39results about How to "Improve space reuse" patented technology

Provided are a method of performing contention based channel access by classifying a contention period into a beamformable contention period in which a beamforming is allowed and a non-beamformable contention period in which the beamforming is interrupted so as to resolve an issue regarding channel access occurring due to an introduction of a directional antenna for handling a path loss in a wideband wireless communication system according to an embodiment of the present invention, and a method for maximizing a spatial reuse gain by managing, for each direction, information about a transmission time of a message received from a dispersion device.

The invention relates to a routing method suitable for the static ad hoc formation. Aiming at the special organization structure of the static Ad hoc formation, a centralized topologic control is carried out inside the ad hoc formation; the formations are clustered according to the results of the topologic control; and a new double-frequency multi-stage routing method is adopted so as to ensure the reliable and quick routing establishment and the data transmission inside the formation and among the members inside the formation. The method is characterized in that the method includes the following steps: the topologic control in the formation, the establishment of the formation network structure, the maintenance of the formation network structure, the search of a transmission router, the maintenance of the transmission router, the routing error control and the re-establishment of the router. By adopting the method, the reliable and quick routing establishment and the data transmission in the formation and among the members inside the formation can be realized, the interference in the wireless transmission can be reduced, the network capacity can be further improved, the node service life is prolonged, and the network survival time is increased.

The invention provides a method for implementing an aeronautical Ad hoc network STDMA (Self Organizing Time Division Multiple Access) protocol based on a directional antenna. Through adoption of a directional antenna model, node directional transmission and directional reception, the spatial reuse is enhanced. Meanwhile, a method of combining fixed time slot assignment with dynamic time slot assignment is adopted, namely, the fixed time slot assignment is realized on the basis of a polling strategy, and optimization of dynamic time slot scheduling is realized in combination with an ADS-B system. In the case of emergency demands, reservation of additional time slots is performed, so that time delay of services can be ensured at a certain degree, and an emergency data transmission demand can be met. Through adoption of the method, time slot resources are fully utilized, and the spatial reuse and network throughput are enhanced.

The invention discloses a distributed graph coloring link dispatch scheme of a wireless sensor network based on a graph coloring algorithm. According to the scheme, firstly, partial interference information is obtained through packet switching among nodes; secondly, a graph vertex coloring analysis is carried out on a generated localized network conflict graph; thirdly, the conflict-free time slot allocation of a wireless sensor network link is obtained. To improve the coloring success rate, two mechanisms are provided. One mechanism is a broadcast safeguard mechanism for improving the broadcast information delivery rate, and the other mechanism is a conflict processing mechanism for solving the coloring conflict problem. According to the distributed link dispatch scheme, the problems of packet loss, delay and the like caused by multi-hop transmission are solved, and the transmitting energy consumption is reduced. The result of the network simulation shows that the distributed graph coloring link dispatch scheme has the advantages over a conventional link dispatch method on the aspects of energy consumption, the space reusing rate, the packet loss probability and the like.

The invention provides a carrier sensing method based on a dynamic idle channel assessment threshold. According to the method, the existing carrier sensing mechanism is improved, and a CCA (Clear Channel Assessment) threshold is adjusted and an effective range of an NAV (Network Allocation Vector) is controlled according to the channel condition, so that the concurrent transmission in a network is increased and the network throughput is improved. According to the method, the CCA threshold is dynamically computed and adjusted according to the receiving power, so that the spatial reuse of the network can be effectively improved, meanwhile, through carrying an interference margin and a probability of acceptance at a CTS (Clear To Send) group, the range of action of the NAV in the CTS group is effectively controlled, and the spatial reuse is further improved, so that the network throughput is improved.

The invention discloses a method which can realize power control and the device thereof, and a method to manage the neighbor list. Wherein, the device to realize power control includes a transmitting module arranged at the source node to transmit a power transmitting information packet which has the value of the transmitting power, a storage module arranged at the source node and connected with the transmitting module to store the power transmitting information, and a receiving module arranged at the destination node and connected with the transmitting module to receive the information packet. The device also includes a first module arranged at the destination node and connected with the receiving module for obtaining the modification information according to the value of the transmitting power, a second module arranged at the source node and connected with the first module and the storage module for modifying the transmitting power according to the modification information. Adopting the device can save energy and increase the communication channel space reuse degree while at the same time keeps the network a fine connectivity by the nodes in the wireless sensor network.

