36 results about "Half duplex relay" patented technology

The invention discloses a power control method embedded into a D2D cellular network and based on a time domain half-duplex relay, and belongs to the technical field of wireless communications. The method relates to a base station B using a point-to-multipoint topological structure cellular network for transmitting, a cellular network receiving terminal C, a D2D transmitting terminal R used as a cellular communication relay and a D2D receiving terminal E; the D2D transmitting terminal is used as a cellular communication relay between the base station B and the receiving terminal C, cellular communication and D2D communication are subjected to combined power control, the full-duplex wireless relay technology is used for achieving orthogonal communication channel frequency spectrum multiplex of the cellular communication and the D2D communication, the minimum data throughout requirement of the cellular communication is met, meanwhile, the throughout of the D2D communication is maximized, hence, the overall performance of the system and the individual performance of users can be considered at the same time, and good balance can be achieved between the system layer and the user layer.

The invention provides an optimal power distribution method in an untrusted relay network. A communication process of a two-hop half-duplex relay network is modelled at first; then, the system security capacity and the energy efficiency are comprehensively considered; on the premise that the total power is ensured to be constant, an optical power distribution factor is solved; therefore, the security energy efficiency of a system is maximum; and the security energy efficiency of the power limited two-hop half-duplex network is increased. According to the optical power distribution method disclosed by the invention, the energy efficiency is considered; the security energy efficiency can be maximized under a total power limiting condition; furthermore, user information is prevented from being cracked by an untrusted relay node as much as possible; a calculation process is simplified through a taylor expansion; and furthermore, the estimation error due to use of the first item in the expansion is not beyond 1%, and can be ignored.

The invention provides an energy distribution method in a two-hop energy collection relay network. In a two-hop half-duplex relay network, in an energy collection process, a source node S and a destination node D transfer a part of energy to an unreliable relay R, in a first time slot of an information transmission process, the S sends useful information to the R, meanwhile the FD sends an interference signal to the R, and in a second time slot of the information transmission process, the R forwards the received signal to the D. The total secure rate of the system is defined, and an optimal energy distribution factor is solved. By adoption of the energy distribution method provided by the invention, the situation of insufficient energy of the relay node can be effectively relieved, the energy distribution factor of the node is iteratively optimized on the premise of ensuring the own energy of the node, and the maximization of the secure rate of the system is achieved.

The invention provides an optimal power allocation method of an untrusted relay network under perfect CSI. The method comprises the following steps: firstly, describing a communication scheme of a two-hop half-duplex relay network, then providing an optimal power allocation scheme, and finally analyzing channel ESR to acquire a reachable safety rate. According to the optimal power allocation method provided by the invention, an optimal power allocation formula in a transmission process is provided to maximize the safety rate, and the ESR under high SNR is further analyzed for evaluating the reachable average safety rate. The approximate optimal power allocation can bring a higher safety rate than equal power allocation.

A method and device are provided for transmitting a digital signal intended for a network having at least four nodes including two transmitters, a relay and a receiver separated from one another by non-orthogonal links, except between the relay and the destination, between which the link is orthogonal, implementing a spatially distributed network code. The method includes: encoding, in each transmitter, supplying a code word for every block of K bits of information; transmitting, in the transmitters, the code word during αN transmission intervals, αε [0,1]; jointly, iteratively detecting / decoding, in the relay, in order to separate interfering streams from the transmitters and to determine, for each stream, a vector representing the K bits of information associated with the code word; jointly encoding, in the relay, the two vectors in order to determine redundancy information, and scheduling the relays to transmit the redundancy information during the (1−α)N following transmission intervals.

The invention provides an optimum power allocation method for an untrusted relay network under bounded CSI (Channel State Information). A communication scheme of a two-hop half-duplex relay network is described and an optimum power allocation scheme is provided; a secrecy rate lower bound is obtained; and a channel ESR (Ergodic Secrecy Rate) is analyzed to obtain a reachable secrecy rate. According to the method, the secrecy rate is maximized through an optimum power allocation formula in a transmission process, the ESR under a high SNR is analyzed, and the reachable average secrecy rate is estimated. The secrecy rate higher than that provided by equal power allocation can be provided by approximate optimum power allocation.

The invention concerns a method to allocate transmission resources in a cell network of cooperative type. Each cell comprises a source, a receiver and optionally a half-duplex relay to relay data transmitted by the source to the receiver. The invention draws advantage from the half-duplex mode of a relay belonging to a cell, by allocating to the source of a neighbouring cell a resource used by this relay during one same transmission timeslot.

