585 results about "Outage probability" patented technology

The outage probability in an under-addressed optical MIMO system may be reduced by configuring an intra-link optical mode mixer to dynamically change the spatial-mode mixing characteristics of the link on a time scale that is faster than the channel coherence time. Provided that the MIMO system employs an FEC code that has a sufficient error-correcting capacity for correcting the amount of errors corresponding to an average state of the MIMO channel, this relatively fast dynamic change tends to reduce the frequency of events during which the number of errors per FEC-encoded block of data exceeds the error-correcting capacity of the FEC code.

The invention provides a time delay and bandwidth resource-based relay selection method aiming at broadcast and telecommunication services. The method comprises the following steps of: obtaining a system interruption selection decision value by acquiring time delay information and bandwidth resource information of a node, and selecting a relay node by using the decision value as a judgment threshold. Meanwhile, the invention provides an optimal relay selection cooperative communication method for minimizing interruption probability, and provides a relay routing selection method for supportingmulti-path transmission. The relay routing selection method can dynamically select proper routing according to the change of a network. The method can expand the coverage range of cells and eliminateor reduce communication blind points so as to increase the throughput of a system, improve the spectrum frequency of the system and enhance the quality of services.

A relay selection method giving consideration to channel conditions and traffic states in multi-user cooperative communication is characterized by introducing a traffic arrival model which can embody traffic burstiness and self-similar characteristic to each user of the network, then comprehensively considering the different QoS requirements of each user traffic, and selecting the direct transmission mode when the channel conditions meet the threshold of signal to noise ratio corresponding to the minimal transmission rate requirement according to the current real-time channel condition and the traffic state; and based on the principles of proportional fairness and user satisfaction, selecting a cooperative partner as the relay user to participate in cooperative transmission when the channel conditions are less than the threshold of signal to noise ratio corresponding to the minimal transmission rate requirement and the cache region at the relay end is not full according to the multi-optimization objective of relay selection, so as to reduce the outage probability of the source user and the influence on the traffic transmission of the relay user, improve the traffic transmission performance of the source user, minimize the influence on the traffic transmission performance of the cooperative user, ensure the different QoS requirements of the user traffics and improve the communication reliability of the cooperative relay system.

A relaying selection and cooperative communications method provides a threshold selection criterion for forming a reliable group of relay stations (RSs) based on one or more design criteria. Possible design criteria include an outage probability constraint and a throughput constraint. The threshold value is selected according to, for example, transmission paths (e.g., line-of-sight, obstructed-light-of-sight, non-light-of-sight) or channel conditions (e.g., signal-to-noise-ratio) between the base station (BS) and the RSs (i.e., BS-RSs link) and between the RSs and the mobile station (MS) (i.e., RSs-MS link), respectively.

The invention provides a resource configuration method and system for terminal direct communication, equipment with base station function and a terminal. The resource configuration method suitable for the equipment with the base station function and used for terminal direct communication comprises the following steps: acquiring use condition of time frequency resource of the equipment with the base station function, and / or status information of each D2D terminal in the coverage range of the equipment with the base station function; determining a configuration mode for configuring the time frequency resource for each D2D terminal according to the use condition of the time frequency resource of the equipment with the base station function and / or the status information of each D2D terminal; and distributing the time frequency resource for terminal direct communication for each D2D terminal according to the configuration mode so that each D2D terminal can perform the terminal direct communication according to the distributed time frequency resource. Through the adoption of the technical scheme provided by the invention, the D2D communication outage probability can be effectively reduced, the D2D communication service continuity is guaranteed, and meanwhile, the high communication quality in D2D communication of the D2D terminal is guaranteed.

