether correctly receives this re-transmission is not done requirement.

(2D) S ₂Retransmit next coded data packet, promptly return execution in step (2A), correctly receive S up to R ₂All packet F that send ₂

7. method according to claim 1 is characterized in that: said step (3) comprises the following operations content:

(31) because of R correctly receives all packets, so R is earlier with first community user crowd d ₁To S ₁And S ₂Accepting state table S_d ₁S ₁And S_d ₁S ₂Merge, obtain d ₁Total accepting state table S_d ₁, i.e. S_d ₁=[S_d ₁S ₁, S_d ₁S ₂]; Likewise, again with second community user crowd d ₂To S ₁, S ₂Accepting state table S_d ₂S ₁And S_d ₂S ₂Merge, obtain d ₂Total accepting state table S_d ₂, i.e. S_d ₂=[S_d ₂S ₁, S_d ₂S ₂]; Then, with S ₁And S ₂The packet F that sends respectively separately ₁And F ₂Merge all packet F that obtain sending, i.e. F=[F ₁, F ₂]; At this moment, R has compiled all packets, wherein, and S_d ₁And S_d ₂Be respectively D ₁Row 2M row and D ₂The matrix of row 2M row, F is the set of all 2M packet;

(32) R is according to d ₁And d ₂New accepting state table S_d ₁And S_d ₂, all select the synthetic retransmission data packet may of misdata package as much as possible when retransmitting at every turn, its choice criteria is: be total to D for two sub-districts ₁+ D ₂Individual all users, the misdata bag quantity that belongs to each user in the misdata bag of selecting is no more than 1;

(33) after R carries out the XOR network code to selected retransmission data packet may, this coded data packet to all user { d of two sub-districts ₁, d ₂Resend.

Whether the coded data packet that each user of (34) two sub-districts

detects its reception respectively is correct; If correct the reception; Just carry out corresponding xor operation; Decoding obtains required separately packet, and corresponding renewal accepting state table separately; If there is a user to receive mistake, then R just sends this coded data packet once more, up to all users that need receive this encoded packets all receive correct after, just order is carried out subsequent step (35);

(35) R retransmits next coded data packet, promptly returns execution in step (32), has all correctly received whole coded data packet up to each user.

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