The invention relates to the field of wireless communications, and discloses a transmission strategy that fully utilizes double time slots to transmit information, and a multi-resource joint optimization algorithm in a DF (Decode-and-Forward) cooperative multi-relay OFDM (Orthogonal Frequency Division Multiplexing) system under the transmission strategy. The multi-resource joint optimization method comprises the following steps: considering a time-division half-duplex relay, and sending information by a source node on each subcarrier in two time slots; and under a total power constraint condition, performing joint optimization on multi-relay selection and cooperative transmission, time slot freedom, transmission mode, subcarrier pairing and power allocation and other resources, so as to maximize the system transmission rate. The whole system structure is composed of one source node, one target node and K relay nodes, and a selective transmission bandwidth is divided into N subcarriers through an OFDM technology. Compared with the prior art, the optimization algorithm of the invention has a higher information transmission rate and spectral efficiency.

In one aspect of the invention, a method for transmission in a wireless communication system includes selecting by a signal destination one of a source-destination direct transmission, a decode-forward relay transmission, and a compress-forward transmission, responsive to channel gains between a signal source and a relay, between the signal source and the signal destination, and between the relay and the signal destination; informing a selected transmission mode from the selecting step to the signal source and the relay; and operating in the selected transmission mode by the relay.

The invention discloses a half-duplex relay network secure transmission method based on time-division energy collection. The method comprises an information source, a relay and a plurality of sink nodes. All nodes are single antennas. A signal secure transmission process is finished in three time slots. In a first time slot, a relay node converts radio frequency signals sent by the information source into energy through an energy collection technology; in a second time slot, the information source sends useful information to the relay; in a third time slot, the relay broadcasts the received signals to sinks; the energy collected by the first relay is fully used for information forwarding in the third time slot, and the relay works in a half-duplex work mode in the three time slots; and the relay selects one user with the maximum received signal to noise ratio from a plurality of users, as a legal user for service, and the rest unselected users are potential eavesdropping users. According to the method, a cooperation technology and a time-division energy collection technology are combined, the received signal to noise ratio of an eavesdropping channel is reduced, and the security performance of the network is improved.

The invention relates to a method (1) for transmitting a digital signal to a network with at least four nodes comprising two transmitters, a relay and a receiver, separated from one another by non-orthogonal links using a spatially distributed network code. The method includes the following steps: a step (2) in each transmitter, delivering a code word comprising first and second redundancy parts per block of K data bits, whereby the first part can be decoded independently of the second part; a step (3) comprising the transmission in the transmitters of the first part of the code word over aN, a is an element of a set [0,1] transmission intervals; a step (4) comprising combined iterative detection / decoding in the relay, in order to separate the flux originating from the transmitters and to determine, for each flux, a vector representative of the K data bits associated with the code word; a step (5) comprising the combined encoding in the relay of the two vectors in order to determine a redundancy datum; providing an order in the transmitters in order to transmit the second redundancy part over (1 - a )N, a is an element of a set [0, 1] subsequent transmission intervals; and providing an order in the relay in order to transmit (6) the redundancy datum over the (1 - a)N, a is an element of a set [0,1] subsequent transmission intervals.

The invention relates to a power distribution energy acquisition relaying secure communication method based on optimal user selection. The secure transmission process of information is completed by two time slots. In the first time slot, an information source sends useful information to a relay, and a relay node uses the partial power of a received signal to energy acquisition and the reset power to receive the useful information sent by the information source. In the second time slot, the relay broadcasts a signal received in the first time slot to a sink. Energy acquired in the first time slot is fully used for information forwarding of the second time slot. In the method, the cooperative technology and time-division energy acquisition technology are reasonably combined to reduce the received signal-to-noise ratio of the eavesdropping channel, and the security performance of the network is improved, thus ensuring the secure transmission of the information. In the method, the half-duplex relay has the energy acquisition technology, and the received signal-to-noise ratio of the eavesdropping channel is reduced by the cooperation between the relay and the other nodes, so as to ensure the secure transmission of the system.

The invention relates to a virtual full-duplex relay transmission method, which comprises the steps that K source terminals S1, S2, S3,..., SK send signals to a relay R1 in an odd-number time slot (2t-1), a relay R2 performs decoding and re-encoding on signals received in the previous time slot (2t-2) and then forwards the signals to K sink terminals D1, D2,..., DK, the K source terminals S1, S2, S3,..., SK send signals to the relay R2 in an even-number time slot 2t, the relay R1 performs decoding and re-encoding on signals received in the previous time slot (2t-1) and then forwards the signals to the K sink terminals D1, D2,..., DK, the relay R1 and the relay R2 take turns to receive and send signals, the K source terminals S1, S2, S3,..., SK always send signals, the K sink terminals D1, D2,..., DK, always receive signals, thereby realizing the same transmission efficiency with a full-duplex relay method. However, signals are sent and received alternately by using two general half-duplex relay in the method, so that a full-duplex self-interference phenomenon is avoided.

