CN107425886B - Transmission method before a kind of millimeter wave based on zero-forcing beamforming and relay selection - Google Patents
Transmission method before a kind of millimeter wave based on zero-forcing beamforming and relay selection Download PDFInfo
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- CN107425886B CN107425886B CN201710283900.5A CN201710283900A CN107425886B CN 107425886 B CN107425886 B CN 107425886B CN 201710283900 A CN201710283900 A CN 201710283900A CN 107425886 B CN107425886 B CN 107425886B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/024—Channel estimation channel estimation algorithms
- H04L25/0242—Channel estimation channel estimation algorithms using matrix methods
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0408—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more beams, i.e. beam diversity
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/155—Ground-based stations
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
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Abstract
The invention discloses transmission methods before a kind of millimeter wave based on zero-forcing beamforming and relay selection, comprising: by obtaining pilot signal, obtains the channel matrix and initial transmission rate between different nodes；According to the channel gain between RRH and relay, for the corresponding building relay preference list of RRH and relay and RRH preference list, for so that the better relay and RRH of channel condition priority in preference list is higher；Relay is matched with RRH using preference list；According to matching result, the transmission rate of repeated link is calculated, and judges whether corresponding repeated link is active link；If Link down, remove the link and match again, until link is all effective；Wave beam formed matrix is obtained using zero-forcing beamforming technology, and is carried out data transmission based on wave beam formed matrix.Transmission method can provide reliable and stable data transmission, improve the overall performance of network under super-intensive deployment scenario before the millimeter wave based on zero-forcing beamforming and relay selection.
Description
Technical field
The present invention relates to fields of communication technology, particularly relate to a kind of millimeter wave based on zero-forcing beamforming and relay selection
Preceding transmission method.
Background technique
With the continuous development of mobile communication technology, various multimedia services come into being, and cause the quick-fried of data traffic
Fried formula increases.In order to meet the needs of people are to mobile data, the deployment of extensive lightweight base station is further intensive.Cloud wirelessly connects
Enter the flexible and efficient control that the appearance of network (CloudRAN) realizes cloud to extensive base station, gives full play to dense deployment band
The network capacity come increases.Cloud technology is introduced into wireless access network, resource centralization, virtualization of function, service are brought
The resilient infrastructure of automation.However since extensive RRU (Radio Remote Unit) node needs directly proportional forward pass chain
Road, so huge forward pass expense can be generated.Therefore, CloudRAN is badly in need of carrying out the research and innovation of wireless penetration forward pass.
As the densification degree of base station deployment increases, so that operator deployment cost is continuously increased with operation cost, into
One step exacerbates the burden of operator, and carrying out outdoor communication using millimeter wave can be in the case where guaranteeing user rate demand
Lower deployment cost and operation cost are substantially reduced, is the key technology for pushing the communications industry further to develop.Millimeter wave has frequency band
It is resourceful, the advantages that high directivity.Its millimetre-sized wavelength is also advantageous to the deployment of large-scale antenna array, and advises greatly
The application of mould antenna technology (MassiveMIMO) further improves the transmission rate of network, reduces propagation delay time.Based on milli
The wireless forward pass of VHF band has flexible transmittability, supports superelevation rate data stream transmitting, is capable of providing changeable future
The Delay Guarantee of topological structure and differentiation becomes CloudRAN forward pass and innovates technologies.However based on being taught skill before millimeter wave
There is also problems and challenge for art.Such as: millimeter wave can seriously affect wave beam due to its transmission characteristic, the appearance of barrier
The reliability of transmission.Forward pass link state is changeable simultaneously, and different moments forward pass link requirements are different, therefore how to comprehensively consider
Each RRU forward pass channel status and its data transfer demands are that non line of sight RRU carries out reliable forward pass when barrier occurs
Multi-beam transmission is one of the key problem for currently needing to solve.
Current academia and industry focus mainly on improving millimeter wave under line-of-sight transmission about the research of millimeter wave and transmit
Rate reduces hardware lower deployment cost, and the critical problem about millimeter wave transmission reliability fails to obtain enough attention.Though
Right some scholars propose the scheme solved using relaying for the transmission of millimeter wave non line of sight, but the simple scenario only considered is i.e. single
Relay single user simple scenario, the complicated transmission problem being not particularly suited under super-intensive deployment conditions.Therefore, the present invention is being realized
During inventor's discovery in the prior art the prior art has at least the following problems: under super-intensive deployment scenario, before current cloud access
The efficiency and transmission quality for passing forward pass in network is not high, it is difficult to meet the requirement of transmission quality and stability.
Summary of the invention
In view of this, before it is an object of the invention to propose a kind of millimeter wave based on zero-forcing beamforming and relay selection
Transmission method can provide reliable and stable data transmission in cloud Radio Access Network especially under super-intensive deployment scenario,
Improve the overall performance of network.