A method for determining a power outage probability of an electrical power grid for a time period, the method comprising the following steps carried by a processor of a data processing unit:dividing the time period into several time intervals,determining a power generation capacity of a power generation facility and an energy storage unit size for an energy storage unit for said time period,determining an effective load unit demand for each time interval from a load unit demand of a load unit for each time interval, andcomputing the power outage probability using a grid parameter that comprises the power generation capacity, the energy storage unit size and the effective load unit demand, wherein the grid parameter is optimized for its maximum value with respect to all time intervals of the time period

The invention provides an inter-cell handover method of train-ground communication based on cooperative multipoint transmission in a high-speed mobile environment, which is applicable to an LTE (Long Term Evolution) and an evolution system of the LTE. The method mainly comprises the following steps of: judging whether a train enters into an overlay region according to reported real-time speed information and position information of the train; meanwhile, judging whether the quality of current signals is lower than a pre-set threshold value according to measurement information; if any condition is satisfied, activating the cooperative multipoint transmission (CoMP) between a current base station and a front target base station; sharing downlink data on a data surface of a vehicle-mounted platform between the adjacent two base stations through the CoMP technology and then sending the data to the vehicle-mounted platform; converging uplink data on the data surface of the vehicle-mounted platform through the CoMP technology into a source base station through a communication link of the adjacent two base stations; in the process, if a handover triggering condition is satisfied, handing over data of a control plane into the target base station. The method provided by the invention has the advantages of high handover success rate, low outage probability and high frequency spectrum utilization rate and does not need to change the base station and the vehicle-mounted platform, so that the method is easy to realize.

An apparatus for enabling dual mode communication may include a processor. The processor may be configured to receive (102), via a source cell, an indication of service availability for a particular service in a target cell, determine (104) whether a current transmission format of the target cell is indicative of the particular service being available at a region proximate to an edge of the target cell, switch to communication with the target cell from communication with the source cell in response to a determination that the current transmission format of the target cell indicates that the particular service is available’ at the region proximate to the edge of the target cell, and trigger (110, 112, 130) the target cell to make an adjustment (120, 132) to the transmission format to cover cell edge area in response to a determination that the current transmission format of the target cell indicates that the particular service is not available at the region proximate to the edge of the target cell. A corresponding method and computer program product are also provided.

The invention relates to a joint radio resource management method based on a cross-layer and used to a self-adapting MIMO-OFDM system, comprising: when a plurality of users initiate access requirement, a classifier processes to classify according to service types of the access requirement, and CAC module decides if the access requirement is allowed to accept according to different QoS requirements of a heterogeneous service and resource conditions; a priority scheduling mechanism faces the users, and a scheduler processes to schedule for the heterogeneous service types, different QoS requirements, and user preference information according to priority rules, and transmits information to a physical layer module, so as to determine the users of each time slot which is provided with resource allocation options; the physical layer adopts a resource allocation algorithm to allocate sub-carriers, loading bit streams and allocate corresponding transmission power according to data link layer information, and designs a net utility function for each classification on the base of the game theory, and transforms a target of pursuing net utility function into solving a non-cooperation game process. Compared with traditional methods, the method shows better performance advantages on outage probability, degree of satisfaction of the users for the service and system throughput.

The invention relates to a vehicular wireless communication field technology, in particular to a relay selection method and a multi-access control (MAC) protocol suitable for various mobile scenes. The invention discloses a relay communication method based on a cooperated MAC protocol in a vehicular automatic organization network. A relay is jointly selected according to a data rate and the mobility; the data rate is limited, so that the number of effective relays and fed-back information amount are greatly reduced, and the effectiveness of relay selection is improved; the selected relay group has relatively high link quality and can meet demands of various mobile scenes; the interruption probability and the error rate of a system can be reduced; and therefore, reliable transmission of data in the network can be effectively realized.

This invention relates to a route device for increasing service quality of day-base information networks including an input module, an initializing module, a negative computation module, a positive commutation module and an output module. This invention also relates to a route method including: transforming the current network to a first topological structure, transforming the link price of the first topology to generate a second topological structure according to the interruption probability of the link, computing the shortest path based on time delay from the nodes to the destination node in the second topological structure and judge if the time delay value of the shortest path from the destination node to the source node meets the restriction condition, if not, the time delay value of the shortest path from the nodes to the destination node is registered and the shortest path based on link price from the destination node to the source node is computed, judging if the time delay value of said path meets the restriction condition, if so, said path is the optimum one, otherwise, the positive computation program is called to search for the optimum path from the source node to the destination.

