39 results about "Subcarrier pairing" patented technology

A multicarrier communication apparatus capable of reducing an amount of information required for feedback, making a range of transmission power fluctuation small, and achieving rapid convergence on a target transmission power is disclosed. With this apparatus, subcarrier pair determination section (1142) puts a plurality of subcarriers contained in a multicarrier signal into pairs, notifies combining section (106) of information pertaining to the pairs of subcarriers, combines received power of each pair of subcarriers, and outputs combined received power obtained in this manner to command producing section (1146). Target power storage section (1144) stores target power for received power in such a manner that SIR at the subject apparatus becomes a desired SIR. Command producing section (1146) compares combined received power for the pairs of subcarriers and target received power, produces a command indicating a difference in power between these two received powers, and generates a control signal containing the produced command.

The invention provides a method aiming at the overall consideration and complexity of an uplink in a synergetic OFDM (orthogonal frequency division multiplexing) system for the resource allocation in a synergetic OFDM system. The method is characterized in that relays with the number thereof being a positive integer are arranged between a subscriber and a base station and each relay is provided with a plurality of subcarriers with the number being identical with that of the relays. The method comprises the following steps: firstly, the base station selects a relay according to the minimum equivalent signal-to-noise ratios of the subcarriers in each relay, that is, the base station selects the relay with the maximal equivalent signal-to-noise ratio of the subcarriers from the relays with the minimal equivalent signal-to-noise ratio of the subcarriers as the relay node for the subsequent synergetic transmission; then, the selected relay sequences the subcarriers between the subscriber and the selected relay and between the subscriber and the base station sequentially pair the subcarriers, namely, the subcarriers of the relay with high signal-to-noise ratio are used for transmitting the data supposed to be transmitted by the subcarriers of the subscriber with high signal-to-noise ratio; and finally, the base station carries out the water-filling power allocation on each intra-subcarrier according to the equivalent channel gain of each subcarrier pair, and starts the synergetic transmission.

The invention discloses an energy efficient optimization algorithm of a multi-user OFDM relay system. On the premise of satisfying the minimum transmission rate of the system, a strategy that a source still sends data at a TS2 is adopted so as to provide a diversity gain; and a system energy efficiency optimization model containing subcarrier pairing and power allocation is constructed. The model is a typical nonlinear mixed integer programming problem; this kind of problem is generally solved very complexly; by defining an equivalent channel gain, the complex optimization problem is simplified into a quasi convex programming problem; an optimum solution is solved by using a Dinkelbach method, a Hungary algorithm and a sub-gradient algorithm; the computing complexity is greatly reduced; and a simulation result shows that through adoption of the algorithm provided by the invention, under a condition of satisfying the demand of the system for the minimum transmission rate, the energy efficiency of the system is improved; and good global convergence is realized.

The invention discloses a resource allocation method comprehensively considering trunk node selection, subcarrier pairing and power control, which is based on the solution of orthogonal frequency division multiple access relay system resource allocation of a game theory. The trunk nodes divide equivalent channel gain obtained by calculation into quantized intervals, and feed back the serial number of the quantized interval to which the trunk node belongs, thereby ensuring that cooperative node selection can be determined through less bit information interchange. A base station firstly allocates the subcarrier of each trunk node for the second jump, and then the trunk nodes select a user node. Subcarriers of two jumps are matched by using megamerger as the purpose, and the maximum flow and minimum division theory are utilized to determine the transmitted power on corresponding subcarrier when trunk nodes are forwarded. Particularly, a speed utility function based on unit power is established, a price mechanism based on link quality and transmitted power is introduced, and price factors can be adjusted in real time according to different service requirements, thereby realizing the optimized allocation of transmitted power of user nodes on each selected subcarriers.

The invention discloses a resource distribution method and a resource distribution device for a multi-relay orthogonal frequency division multiplexing system. The resource distribution method for the multi-relay orthogonal frequency division multiplexing system comprises the following steps: acquiring actual channel information, and acquiring a resource distribution parameter according to actual channel information-based mathematical optimization problem, wherein the resource distribution parameter comprises at least two of subcarrier power distribution, relay selection and subcarrier pairing, and the mathematical optimization problem is set for the subcarrier power distribution, relay selection and subcarrier pairing on the basis of channel information by utilizing end-to-end transmission rate optimization principle; and transmitting signals according to the resource distribution parameter. The technical scheme optimizes the system performance.

The invention discloses a union resource distributing method of an improved-type multi-user OFDM (orthogonal frequency division multiplexing) DF (decoding forwarding) system, wherein a relay station assist information source with a DF (decoding-forwarding) mechanism communicates with a plurality of users; the union resource distribution of the system is realized through a dual-time-clearance transmission mode, comprising system subcarrier matching, subcarrier pair-user distribution as well as subcarrier power distribution; based on the analysis of channel state information by a pivot control unit, the system working mode switching is realized; and when a certain subcarrier of the system is in the idle mode, an idle subcarrier of an information source second time clearance is allowed to be transmitted additionally. Compared with the traditional OFDM based multi-user relay cooperative system, the method provided by the invention effectively overcomes the defect that a relay subcarrier of the traditional OFDM system can not be fully utilized at the second time clearance and obviously improves the frequency spectrum frequency.