Based on a kind of above-mentioned purpose millimeter wave forward pass side based on zero-forcing beamforming and relay selection provided by the invention
Method, comprising:
BBU pool obtains the pilot signal that relay and RRH is sent, and obtains corresponding channel matrix, and initialize
The initial rate of all RRH to BBU；Wherein, relay is the relay node disposed in a network, and RRH is Remote Radio Unit,
BBU is baseband processing unit, and BBU pool is baseband pool；
Relay receives the pilot signal of all RRH and is sent to BBU Pool and parsed, and obtains each RRH to each
The channel matrix of relay；
BBU pool respectively corresponds building relay preference according to RRH to the channel gain of each relay, for each RRH
List, for so that the better relay of channel condition priority in preference list is higher；
BBU pool respectively corresponds building RRH preference for each relay according to the channel gain of each relay to RRH
List, for so that the better RRH of channel condition priority in preference list is higher；
Using relay preference list and RRH preference list, the matching of relay and RRH is carried out according to preset algorithm, is used for
So that each relay/RRH is matched with an at most RRH/relay completion respectively；
According to matching result, RRH is calculated by the transmission rate of relay access BBU by corresponding channel matrix, and sentence
Whether the corresponding repeated link that breaks is active link；If Link down, removes the link and match again, until making to match
The all active links of obtained link；
The wave beam formed matrix at the end BBU and the end relay is calculated using zero-forcing beamforming technology, and is based on wave beam forming
Matrix carries out data transmission, and the wave beam formed matrix is used for so that BBU is transmitted and matched according to wave beam formed matrix is corresponding
Plan is handed down to the RRH for relaying or being directly accessed accordingly and carries out data transmission.
Optionally, described to judge that the step of whether corresponding repeated link is active link includes:
Be calculated repeated link correspond to the transmission rate of RRH to relay, the transmission rate of relay to BBU pool with
And the corresponding RRH of direct link directly arrives the transmission rate of BBU pool；
Choose in repeated link that lower basal rate as repeated link in two transmission rates；
Basal rate is multiplied with preset penalty coefficient, obtains the effective speed that repeated link is calculated by optimization；
Judge whether the effective speed is greater than the transmission rate that RRH directly arrives BBU pool, if so, the repeated link has
Effect, otherwise, the repeated link is invalid.
Further, the penalty coefficient is 0.5.
Optionally, when constructing architectures of communication networks, aloft by relay node deployment.
Optionally, when constructing architectures of communication networks, the relay node quantity of deployment is identical as the quantity of RRH.
Optionally, the communication mode of relay node uses DF relaying technique.
Optionally, when constructing architectures of communication networks, the quantity of deployment BBU antenna is more than or equal to the number of corresponding RRH antenna
Amount is used to have enough freedom degrees when so that solving wave beam formed matrix.
Optionally, the step of wave beam formed matrix that the end BBU and the end relay are calculated using zero-forcing beamforming technology
Further include:
Channel information constructs network topology structure to BBU based on the received, and by relay node and RRH node according to distance
Distance numbered accordingly；The number is for so that subsequent match process is orderly stablized；
According to the network topology structure that signal transmits, calculates separately to obtain RRH and be directly connected to the corresponding signal transmission of BBU
Model and signal-to-noise ratio, each RRH correspond to relay node access BBU signal mode and signal-to-noise ratio and each RRH access
The signal mode and signal-to-noise ratio of corresponding relay node；
By corresponding signal-to-noise ratio, calculate separately to obtain that RRH is directly connected to the corresponding transmission rate of BBU and RRH is logical
It crosses relay node and is linked into the corresponding transmission rate of BBU；
It is maximized and rate solution formula for directly transmission and by the way that the building of relay transmission two ways is corresponding respectively
And corresponding constraint condition；Wherein, power consumption constraint when passing through relay transmission is the power consumption constraint individually relayed, and is directly passed
Defeated power consumption constraint is total power consumption constraint；
It solves maximization and rate respectively by zero-forcing beamforming technology, water-filling algorithm and MAXDET, is transmitted
Pre-coding matrix；
BBU and relay is based on transmitting pre-encoding matrix and pre-assigned power carries out data transmission.
Optionally, it is described according to preset algorithm carry out relay and RRH matching the step of include:
All RRH nodes are incorporated as in set T to be matched, all relay nodes are put into set D to be matched；And
The element that set T is arranged is immutable, and the element of set D is variable；
For each of set D node ri, select the highest node R of priority level in corresponding preference listjFor it
With node；Wherein, riFor i-th of relay node in set D, RjFor j-th of RRH node in set T；
Judge current RRH node RjWhether existing history match node, if present node RjThere is no history match nodes
Or present node RjHistory match node ri' in node RjPreference list in priority be lower than relay node ri, then save
Point RjReceive relay node riMatching request, directly update matching matrix and/or, disconnect history match node ri' and by history
Matched node ri' be added do not match in set D, set T deletion of node Rj；
If present node RjHistory match node ri' in node RjPreference list in priority be higher than relay node
ri, then node RjRefuse riThe matching request of node is kept and history match node ri' matching relationship；Node riBy node Rj
It is removed from preference list；If riCorresponding preference list is sky, then D deletion of node ri, otherwise continue matching until matching at
Function.