A relaying method performed by a half duplex relay for a telecommunications system. The method includes a reception stage of receiving codewords transmitted by a source, the successive codewords corresponding to B blocks, the first of which can be decoded independently of the other blocks. This stage includes a decoding step of estimating a message from each source based on received codewords, the message being associated with the codewords transmitted by the source. The relay performs an error detection and decision-taking step on messages that are decoded without error. The relay encodes a signal and forwards it to the destination, wherein the signal is representative of only those messages that are decoded without error, such that the relay passes from non-selective reception to selective reception after receiving B1 blocks and switches from the reception stage to the encoding and forwarding stage under control of the error detection and decision stage.

The invention relates to the technical field of communications, and discloses a data transmission method of a transceiver under a two-cell multi-user two-hop network. The data transmission method comprises the steps that in different time slots, a server controls source node groups to conduct data transmitting alternately and adjusts the sequence according to which a half-duplex relay node transmits and receives the data sent by the source node groups according to the differences between the source node groups which transmit the data in different time slots, the relay node obtains local channel state information of itself through channel estimation, and pilot symbols which are subject to pre-coding processing are transmitted while data forwarding is conducted; a target node decodes expected data according to an equivalent channel matrix obtained through estimation. By the adoption of the method, the source node groups, the relay node and the target node do not need to know global channel information, the calculation complexity of the target node can be reduced when the specified degree of freedom is reached by using the local channel information, and better degree-of-freedom performance can be obtained by using more time slot resources.

The invention discloses a bidirectional communication method and device based on relay. According to the technical schemes, a full-duplex base station may, according to the channel parameters acquired between a half-duplex terminal and a full-duplex base station, between a half-duplex terminal and a half-duplex relay, and between a full-duplex base station and a half-duplex relay, select a communication mode from a plurality of configured sets of bidirectional communication modes including direct transmission, relay bidirectional decoding and forwarding transmission, relay downlink decoding and forwarding transmission, and relay uplink decoding and forwarding transmission, for bidirectional communications without the relay and the terminal supporting the full-duplex mode, therefore, reducing the implementation complexity of the relay and the terminal.

A wireless communication system comprises a source node, a destination node, and a plurality of half-duplex relay nodes disposed between the source node and the destination node. The half-duplex relay nodes are configured in two disjoint paths each comprising an equal number of hops from the source node to the destination node. The source node is configured to alternately transmit information via the two disjoint paths in alternating time slots, and the destination node is configured to alternately receive information via the two disjoint paths in alternating time slots.

The invention discloses a relay method and equipment. The relay method is applied to a half-duplex relay and comprises the following steps of: sending the same first symbol vector to relay equipment and receiving equipment in a first time interval; and sending a second symbol vector to the receiving equipment in a second time interval to ensure that the receiving equipment acquires the first symbol vector and the second symbol vector according to a third symbol vector received in the first time interval and a fourth symbol vector received in the second time interval, wherein the third symbol vector comprises the first symbol vector sent by the sending equipment, and the fourth symbol vector comprises the second symbol vector sent by the sending equipment and the first symbol vector forwarded by the relay equipment. Through the technical scheme, full rate transmission of the symbol vectors can be obtained in a half-duplex relay transmission system.

In one aspect of the invention, a method for transmission in a wireless communication system includes selecting by a signal destination one of a source-destination direct transmission, a decode-forward relay transmission, and a compress-forward transmission, responsive to channel gains between a signal source and a relay, between the signal source and the signal destination, and between the relay and the signal destination; informing a selected transmission mode from the selecting step to the signal source and the relay; and operating in the selected transmission mode by the relay.

A relaying method performed by a half duplex relay for a telecommunications system. The method includes a reception stage of receiving codewords transmitted by a source, the successive codewords corresponding to B blocks, the first of which can be decoded independently of the other blocks. This stage includes a decoding step of estimating a message from each source based on received codewords, the message being associated with the codewords transmitted by the source. The relay performs an error detection and decision-taking step on messages that are decoded without error. The relay encodes a signal and forwards it to the destination, wherein the signal is representative of only those messages that are decoded without error, such that the relay passes from non-selective reception to selective reception after receiving B1 blocks and switches from the reception stage to the encoding and forwarding stage under control of the error detection and decision stage.