The invention discloses an access network selection method based on a neural network and a fuzzy logic, which mainly solves the problem that the future load change and the parameter uncertainty of a candidate network in the network selection process influence user performance. The method comprises the following implementation processes of: collecting the current load information of a located network and user received signal intensity information by the base station of each candidate network; forecasting the change tendency of the future load of each candidate network by utilizing an integrated BP (Back-Propagation ) neural network; processing the network load and the user received signal intensity information by utilizing the normalization fuzzy logic; calculating the technical indexes of the candidate network by utilizing cost functions; comprehensively balancing the technical indexes, the network parameters and the user requirements of the network by utilizing a multi-objective decision to obtain the proper access degree of each candidate network; sending the proper access degree of the network in which the base station is to the user through a wireless enabler by each base station; and after the user compares, selecting the candidate network with the maximum proper access degree as an objective network. The invention can effectively reduce the blocking probability when the user accesses to the network and the interrupting probability in the serving process to realize a function for the user to select the best access network.

A method and system for performing call admission control in wireless communication systems is disclosed. Resource units required by a new user are assigned based on an outage probability of each uplink timeslot. The outage probability of each timeslot is updated as the resource units are assigned so that each resource unit assignment results in the lowest possible contribution to total outage probability. Once all of the resource units are assigned, the total outage probability is computed based on the resource allocation. If the total outage probability is below a predetermined value, the new user is admitted. If the total outage probability is above the predetermined value, the new user is rejected.

A joint scheduling and grouping technique for throughput maximization is disclosed for an uplink space-division multiple access (SDMA) system under proportional fairness constraints, when the receiver employs successive group decoding. We consider a slow-fading narrowband MIMO multiple access channel (MAC) in which multiple users, each equipped with multiple transmit antennas, communicate to a receiver equipped with multiple receive antennas. The users are unaware of the channel state information (CSI) whereas the receiver has perfect CSI and employs a successive group decoder (SGD). For an open-loop system, achievable outage probabilities are obtained for the case where an outage must be declared simultaneously for all users (common outage) as well as the case where outages can be declared individually for each user (individual outage). We then derive the optimum successive group decoder (OSGD) that simultaneously minimizes the common outage probability and the individual outage probability of each user, over all SGDs of permissible decoding complexity. For each channel realization, the OSGD is also shown to maximize the error exponent of the decodable set of users. An adaptive SGD is derived which not only retains the outage optimality of the OSGD but also minimizes the expected decoding complexity. Asymptotically tight (in the limit of high SNR) affine approximations are then obtained for the weighted sum common and individual outage capacities and the symmetric outage capacities. Limiting expressions for the relevant capacities as the number of users and the number of receive antennas approach infinity are also obtained and it is shown that the SGD yields symmetric capacity gains commensurate with the decoding complexity allowed. Simulation results with practical LDPC outer codes show that the OSGD offers significantly improved performance at low decoding complexity.

The invention discloses an energy-carried cooperative CR-NOMA cooperative mode and a relay selection algorithm based on CR-NOMA, comprising: when relay assists two users for information transmission, if the main user is able to decode correctly, then, using all the collected energy to assist the cognitive user to transmit information at the next time slot; otherwise, using the NOMA to continue forwarding the information of the two users; for the multi-relay, proposing the relay selection strategy of the two stages, or solving the set of the correctly decoded relays first; then enabling that the energy remaining and the channel gain from the second jumped relay to the main user are maximized; and solving the closed solution to the interruption probability of the two users and the expression of the throughput. With the invention, while the performances of the main user are ensured, the performances of the sub-user can be increased further so that when the main user reaches the full gain, the cognitive user reaches three-order gain. The energy efficiency of the system is also raised.