Judge whether set D is empty set, matches, is matched if so, all RRH nodes are completed with relay node
As a result；Otherwise, continue matching process until D is empty set.
From the above it can be seen that the millimeter wave forward pass provided by the invention based on zero-forcing beamforming and relay selection
Method respectively corresponds building preference list to the mutual channel gain of transit node by RRH node, so that subsequent in reality
It can be realized one-to-one matching when existing data transmission, and then pass through the efficiency and stability of transit node improve data transfer.
By realizing that the cloud Radio Access Network framework of super-intensive deployment not only reduces the cost of operation and deployment using millimeter wave, and
And reduces energy consumption and improve efficiency of transmission.By whether effectively judging repeated link, so that the link tool that matching obtains
There is maximum transmission rate, and then improves the rate of network overall data transmission.Make integral net by force zero figuration technology
Network can obtain optimal system performance under the conditions of rich scatter channel.Therefore, it is herein described based on zero-forcing beamforming with
Transmission method can provide steady in cloud Radio Access Network especially under super-intensive deployment scenario before the millimeter wave of relay selection
Fixed reliable data transmission, improves the overall performance of network.
Detailed description of the invention
Fig. 1 is an implementation of transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection
The flow diagram of example；
Fig. 2 is the applicable scene of transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection
Figure；
Fig. 3 is the data transmission of transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection
Flow chart；
Fig. 4 is RRH in transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection in
After matching flow chart.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with specific embodiment, and reference
Attached drawing, the present invention is described in more detail.
It should be noted that all statements for using " first " and " second " are for differentiation two in the embodiment of the present invention
The non-equal entity of a same names or non-equal parameter, it is seen that " first " " second " only for the convenience of statement, does not answer
It is interpreted as the restriction to the embodiment of the present invention, subsequent embodiment no longer illustrates this one by one.
The present invention relates to the 5th third-generation mobile communication technical fields, and in particular under cloud access framework the millimeter wave of forward pass net without
Line forward pass solution.The program individually sets up relay node using millimeter wave as transmission medium, is improving network transmission
Network transmission reliability has been ensured while benefit.Therefore, the application is intended to the cloud access network architecture for super-intensive deployment,
Wireless forward pass link is constructed using efficient millimeter wave is transmitted, solves how to ensure using relaying technique and beamforming technique
Forward pass network capacity is maximized under conditions of transmission reliability.For multi-user, the complex relay select permeability relayed proposes more
Relay selection method based on matching opinion.A kind of millimeter wave based on zero-forcing beamforming and relay selection of the present invention
BBU in preceding transmission method is communicated between RRH by millimeter wave, when the feelings for occurring stopping at random or channel condition is poor
Condition, RRH may be selected to access BBU by relay to obtain better transmission conditions.
It is transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection shown in referring to Fig.1
One embodiment flow diagram.Transmission method includes: before the millimeter wave based on zero-forcing beamforming and relay selection
Step 101, BBU pool obtains the pilot signal that relay and RRH is sent, and obtains corresponding channel matrix,
And initialize the initial rate of all RRH to BBU；Wherein, relay is the relay node disposed in a network, RRH (Remote
Radio Head) it is Remote Radio Unit, BBU (Building Base band Unit) is baseband processing unit, BBU pool
The baseband pool formed for BBU.The pilot signal is in telecommunication net be measurement or monitoring purpose and the signal that sends, lead to
A channel matrix can be constructed to all nodes by crossing the pilot signal issued.In addition, the application also by by transmission rate into
Row initialization, enables and subsequent judges that selection process under unified standard, improves the accurate of rate calculations for rate
The stability of property and whole system.
Step 102, relay receives the pilot signal of all RRH and is sent to BBU Pool and parsed, and obtains each
Channel matrix of the RRH to each relay；Wherein, pilot frequency information cannot be parsed based on relay, so needing to be sent to BBU
It is parsed in Pool.
Step 103, BBU pool respectively corresponds building for each RRH according to RRH to the channel gain of each relay
Relay preference list (prefer list), for so that the better relay of channel condition priority in preference list is higher；
That is, based on the channel matrix and corresponding channel information that are obtained ahead of time in step 1 or 2, make it possible to be calculated RRH with
Channel gain between relay, so as to construct preference list based on channel gain.Therefore, in the base for considering channel gain
On plinth, the channel condition that can be directed to each RRH node to all relay carries out certain sequence, so that channel condition
Good sequence is preceding, in this way, to carry out matching to RRH and relay be that can match to obtain channel item by preference list subsequent
The optimal matching relationship pair of part.Preferably, others reference factor or influence factor can also be selected according to the actual needs
Go setting preference list.