The invention provides an underwater acoustic parallel transmission method based on active time reversal. Spatial weak correlation of channel response between different links caused by complex underwater acoustic multipath propagation is utilized; the space-time focusing of the signal at the receiving position is obtained, the influence of inter-link interference in a parallel transmission scene is effectively suppressed by combining up/down sampling, the spatial multiplexing degree is improved, and the transmitting power of the transmitting node is minimum on the premise of meeting the specific service quality of the receiving node by combining a power control method. According to the method, the broadcast characteristic of an underwater acoustic channel is weakened, and the key effect ofeffectively isolating signal interference between adjacent links in a distributed multi-hop environment is achieved; the up/down sampling method further suppresses inter-link interference and inter-symbol interference, so that the spatial multiplexing degree is further improved. According to the power control method, the transmitting power is saved on the premise that inter-link interference is effectively suppressed, and the method is endowed with effectiveness in an underwater acoustic parallel transmission scene due to the characteristics.

A data communications network includes a ring configured for spatial reuse, such as a resilient packet ring. A first bridge is coupled to the ring and to an end station such as an interworking bridge or router. A second bridge coupled to the ring learns an association between the first bridge and the end station by monitoring packets originated in the network by the end station and sent on the ring by the first bridge. The second bridge learns the association by obtaining an identifier of the first bridge and an address of the end station from received packets. When the second bridge receives packets destined for the end station, the packets are forwarded as broadcast transmissions on the ring if the association between the first bridge and the end station has not yet been learned, and are forwarded as unicast transmissions to the first bridge on the ring if the association between the first bridge and the end station has been learned.

The invention discloses a user clustering method and system based on a large-scale MIMO-NOMA system, and a medium, and the method comprises the following steps: 1, determining a channel matrix H according to a selected channel model, calculating the channel gain of a user, and carrying out the sorting; 2, determining boundary users and confirming an initial cluster head by calculating the channel coherence degree of the users; 3, calculating the channel coherence degree between the cluster head set and the candidate user set, setting a threshold value, selecting all cluster heads, and determining a cluster head set gamma; 4, calculating the channel coherence degree and channel difference between the remaining users and the cluster head set, setting a channel coherence degree threshold value delta 2, and finally determining the user grouping condition. The user clustering algorithm provided by the invention not only is beneficial to eliminating inter-cluster interference and increasing multiplexing gain, but also has better frequency efficiency performance compared with a traditional OMA structure under the same condition.

A method of selecting antenna segments for transmission and/or reception in a MIMO wireless transmission system using sectorized directional antennas, includes the steps of selecting, from an initial set of ranked link antenna patterns, a link antenna pattern having the best average rank, at predetermined time intervals, successively selecting a subset of link antenna patterns having average ranks within a predetermined distance to the best average rank, determining an average link performance of the link antenna patterns selected in the preceding step, determining an average rank of the link antenna patterns, for which the average link performance has been determined in the preceding step, selecting the link antenna pattern having the best average rank, and repeating the process at the next predetermined time interval.

The invention discloses a multi-access scheduling method based on a directional antenna, which is characterized in that on the basis of a multi-access protocol of an omnidirectional distributed wireless ad hoc network adopting a reservation mechanism, resource scheduling is carried out by adopting a mode of periodically interacting scheduling information units, and nodes continuously update a local scheduling information linked list through periodic interaction control messages; and when the node performs time slot authorization, selecting an idle time slot or a time slot meeting a multiplexing condition to perform authorization by traversing a local scheduling information linked list, thereby realizing multiplexing of the data time slot. According to the invention, resource scheduling is carried out by periodically interacting scheduling information units. And the nodes continuously update the local scheduling information linked list through periodic interaction control messages. When resource authorization is carried out by an authorization node, authorization can be carried out only by traversing a local scheduling information linked list to select an idle time slot or meeting a multiplexing condition. The multiplexing of data time slots is realized, the spatial multiplexing degree of the distributed wireless ad hoc network is improved, and the network capacity is further improved.