The invention relates to the field of wireless mobile communications, and provides a method for managing spectrum resources in D2D communications. The method specifically comprises the steps that in the same cell, a plurality of pairs of D2D users use the spectrum resources which are orthorhombic to spectrum resources used by cellular users for communications; the disturbance variable of same frequency interference which is borne mutually by every two pairs of D2D users in the communication process is obtained; the communication outage probability of each pair of D2D users when same frequency interference happens is calculated; clustering of the D2D users is achieved according to the communication outage probability and the disturbance variable, a plurality of mutually-orthorhombic spectrum resources in the spectrum resources used by the pairs of the D2D users are distributed to each cluster, and all the D2D user pairs in each cluster reuse the same spectrum resource. By means of the method for managing the spectrum resources in the D2D communications, low interference multiplex of the pairs of the D2D users to the same spectrum resource in the same cell in the D2D communications can be achieved.

The invention discloses a full-duplex unmanned aerial vehicle mobile relay system based on minimization of outage probability and a path optimization method thereof. The full-duplex unmanned aerial vehicle mobile relay system based on the minimization of outage probability comprises a single antenna source node, a single antenna destination node and a single antenna unmanned aerial vehicle mobilerelay node; wherein the unmanned aerial vehicle mobile relay node operates in a full-duplex decoding and forwarding mode, flies according to a certain path within a specified flight time, and forwardsthe information of the source node to the destination node. The path optimization method establishes a mathematical model considering the flight speed constraints of the unmanned aerial vehicle, taking the unmanned aerial vehicle flight path as the optimization variable, and aiming at minimizing the total interruption probability of the system. The path optimization method uses the first order Taylor series expansion manner to transform the original optimization problem into a standard twice constrained quadratic programming problem, and then solves with the Lagrangian duality theory and thesubgradient method to obtain a closed form solution of the optimal flight path of the unmanned aerial vehicle relay node, which satisfies the minimization of the outage probability.

The invention relates to a cascading failure search and weak link analysis method based on an operation reliability model. The method comprises steps: initial failure is generated randomly; a DC power flow is calculated, whether a load threshold-crossing line exists in a power system is judged, if yes, a next step is carried out, or otherwise, the operation is stopped; an initial failure set is generated, and through the operation reliability model, the threshold-crossing line outage probability is calculated; the power system state probability is calculated; if the power state probability is larger than a set threshold and the failure scale is smaller than a set threshold, the power state is added to an alternative failure set, and if no state meeting the condition exists, search is stopped; the initial failure set is taken as an alternative failure set, the current alternative failure set is emptied, and the above steps are repeated. Through searching a cascading failure event in different initial failure and analyzing a system weak link, a corresponding system reform scheme is provided, happening of the cascading failure is prevented, a subsequent event is found during an event development process, and further evolution of the cascading event can be prevented.

The invention provides a physical layer security transmission method for keeping a relay and jamming node selection result secret. A wireless transmission network in which hacking nodes exist is established and comprises a source node S, a destination node D, M intermediate nodes T<1>, T<2>, ..., T<M>, and the K hacking nodes E<1>, E<2>, ..., E<K>, the whole transmission process includes two stages, wherein in the first stage, the source node broadcasts information s and considers that the information s can be successfully decoded in all the intermediate nodes in the stage; in the second stage, the selected intermediate nodes forward information to the destination node through a decoding forwarding protocol, and jamming nodes transmit jamming information to the hacking nodes. The security outage probability performance of the relay and jamming node selection result is similar to that of an optimal selection result acquired through a method of exhaustion, and the relay and jamming node selection result has high security outage probability performance; only statistical channel state information of a hacking user needs to be acquired in the relay and jamming node selection process, and high practicability is achieved; the relay and jamming node selection result is kept secret to the hacking nodes, and the transmission security of confidential signals is guaranteed.