Step 104, BBU pool respectively corresponds structure for each relay according to the channel gain of each relay to RRH
RRH preference list is built, for so that the better RRH of channel condition priority in preference list is higher；Equally, for relay
To RRH also corresponding building preference list.
Step 105, using relay preference list and RRH preference list, of relay and RRH is carried out according to preset algorithm
Match, is used for so that each relay/RRH is matched at most RRH/relay completion respectively, namely according in preference list
Sequence chooses optimal matching way and relay and RRH is made to realize one-to-one reliable pairing, so that follow-up data passes
It is defeated that there is preferable channel condition.
Step 106, according to matching result, RRH is calculated by corresponding channel matrix and passes through the transmission of relay access BBU
Rate, in this application, in order to obtain preferable transmission rate, also contemplated when being matched RRH node directly transmit with
And transmission rate issues when by relay node indirect communication, those are passed through into the transfer transmission data biography that rate reduces instead
Transmission link excludes, to improve transmission rate on the whole.
Step 107, judge whether matched repeated link is active link；If Link down, removes the link and return
It returns step 105 to match again, until all active links of link for obtaining matching；When Link down, then weight is needed
New matching link, the link instructed is active link.In addition, matched target is so that the transmission speed obtained by matching
Rate is maximum.And when there is matching conflict, it can also be subject to and similarly select principle.
Step 108, the wave beam formed matrix at the end BBU and the end relay is calculated using zero-forcing beamforming technology, and is based on
Wave beam formed matrix carries out data transmission, and the wave beam formed matrix is used for so that BBU is according to the corresponding biography of wave beam formed matrix
It is defeated to be handed down to the corresponding RRH for relaying or being directly accessed with matching plan and carry out data transmission.That is, after completing matching,
The end BBU and the end relay are calculated using zero-forcing beamforming technology (Zero-Farcing Beamforming) in BBU pool
Wave beam formed matrix.The RRH that BBU is handed down to corresponding relaying with matching plan according to scheduled transmission and is directly accessed, network
In all nodes transmit according to schedule, until network topology changes, need to match again selected.
As can be seen from the above embodiments, the millimeter wave forward pass side provided by the invention based on zero-forcing beamforming and relay selection
Method respectively corresponds building preference list to the mutual channel gain of transit node by RRH node, so that subsequent realizing
Data can be realized one-to-one matching when transmitting, and then pass through the efficiency and stability of transit node improve data transfer.It is logical
It crosses and realizes that the cloud Radio Access Network framework of super-intensive deployment not only reduces the cost of operation and deployment using millimeter wave, and
Reduce energy consumption and improves efficiency of transmission.By whether effectively judging repeated link, so that the link that matching obtains has
Maximum transmission rate, and then improve the rate of network overall data transmission.Make overall network by force zero figuration technology
Optimal system performance can be obtained under the conditions of rich scatter channel.Therefore, the herein described zero-forcing beamforming that is based on is in
Transmission method can provide stabilization in cloud Radio Access Network especially under super-intensive deployment scenario before the millimeter wave of selection
Reliable data transmission, improves the overall performance of network.
In addition, it should be noted that, the problem of realizing non line of sight transmission present applicant proposes additional deployment relay node, drop
Low interference of the barrier to RRH.And the step in above-described embodiment is not the actual implementation step of the application program, and it can
Based on actual needs or process adjusting corresponding step sequence, it is only necessary to meet the basic thought of the application method i.e.
It can.
It is described that the step of whether corresponding repeated link is active link judged in some optional embodiments of the application
Include:
Be calculated repeated link correspond to the transmission rate of RRH to relay, the transmission rate of relay to BBU pool with
And the corresponding RRH of direct link directly arrives the transmission rate of BBU pool；Wherein, transmission rate can be by solving mode
It is obtained with signal-to-noise ratio computation.
Choose in repeated link that lower basal rate as repeated link in two transmission rates；
Basal rate is multiplied with preset penalty coefficient, obtains the effective speed R that repeated link is calculated by optimization1；
Preferably, the penalty coefficient is 0.5.
Judge whether the effective speed is greater than the transmission rate R2 that RRH directly arrives BBU pool, if so, the repeated link
Effectively, otherwise, the repeated link is invalid.
In this way, all links for obtaining matching are active link, matching matrix I can also be obtained at this time.And
When being matched, effective speed R1It can be changed accordingly according to different matching results.Matching matrix I is as follows:
In some optional embodiments of the application, when constructing architectures of communication networks, aloft by relay node deployment.
Such as: relay node is disposed on nigh tall building roof or on high mountain.In this way, earth bulging centering can be prevented as far as possible
Transmission after node interferes, and improves the stability and reliability of the relay node transmission data of deployment.
Further, when constructing architectures of communication networks, the relay node quantity of deployment is identical as the quantity of RRH.In this way, making
Peak period is being used even if obtaining, it may have enough relay nodes to carry out the data in RRH the forwarding of data, guarantee net
The stability and reliability of network operation.