The invention provides a transmitter, a method for the transmitter and a subcarrier pairing method. The method for the transmitter firstly includes that a sequence of coded and interleaved bits is de-multiplexed into a number of bit-streams. Each bit-stream is mapped into a sequence of Quadrature Amplitude Modulation (QAM) symbols, which are grouped into non-overlapping sets of QAM symbols. Unitary transformation is then applied on the QAM symbols to produce groups of complex signals. Finally, the complex signals are dynamically mapped to subcarrier groups based on tone mapping information to improve link performance. The tone mapping information is derived from information associated with each OFDM subcarrier, such as Channel State Information (CSI). The OFDM subcarriers are grouped into subcarrier groups according to the tone mapping information such that the channel quality of each subcarrier group is balanced. The inventive transmitter, the method for the transmitter and the subcarrier pairing method can improve the whole efficiency of the channel link.

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.

The invention discloses a sending method, a receiving method and a device capable of lowering out-of-band radiation, and belongs to the field of communication. The sending method and the receiving method comprise that an orthogonal frequency division multiplexing (OFDM) subcarrier is divided into subcarrier pairs, each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier can be divided at most into one subcarrier pair; two complex weighting coefficients are used for mapping each constellation symbol contained in a to-be-sent data bit stream to two OFDM subcarriers contained in the subcarrier pair corresponding to each constellation symbol, and out-of-band radiation generated by the two OFDM subcarriers is offset; reversed fast Fourier transformation is carried out to the mapped to-be-sent data bit stream, and a cyclic prefix is inserted in the to-be-sent data bit stream to form an OFDM baseband signal which is sent then. The device comprises a dividing module, a mapping module and a modulation module. By means of the sending method, the receiving method and the device, operation complexity can be reduced.

The invention discloses a resource combined distributing method in a bidirectional multi-relay OFDM system. In the bidirectional relay OFDM system, all relays are allowed to forward the same subcarrier pair so as to improve the diversity gain of the system; and based on that, a power distributing and subcarrier pairing combined method with a goal of maximizing system capacity is provided. In order to simplify the computation complexity of an optimization problem, a novel power distributing method based on a Cauchy inequality and a bisection method is provided, and the method comprises the steps of preferably distributing and fixing a power inside the subcarrier pair, converting an optimization model into a typical two-dimensional optimization problem, and then solving via a Hungary algorithm and a subgradient algorithm. The resource distributing combined algorithm provided by the invention is superior to the traditional optimal relay selection algorithm and spaceless diversity gain algorithm in system capacity performance.

The invention discloses an OFDM secure transmission method combining subcarrier pairing and signal inversion. According to the method, subcarrier serial numbers are re-sequenced on the basis of knownchannel state information, subcarriers are divided into two parts by a midpoint adopted as a boundary, wherein the first half of the subcarriers are set to be poor carriers, and the second half of thesubcarriers are set to be good carriers; pairing mapping relationships are defined between poor channels and good channels; inversion signals and useful signals are sent separately, and a receiving end receives the signals in a combined manner; the average bit error rate of a system and one lower bound of the secrecy capacity of the system are derived by using the theory of the sequential statistic theorem; and simulation verification is carried out, and simulation results show that the method of the invention achieves a good anti-eavesdropping effect, satisfies high security transmission requirements, and has certain stability and practicality.

The invention provides a multicast resource scheduling method based on subcarrier combination. The method comprises the following steps: sending same information to two subcarriers; using the two subcarriers as one subcarrier (named as 'combination'); and confirming a sending rate on the combined subcarriers according to a receiving SNR (Signal Noise Ratio) of the poorest user which is estimated after combining the received signals on the two subcarriers at the maximum ratio. According to the method, after the subcarriers are combined, a freedom degree of diversity gain is supplied, the combination/non-combination is self-adaptively selected, and the subcarrier pair scheduling and the power distribution between the subcarriers are optimized, so that the whole multicast service rate of the system is increased. According to the method provided by the invention, the problem of relative low service rate of the present multicast system is solved as far as possible by reasonably scheduling the present resources without adding the extra cost of the system resource. Meanwhile, the invention provides a simplifying method for the corresponding subcarrier pair and a decoupling method for the power distribution between the subcarriers.