The invention discloses a relay transmission method based on physical layer safety in an eavesdropping user randomly distributed scene. The method comprises the steps of 1), obtaining a safe interruption probability of two-hop relay transmission after two times of independent eavesdropping coding is carried out in the eavesdropping user randomly distributed scene based on a random geometric theory; 2), establishing an optimization problem of maximizing a safe transmission speed under the condition that the total transmitting power of a source node and a relay node is limited; and 3), obtaining a relay transmission method capable of maximizing the safe transmission speed through solution of the established optimization problem, wherein the method comprises two parts of power distribution and codebook rate design. According to the method, under the condition that the specific locations of the eavesdropping users are unknown, the communication reliability and safety are taken into comprehensive consideration, the safe interruption probability constraint is satisfied, and moreover, the safe transmission speed is maximized.

This invention provides a switch protection method for links among satellites including: 1, generating service paths according to the service requirement of a terminal, 2, computing the interruption probability of each link in the service routes to select protection links for interruption protection, 3, setting up switch protection backup route between two switch nodes in the protection link, 4, when the protection link switches paths, it switches the current service between two nodes to said back up path. This invention applies a mode of resuming protection locally to recover the interrupted paths because of switch quickly to guarantee the durative of service communication and that related QoS target will not be broken.

The invention relates to a method for carrying out grouping cooperative communication on multiple users based on network encoding technology, which means that grouping is carried out on the multiple users in a special grouping way in a cellular relay network; then, each group of user data is encoded and transmitted by a relay node through the network encoding technology, so that the relay transmission efficiency is improved, and the problem of low relay upstream transmission efficiency can be solved; and when the user is positioned at the edge of a subdistrict, the method can improve the transmission performance, and the coverage range of a base station in the whole subdistrict is enlarged. The method comprises the operation steps of: setting the functions of the relay node in an initialized way, channel estimation and base station selection, judgment of a cooperative partner, grouping transmission executed by the user and self-adaptive centralized control executed by the base station. The method fully utilizes the channel characteristics of cellular cell users, and can be used for grouping the multiple users, thus practically improving the relay transmission efficiency and the transmission performance of the edge user, and reducing the outage probability of the system.

The invention discloses two robust beam forming methods for an MISO wiretap channel based on interruption probability constraints. Two robust beam forming schemes for the MISO wiretap channel are provided, a method of bisection, semidefinite relaxation and a Bernstein-type inequality are utilized to transform a nonconvex problem with the interruption probability constraints into a series of semidefinite programming problems in the absence of artificial noise assistance, so that the optimal robust beam forming design is obtained; the total transmitting power is divided into two parts of a useful signal and artificial noise in the presence of artificial noise assistance, through transforming the nonconvex problem with the interruption probability constraints into the semidefinite programming problems, the optimal design of robust beam forming of the useful signal and a covariance matrix of the artificial noise is obtained; the secrecy rate of a communication system is effectively improved, the wiretapping capability of a user is reduced and the security of the communication system is improved.

The invention belongs to the mobile communication and particularly relates to wireless cache network nodes in the mobile communication which can store the content required by users in the vicinity in advance during the network idle time. The invention provides a cache distribution method for D2D wireless cache network. The distribution method is a cache distribution method based on low content interrupt probability in the interference environment, which can effectively reduce the redundancy degree of the cache in the wireless network, meets the need of low interruption probability under the condition of meeting network QoS, and improves the content delivery capability of network; and meanwhile, the distribution method is suitable for the actual scene with dynamic changes.