Preferably, the communication mode of relay node uses DF relaying technique.In this way, being used by utilizing DF relaying technique
The mode relayed again is first decoded, the increase as directly amplifying bit error rate brought by signal can be effectively avoided.It can sit
To only amplified signal without amplifying noise.Improve the performance of signal transmission.
In some optional embodiments of the application, when constructing architectures of communication networks, the quantity of deployment BBU antenna is greater than
Equal to the quantity of corresponding RRH antenna, it is used to have enough freedom degrees when so that solving wave beam formed matrix.
It is described to calculate the end BBU and the end relay using zero-forcing beamforming technology in some optional embodiments of the application
Wave beam formed matrix the step of further include:
Channel information constructs network topology structure to BBU based on the received, and by relay node and RRH node according to distance
Distance numbered accordingly；The number is for so that subsequent match process is orderly stablized；
According to the network topology structure that signal transmits, calculates separately to obtain RRH and be directly connected to the corresponding signal transmission of BBU
Model and signal-to-noise ratio, each RRH correspond to relay node access BBU signal mode and signal-to-noise ratio and each RRH access
The signal mode and signal-to-noise ratio of corresponding relay node；
By corresponding signal-to-noise ratio, calculate separately to obtain that RRH is directly connected to the corresponding transmission rate of BBU and RRH is logical
It crosses relay node and is linked into the corresponding transmission rate of BBU；
It is maximized and rate solution formula for directly transmission and by the way that the building of relay transmission two ways is corresponding respectively
And corresponding constraint condition；Wherein, power consumption constraint when passing through relay transmission is the power consumption constraint individually relayed, and is directly passed
Defeated power consumption constraint is total power consumption constraint；
It solves maximization and rate respectively by zero-forcing beamforming technology, water-filling algorithm and MAXDET, is transmitted
Pre-coding matrix；
BBU and relay is based on transmitting pre-encoding matrix and pre-assigned power carries out data transmission.
In some optional embodiments of the application, it is described according to preset algorithm carry out relay and RRH matching the step of
Include:
All RRH nodes are incorporated as in set T to be matched, all relay nodes are put into set D to be matched；And
The element that set T is arranged is immutable, and the element of set D is variable；
For each of set D node ri, select the highest node R of priority level in corresponding preference listjFor it
With node；Wherein, riFor i-th of relay node in set D, RjFor j-th of RRH node in set T；
Judge current RRH node RjWhether existing history match node, if present node RjThere is no history match nodes
Or present node RjHistory match node ri' in node RjPreference list in priority be lower than relay node ri, then save
Point RjReceive relay node riMatching request, directly update matching matrix and/or, disconnect history match node ri' and by history
Matched node ri' be added do not match in set D, set D deletion of node ri；
If present node RjHistory match node ri' in node RjPreference list in priority be higher than relay node
ri, then node RjRefuse riThe matching request of node is kept and history match node ri' matching relationship；Node riBy node Rj
It is removed from preference list；If riPreference list is sky, then D deletion of node ri, otherwise continue matching until successful match.
Judge whether set D is empty set, if so, matching is completed in all RRH nodes, obtains matching result；Otherwise, after
Continuous matching process is empty set until D.
The application is deployment and RRH node quantity and antenna in the cloud access forward pass net based on large-scale antenna array
Quantity relaying all the same provides safeguard for the reliable transmission of cloud access forward pass net.For the chain for occurring due to barrier and interrupting
Road, or due to the link of natural cause channel status difference, can be enhanced by relaying, allow the network to meet user's need
It asks.And zero-forcing beamforming technology can eliminate the interference between node under the conditions of rich scatter channel, increase network capacity, because
This, the present invention is formed using zero-forcing beamforming technology and orients narrow wave, realizes the efficient communication of millimeter wave.
It is transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection referring to shown in Fig. 2
Applicable scene figure；Fig. 3 is the number of transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection
According to transmission flow figure；
Transmission method includes: before the millimeter wave based on zero-forcing beamforming and relay selection
Step 1:RRH node and relay node send pilot frequency information, and BBU receives pilot frequency information and to RRH to BBU and relaying
Channel to BBU is estimated.Including obtaining the channel matrix of RRH to BBU and being relayed to the channel matrix of BBU.
Step 2: relay node detects the pilot frequency information that RRH is sent, and sends it to BBU and is parsed, and obtains RRH in
After the channel state information between node.Here channel state information includes channel matrix of the RRH node to relay node.
Step 3:BBU constructs network topological diagram, and relay node and RRH node are numbered according to distance.It is logical
Number is crossed, the matching between subsequent relay node and RRH node is not only contributed to, and is conducive to the implementation of transmission control.
Entire transmission process is divided into two time slots, i.e. timeslot1 and timeslot2 by step 4:BBU.timeslot1
For the broadcast singal issued from BBU, recipient is active relaying or the RRH being directly accessed.Timeslot2 is to be relayed to RRH
Transmission process, relaying communicated with RRH according to matching principle.