The invention discloses a wireless energy-carrying communication method based on OFDM amplification forwarding cooperative relay, and belongs to the field of cooperative communication. The method is realized based on a relay amplification forwarding system model, and comprises a source node S, a relay node R, a destination node D1 of the source node and a destination node D2 of the relay node. Thewireless energy-carrying communication process comprises two time slots, in the first time slot, a source node S broadcasts information outwards, a relay node R uses one part of subcarriers for information decoding, the other part of subcarriers are used for energy collection, and D1 receives information directly transmitted by the source node S. And in the second time slot, subcarrier pairing iscarried out, the relay node R forwards the information of the source node S to the destination node D1 by utilizing the energy collected in the first time slot and the paired subcarriers, and also forwards the information of the relay node R to the destination node D2 by utilizing the rest subcarriers. The cooperative relay technology and the wireless energy-carrying communication technology arecombined, the energy efficiency and the spectral efficiency of the transmission system are improved, and the overall performance of the system is improved.

The invention relates to a resource allocation method under high-speed rail train-mounted base station communication architecture. The resource allocation method aims at the train-mounted base station communication architecture, and is characterized by maximizing capacity of a communication system through resource allocation under an OFDMA (orthogonal frequency division multiple access) modulation mode. The resource allocation method under the high-speed rail train-mounted base station communication architecture mainly includes: establishing a capacity function under the high-speed rail train-mounted base station communication architecture; allocating subcarriers to a plurality of users; achieving subcarrier pairing for a base station end and a train-mounted mobile base station end; respectively allocating subcarrier power to the base station end and the train-mounted base station end. The resource allocation method under the high-speed rail train-mounted base station communication architecture is of great significance in system performance optimization under high-speed rail scene communication architecture.

The invention belongs to the technical field of cooperative transmission, and discloses a multi-dimensional resource optimization algorithm for an incremental AF-OFDM cooperative network. The algorithm comprises the steps: obtaining the channel state information of all subcarriers in all time slots; building an optimization model which takes a network service life m as the target according to a multi-dimensional resource optimization algorithm, calculating the optimal power distribution on all subcarriers in all time slots, determining optimization variables in a transmission process: incremental strategy, subcarrier pairing and relay selection; enabling a source to broadcast data on each subcarrier in the first time slot in a transmission process of useful data through the calculated power, enabling a relay and a target node to receive the data, determining a transmission strategy of the second slot according to the incremental strategy, i.e., enabling the selected relay to transmit the information to the target node on the paired subcarrier through the calculated power; or enabling the source to transmit new data to the target node on the paired subcarrier through the calculated power. The method improves the spectrum utilization rate, effectively employs the limited energy, spectrum and equipment resources.

The invention discloses a signal processing method applied to an optical non-Hermitian symmetric OFDM receiver, and the method comprises the following steps: after timing synchronization is finished, directly carrying out real number FFT operation on a received signal without recovering a corresponding complex signal again, so the calculation complexity is reduced; adopting a single training sequence, on the basis of a traditional LS channel estimation method, carrying out the subcarrier pairing average processing on the basis that preliminary channel estimation on all data subcarriers is obtained, so the system noise interference is restrained, and the accuracy of channel estimation is improved; and finally, carrying out channel equalization processing on the received data by utilizing the channel estimation after the pairing and averaging, and reconstructing a received QAM symbol. According to the non-Hermitian symmetric orthogonal frequency division multiplexing receiver, the hardware implementation complexity of the non-Hermitian symmetric orthogonal frequency division multiplexing receiver can be reduced by replacing the traditional complex FFT algorithm with the real FFT algorithm, and in addition, the accuracy of channel estimation can be improved by using the channel estimation algorithm based on subcarrier pairing average, so the performance of the receiver is improved.

The invention discloses a downlink resource allocation method for a multi-base-station OFDM system, which comprises the following sub-steps of: S1, initializing average power of each base station on each subcarrier, and acquiring rates between different base stations and different subcarriers; S2, performing base station-subcarrier pairing according to the rates between different base stations anddifferent subcarriers; S3, performing power distribution on the base station-subcarrier according to a base station-subcarrier pairing result; and S4, distributing power grid electric energy and solar energy according to the base station-subcarrier power distribution result. According to the method, base station-subcarrier distribution and power distribution methods are provided, and the maximumsystem sum rate is achieved. Further, a power system where the collected energy and the power grid coexist is used, so that the effects of saving energy, reducing emission and realizing green communication are achieved, and the power consumption of the power grid by the base station can be effectively reduced.

This application provides a resource allocation method and device for an OFDM relay system. Based on the channel gain from each subcarrier to the relay, all subcarriers are divided into M subcarrier groups, wherein each subcarrier group has It includes P subcarriers, and, according to the M subcarrier groups, the objective function of the capacity of the OFDM relay system is simplified, in the simplified objective function, the minimum calculation unit is the subcarrier grouping, and then using the The simplified objective function is to pair the M subcarrier groups, because the simplified objective function no longer uses the subcarrier as the minimum operation unit, but uses the subcarrier group as the minimum operation unit. Compared with the subcarrier, The subcarrier group reduces the scope of carrier pairing, and therefore, can reduce the complexity of subcarrier pairing without affecting system performance.