The invention provides a district switching method in a long-term evolution system, which comprises the following steps: a source base station receives a measuring report reported by a terminal, and then, the source base station makes a switching decision and sends a switching preparation request to a destination base station; after receiving the switching preparation request, the destination base station selects a candidate district for resource allocation failure in a destination district to a user and sends a switching preparation failing message to the source base station, wherein the message carries information of the candidate district; and after receiving the switching preparation failing message, the source base station makes a switching decision again according to the information of the candidate district in the message. The district switching method in the long-term evolution system can be used for starting a switching attempt again under the condition that the first switching preparation fails, thereby increasing the opportunity of the switching, shortening the time for the second switching preparation, reducing the outage probability caused by unsuccessful switching, and greatly improving the successful rate of the switching of the whole system.

The invention relates to a multi-antenna non-trusted relay system based on limit feedback, and a transmission method for feedback bit number self-adaptive selection of the multi-antenna non-trusted relay system based on limit feedback. The model is a single-relay communication system comprising a signal transmitting source, a non-trusted relay and a legal receiving node. In the strategy, the transmitting source only needs to know a mark number of a channel quantified in a codebook and does not need to know channel complete state information (CSI). Safety interruption probability is minimized via reasonable selection of the feedback bit number under the situation of reaching the requirement for a receiving signal interference noise ratio (SINR) threshold so that safety and reliability of the system are both realized.

The invention discloses a chance relay-selection method for a cooperative communication network under tapping environment. The chance relay-selection method comprises: establishing a wireless cooperative communication network which includes a source node S, a target node D, M standby relay nodes R1, R2, ..., RM, and a tapping user E; transmitting information by a decode forwarding protocol during a transmitting process, wherein the whole transmitting process includes two phases: in the first phase, the source node S broadcasts information to the standby relay nodes, and in the second phase, the optimal relay selection and power distribution are performed, and the selected optimal relay node forwards information to the target node D. The chance relay-selection method for a cooperative communication network under the tapping environment is simple in relay selection and power distribution methods and easy to implement, comprehensively considers channel status information of legal users and the tapping user, can obtain better safe outage probability performance, and is relatively high in practical value.

The invention discloses a method for lowering implicit feedback overhead by dynamic threshold under multiple user-multiple input multiple output (MU-MIMO), belonging to the technical field of wireless communication. The method comprises the following steps: (1) dividing a serving cell and a multipoint cooperation cell; (2) after a user detects pilot frequency information, representing channel state information with a signal to noise ratio; (3) selecting an optimal physical resource block; (4) setting outage probability to screen users, and obtaining the dynamic threshold; (5) carrying out thedynamic threshold judgment on the optimal physical resource block; (6) distributing the physical resource blocks by a dispatching algorithm; (7) feeding the channel information back to a serving basestation by the users; and (8) dispatching the information according to the fed channel information by the serving base station. Under the MU-MIMO, the user feedback overhead can be greatly reduced byselecting the optimal physical resource block and setting the dynamic threshold on the premise of basically not influencing the system capacity, and the method is widely applicable for complex network systems and occasions with large user service amount.

The invention discloses a relay selection method for an energy harvesting wireless network. The method comprises the steps that in the acquiring process, an objective function which enables the outage probability to be minimal is established according to the limiting condition of energy harvesting; meanwhile, a heuristic dynamic power distribution and corresponding relay selection method is provided for solving the objective function, in the solving process, the energy acquired by signals from relay nodes are made dynamic, and therefore the precise minimal outage probability in the energy harvesting wireless network is obtained.

The invention discloses a CTCS-3 business oriented GSM-R fast handoff method, which relates to the technical field of train communication, and comprises the steps: firstly, determining the running direction of a train; defining two switch-in channels according to the running direction of the train, wherein one channel is a main channel, and the other channel is a standby channel; and selecting one of the main switch-in channel and the standby switch-in channel as a switch-in channel to achieve the switching, and implementing handoff switching by using the standby traditional PBGT algorithm when the running direction of the train can not be determined. The method omits the measurement and decision process of handoff switching, reduces the protection time required by the switching process and a network overlapping coverage area, saves network resources, greatly improves the switching success rate of a CTCS-3 mobile station when the train runs at a high speed, and also greatly reduces the communication interruption probability of CTCS-3 business.