A relaying method in a telecommunication system having a plurality of sources, a half-duplex relay relay and a recipient. The relay performs a receiving phase of: receiving codewords transmitted by the sources, including estimating for each source a message associated with the codewords transmitted by the source, error detection and decision of error-free decoded messages, which determine the set of sources decoded without error by the relay; a phase of coding and transmitting to the recipient a signal uniquely representative of the selection of messages, such that, after each reception of a block from different sources, the relay receives and decodes a return path from the destination indicating if no or at least one message is decoded without error, these messages determining the set of sources decoded without error. The relay switches from the receiving phase to the coding and transmission phase once a logic rule is valid.

The invention concerns a method to allocate transmission resources in a cell network of cooperative type. Each cell comprises a source, a receiver and optionally a half-duplex relay to relay data transmitted by the source to the receiver. The invention draws advantage from the half-duplex mode of a relay belonging to a cell, by allocating to the source of a neighbouring cell a resource used by this relay during one same transmission timeslot.

The invention relates to a method (1) of transmitting digital signals to a network having at least four nodes comprising two nodes separated from each other by non-orthogonal links using a spatially distributed network code. transmitters, relays, and receivers. The method comprises the following steps: a step (2) in each transmitter for delivering a codeword in blocks of K data bits, the codeword comprising a first and a second redundant part, thereby being compatible with the first The two parts independently decode the first part; step (3), including transmitting the first part of the codeword in the transmitter at αN,α∈[0,1] transmission intervals; step (4), including the combined iterative detection / decoding in the relay to separate the traffic originating from said transmitter and to determine for each traffic a vector representing the K data bits associated with the codeword; step (5) , including combinatorial encoding of the two vectors in the relay in order to determine redundant data; providing an order in the transmitter such that in (1-α)N,α∈[0,1] subsequent transmitting the second redundant portion on transmission intervals; and providing an order in the relay to transmit (6) the redundant data on (1-α)N,α∈[0,1] subsequent transmission intervals .

The invention discloses a virtual full-duplex relay transmission method based on a half-duplex multipath cooperative system, and belongs to the technical field of wireless cooperative communication. The virtual full-duplex relay transmission method based on the half-duplex multipath cooperative system includes the following steps: N relay nodes are added between an information source S and an information sink D to build multi-path relay channels, among all relay nodes capable of successfully decoding a source signal, a relay node with the best channel conditions is selected through a corresponding algorithm to forward the decoded signal, and at the same time, the information source generates a new signal, and transmits the signal to the rest of relay nodes. Thus, in each time slot, the information source can transmit a new signal without waiting for a signal of the last time slot to be relayed and forwarded, thereby realizing virtual all-duplex relay transmission. The virtual full-duplex relay transmission method makes a simulation analysis of interrupt performance, and compared with conventional multi-path relay channels, the method improves the spectrum efficiency of the multi-path relay channels while ensuring a diversity gain, thereby improving performance of a whole system.

The invention discloses a power control method embedded into a D2D cellular network and based on a time domain half-duplex relay, and belongs to the technical field of wireless communications. The method relates to a base station B using a point-to-multipoint topological structure cellular network for transmitting, a cellular network receiving terminal C, a D2D transmitting terminal R used as a cellular communication relay and a D2D receiving terminal E; the D2D transmitting terminal is used as a cellular communication relay between the base station B and the receiving terminal C, cellular communication and D2D communication are subjected to combined power control, the full-duplex wireless relay technology is used for achieving orthogonal communication channel frequency spectrum multiplex of the cellular communication and the D2D communication, the minimum data throughout requirement of the cellular communication is met, meanwhile, the throughout of the D2D communication is maximized, hence, the overall performance of the system and the individual performance of users can be considered at the same time, and good balance can be achieved between the system layer and the user layer.

The invention provides an optimal power allocation method of an untrusted relay network under perfect CSI. The method comprises the following steps: firstly, describing a communication scheme of a two-hop half-duplex relay network, then providing an optimal power allocation scheme, and finally analyzing channel ESR to acquire a reachable safety rate. According to the optimal power allocation method provided by the invention, an optimal power allocation formula in a transmission process is provided to maximize the safety rate, and the ESR under high SNR is further analyzed for evaluating the reachable average safety rate. The approximate optimal power allocation can bring a higher safety rate than equal power allocation.