Step 5: in timeslot1, BBU sends broadcast singal with the RRH for being directly accessed BBU to active relay, in
After the reception signal of node r are as follows:
Wherein, HrFor the channel matrix for relaying r to BBU, WrFor BBU to relaying r pre-coding matrix,
For interchannel noise.
Wherein, srRepresent the data set that BBU is sent to relaying r；CrFor the mixing of relay node and the RRH for being directly accessed BBU
Set；Represent mean square deviation when noise Normal Distribution.
Step 6: the dry ratio of letter that relaying r can be acquired according to the signal mode in step 5 are as follows:
Step 7: according to signal mode, the mode for being directly accessed the RRH node i of BBU and letter drying can be acquired
It is respectively as follows: than (SINR)
Step 8: according to SINR model, being directly accessed the transmission rate of the RRH of BBU are as follows:
R2,i=log (1+ γi)
Step 9: in timeslot2, G is RRH to the channel state matrix between relay node, and V is relay node to RRH
Transmission matrix.It enablesWherein I is the property shown matrix, represents the match condition between relay node and RRH.
Step 10: actively relaying to the RRH being mutually matched and send signal, RRH node n is received from relay node r's
Signal are as follows:
Step 11: the dry ratio of letter that RRH node n can be acquired according to the mode in step 10 are as follows:
Step 12: if RRH node n accesses BBU by relay node r, the traffic rate of RRH be in two sections of communications compared with
Low rate, and multiplied by caused by penalty coefficient 0.5 alternatively relayed communications as time delay increase, reliability reduce punish
It penalizes, final rate is as follows:
R1,n=0.5*log (1+min { γr,γrn})
Step 13: being all made of maximization in each transmission and rate is that optimization aim solves precoding vector.First
It is as follows that optimization problem can be constructed by taking the transmission of timeslot1 as an example:
subPro1:
max∑log(1+γr)
Wherein, γrFor the SINR value for relaying r, H is channel matrix, and W is pre-coding matrix.First constraint condition guarantees
The transmission power of BBU is within constraint；Second constraint condition ensure that the interference between receiving node is 0
According to zero-forcing beamforming technology it is found that the optimal solution of subPro1 are as follows:
Wherein,For the pseudoinverse of matrix H, γoptIt can be asked by solving following optimization problem
Solution:
subPro2:
max∑log(1+γr)
Wherein PBFor the transmission power consumption constraint of BBU.
Wherein subPro2 can be solved by water-filling algorithm.Optionally, the part of all about wave beam forming is equal in the present invention
It is realized using zero-forcing beamforming technology.
Step 14: in timeslot2, optimization aim is constant, but constraint condition is changed, and power consumption constraint is single
The power consumption constraint of relay rather than total power consumption constraint, framework objective function are as follows:
subPro3:
max∑log(1+γn)
Wherein, first constraint condition and is guaranteed between RRH to guarantee that relaying only sends signal to matched RRH
Interference be 0；In second constraint condition, VrFor the pre-coding matrix for relaying r, PrFor the constraint of the transmission energy consumption of relaying r.
It enablesekIn only k-th element be 1, remaining element is 0.Then
It enables
Then subPro3 can be converted are as follows:
subPro4:
Qn≥0
Wherein, interference is 0 between first constraint condition guarantees RRH；Second constraint condition guarantees that relay node emits function
Rate is less than upper limit value, and third condition is to guarantee that pre-coding matrix is effective.
SubPro4 is the determinant maximization problems of standard, solves subPro4 using MAXDET tool and obtains QnWith vn, finally
It is maximized and rate.
Step 15: timeslot1 and the respective transmission of timeslot2 when matching determining can be obtained by above step
Pre-coding matrix.BBU and relay can be transmitted according to transmission matrix and pre-assigned power.
It is transmission method before the millimeter wave provided by the invention based on zero-forcing beamforming and relay selection referring to shown in Fig. 4
The matching flow chart of middle RRH and relaying.The flow chart is matched based on one-to-one, is specifically included:
All RRH nodes are incorporated as in initialization set T to be matched, all relay nodes are put into be matched
It initializes in set D, set T element is immutable, and D element is variable.Optionally, it is described here it is variable refer to can delete set
In element, and new element can be added in set for set T and D.
RRH arrives the channel gain of each relay node according to it, constructs preference list preferlist1, and channel gain is higher,
Relaying priority in each RRH preference list is higher.
Relay node constructs preference list preferlist2 according to its channel gain to RRH node, and channel gain is got over
Height, RRH priority in each relaying preference list are higher.
For each of set D node riAll select the preferential highest node R in preference listjFor its matching section
Point.
If relay node riIn RRH node RjPreference list in priority be higher than RjCurrent matched node, then
RjReceive riThe matching request of node disconnects its currently matched node ri' matching, and by its current matching node ri' be added
In set D to be matched.
If current hop node riIn RRH node RjPreference list in priority be lower than RjCurrent matching node
ri', then RjNode and ri' node continues to match and refuse riThe matching request of node.riIts preference list of node updates, i.e., will section
Point RjIt is removed from its preference list.
Solve the matching property shown matrix.The matrix all elements of N*N are comfortably turned to 0, according to matching result, more by occurrence
New is 1, other remain 0.
If current hop node riPreference list preferlist2 be sky, then the node matching terminates, and by its from
It is deleted in set D, otherwise return step b continues to match.
If set D is sky, completion is matched, otherwise continues to match.
The transmission rate of repeated link is calculated according to matching result, and is carried out with the non-repeated link rate of same destination node
Compare, judges whether repeated link is effective.That is, comparing rate R of the RRH from relay access BBU1It is directly accessed BBU's with RRH
Rate R2.If R1> R2, then claim from BBU to relay to be again effective to the link of RRH, be otherwise invalid；
Invalid link if it exists, then remove the invalid relaying, and selection is directly accessed BBU, i.e., by the node from collection to be matched
It closes and is removed in 1, remaining node matches again, i.e. the repeatedly operation of above step.
If matching is completed without can remove element in set 1 to be matched.
As can be seen from the above embodiments, the application is transmission method before a kind of millimeter wave based on wave beam forming and relay selection,
The advantages of this method includes at least:
(1) it is transmitted using millimeter wave, the unauthorized resource of frequency range can be efficiently used.Millimeter wave band resource is abundant,
Several Gbps/s even transmission rate of more than ten Gbps/s can be provided to communicate；Millimeter wave directionality is extremely strong, can effectively subtract
Few energy dissipation, improves efficiency of transmission；Millimetre wavelength is extremely short, and grade becomes the hardware realization of large-scale antenna array
It may.And using millimeter wave carry out backhaul transport, operator need not independent deployed fiber, can be effectively reduced operation and deployment
Cost.
(2) using millimeter wave as return link rather than access link can effectively be kept away by node deployment on high building
Regular link down caused by exempting from because of the activity for people or vehicle.
(3) become for channel condition caused by link down caused by the random obstacle being likely to occur and other reasons
Difference, present invention introduces relay selection mechanism, the reliability for providing enough alternate nodes for RRH to guarantee link.
(4) the application uses one-to-one matching way, can disperse the transmission pressure of relay node in cloud access forward pass framework
Power guarantees that network will not have what transmission was limited in peak value.
(5) it is directed to the precoding of large-scale antenna array, using zero-forcing beamforming technology.Linear Precoding calculates
Simply, the system performance of near-optimization can be obtained under the conditions of the rich scatter channel of similar millimeter wave channel.
It should be understood by those ordinary skilled in the art that: the discussion of any of the above embodiment is exemplary only, not
It is intended to imply that the scope of the present disclosure (including claim) is limited to these examples；Under thinking of the invention, above embodiments
Or can also be combined between the technical characteristic in different embodiments, step can be realized with random order, and be existed such as
Many other variations of the upper different aspect of the invention, for simplicity, they are not provided in details.
In addition, to simplify explanation and discussing, and in order not to obscure the invention, it can in provided attached drawing
It is connect with showing or can not show with the well known power ground of integrated circuit (IC) chip and other components.Furthermore, it is possible to
Device is shown in block diagram form, to avoid obscuring the invention, and this has also contemplated following facts, i.e., about this
The details of the embodiment of a little block diagram arrangements be height depend on will implementing platform of the invention (that is, these details should
It is completely within the scope of the understanding of those skilled in the art).Elaborating that detail (for example, circuit) is of the invention to describe
In the case where exemplary embodiment, it will be apparent to those skilled in the art that can be in these no details
In the case where or implement the present invention in the case that these details change.Therefore, these descriptions should be considered as explanation
Property rather than it is restrictive.
Although having been incorporated with specific embodiments of the present invention, invention has been described, according to retouching for front
It states, many replacements of these embodiments, modifications and variations will be apparent for those of ordinary skills.Example
Such as, discussed embodiment can be used in other memory architectures (for example, dynamic ram (DRAM)).
The embodiment of the present invention be intended to cover fall into all such replacements within the broad range of appended claims,
Modifications and variations.Therefore, all within the spirits and principles of the present invention, any omission, modification, equivalent replacement, the improvement made
Deng should all be included in the protection scope of the present invention.
Claims (9)
1. transmission method before a kind of millimeter wave based on zero-forcing beamforming and relay selection characterized by comprising
BBU pool obtains the pilot signal that relay and RRH is sent, and obtains corresponding channel matrix, and initializes all
The initial rate of RRH to BBU；Wherein, relay is the relay node disposed in a network, and RRH is Remote Radio Unit, and BBU is
Baseband processing unit, BBU pool are baseband pool；
Relay receives the pilot signal of all RRH and is sent to BBU Pool and parsed, and obtains each RRH to each relay
Channel matrix；
BBU pool respectively corresponds building relay preference column according to RRH to the channel gain of each relay, for each RRH
Table, for so that the better relay of channel condition priority in preference list is higher；
BBU pool respectively corresponds building RRH preference column for each relay according to the channel gain of each relay to RRH
Table, for so that the better RRH of channel condition priority in preference list is higher；
Using relay preference list and RRH preference list, the matching of relay and RRH is carried out according to preset algorithm, be used for so that
Each relay/RRH is matched with an at most RRH/relay completion respectively；
According to matching result, the transmission rate of BBU, and judgement pair are accessed by relay by corresponding channel matrix calculating RRH
Whether the repeated link answered is active link；If Link down, remove the link and match again, until obtaining matching
The all active links of link；
The wave beam formed matrix at the end BBU and the end relay is calculated using zero-forcing beamforming technology, and is based on wave beam formed matrix
Carry out data transmission, the wave beam formed matrix is for so that BBU is according to the corresponding transmission of wave beam formed matrix and matches plan
The RRH for relaying or being directly accessed accordingly is handed down to carry out data transmission.
2. judging whether corresponding repeated link is active link the method according to claim 1, wherein described
The step of include:
Be calculated repeated link correspond to the transmission rate of RRH to relay, the transmission rate of relay to BBUpool and directly
The corresponding RRH of link directly arrives the transmission rate of BBU pool；
Choose in repeated link that lower basal rate as repeated link in two transmission rates；
Basal rate is multiplied with preset penalty coefficient, obtains the effective speed that repeated link is calculated by optimization；
Judge whether the effective speed is greater than the transmission rate that RRH directly arrives BBU pool, if so, the repeated link is effective,
Otherwise, the repeated link is invalid.
3. according to the method described in claim 2, it is characterized in that, the penalty coefficient is 0.5.
4. the method according to claim 1, wherein relay node is disposed when constructing architectures of communication networks
Aloft.
5. the method according to claim 1, wherein when constructing architectures of communication networks, the relay node of deployment
Quantity is identical as the quantity of RRH.
6. the method according to claim 1, wherein the communication mode of relay node uses DF relaying technique.
7. the method according to claim 1, wherein disposing the number of BBU antenna when constructing architectures of communication networks
Amount is more than or equal to the quantity of corresponding RRH antenna, is used to have enough freedom degrees when so that solving wave beam formed matrix.
8. the method according to claim 1, wherein it is described using zero-forcing beamforming technology calculate the end BBU with
The step of wave beam formed matrix at the end relay further include:
Channel information constructs network topology structure to BBU based on the received, and by relay node and RRH node according to the remote of distance
Closely numbered accordingly；The number is for so that subsequent match process is orderly stablized；
According to the network topology structure that signal transmits, calculates separately to obtain RRH and be directly connected to the corresponding signal mode of BBU
Corresponded to signal-to-noise ratio, each RRH relay node access BBU signal mode and signal-to-noise ratio and each RRH access correspond to
The signal mode and signal-to-noise ratio of relay node；
By corresponding signal-to-noise ratio, calculates separately to obtain RRH and be directly connected to the corresponding transmission rate of BBU and during RRH passes through
The corresponding transmission rate of BBU is linked into after node；
Respectively for directly transmit and by the building of relay transmission two ways it is corresponding maximize with rate solution formula and
Corresponding constraint condition；Wherein, power consumption constraint when passing through relay transmission is the power consumption constraint individually relayed, and directly transmit
Power consumption constraint is total power consumption constraint；
It solves maximization and rate respectively by zero-forcing beamforming technology, water-filling algorithm and MAXDET, obtains transmission and prelist
Code matrix；
BBU and relay is based on transmitting pre-encoding matrix and pre-assigned power carries out data transmission.
9. the method according to claim 1, wherein the matching for carrying out relay and RRH according to preset algorithm
The step of include:
All RRH nodes are incorporated as in set T to be matched, all relay nodes are put into set D to be matched；And it is arranged
The element of set T is immutable, and the element of set D is variable；
For each of set D node ri, select the highest node R of priority level in corresponding preference listjFor its matching section
Point；Wherein, riFor i-th of relay node in set D, RjFor j-th of RRH node in set T；
Judge current RRH node RjWhether existing history match node, if present node RjThere is no history match node or
Present node RjHistory match node ri' in node RjPreference list in priority be lower than relay node ri, then node Rj
Receive relay node riMatching request, directly update matching matrix and/or, disconnect history match node ri' and by history match
Node ri' be added do not match in set D, set D deletion of node ri；
If present node RjHistory match node ri' in node RjPreference list in priority be higher than relay node ri, then
Node RjRefuse riThe matching request of node is kept and history match node ri' matching relationship；Node riBy node RjFrom preference
It is removed in list；If riPreference list is sky, then D deletion of node ri, otherwise continue matching until successful match；
Judge whether set D is empty set, if so, matching is completed in all RRH nodes, obtains matching result；Otherwise, continuation
With process until D is empty set.
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