305 results about "Space-division multiple access" patented technology

Multiple Input Multiple Output (MIMO) technology in conjunction with the IEEE 802.11 standard enables simultaneous communication of data packets to or from multiple users in the same frequency. Spatial divisional multiple access (SDMA) is thus provided. In this way, system capacity can be increased to an extent that depends on available antenna resources and the multipath characteristics of the communication channel. Doubling or quadrupling of network throughput can be achieved.

To provide space division multiple access in a wireless network, plural beams are transmitted within a cell segment. Different information sets are sent in the corresponding plural beams, where one or more of the information sets are detectable by a mobile station depending upon a location of the mobile station in the cell segment. An indication responsive to which of the different information sets is detected by the mobile station is received, and beam selection from among the plural beams is performed according to the received indication.

In the environment of a communication area including a SDM-compatible mobile station for space division multiplex transmission and a SDM-uncompatible mobile station not compatible with space division multiplex transmission, a base station having a plurality of antennas and capable of adaptively changing directivity performs allocation of a mobile station which simultaneously performs space division multiplex transmission (SDM) and space division multiplex access (SDMA) by using a predetermined space division multiplex transmission evaluation criterion and a space division multi access evaluation criterion. By using this radio communication method, it is possible to use the spatial degree of freedom at its maximum and provide a radio communication system having an improved communication capacity.

A system and method for opportunistically designing collaborative beamforming vectors is disclosed for a wireless multiple input, multiple output (MIMO) space division multiple access (SDMA) communication system by sequentially designing beamforming vectors for ranked channels in order to exploit the instantaneous channel conditions to improve per user average SNR performance. Each subscriber station independently transmits information to a base station that allows the base station to determine beamforming vectors for each subscriber station by ranking the subscriber stations by channel strength. Using sequential nullspace methods, the ranked channel matrices are then used to select the channel matrix H_i for the best subscriber station, to design the w_i, v_i for the best subscriber station as the left and right singular vectors of the MIMO channel matrix H_i, to transform the remaining channels and to continue the process until beamforming vectors are designed for all channels.

A system for allocating a wireless resource for a Space Division Multiple Access (SDMA) communication is provided. The system for allocating the wireless resource for the SDMA communication includes: a channel state recognition unit to recognize a channel state of wireless channels generated among adjacent nodes including a source node, a relay node, and a destination node; and a wireless resource allocation unit to control at least one of an amount of channel state information fed back from the destination node to the source node, and a relay level of a relay signal, the relay signal being generated by relaying a source signal transmitted from the source node, according to the channel state.

A base station for communicating with mobile stations in a coverage area of the wireless network. The base station comprises: 1) a transceiver for transmitting downlink OFDMA signals to each mobile station; 2) an antenna array for transmitting the downlink OFDMA signals to the mobile stations using spatially directed beams; and 3) an SDMA scheduling controller for scheduling downlink transmissions to the mobile stations. The SDMA scheduling controller determines a first mobile station having a highest priority and schedules the first mobile station for downlink transmission in a particular time-frequency slot. The SDMA scheduling controller then determines additional mobile stations that are spatially uncorrelated with the first mobile station, as well as each other, and schedules the additional mobile stations for downlink transmission in that particular time-frequency slot according to priority.

Some demonstrative embodiments of the invention include a method, apparatus, and system of performing simultaneous downlink transmission over a wireless medium to a plurality of wireless stations, using Spatial Division Multiple Access (SDMA) in a wireless local area network (WLAN). In one demonstrative embodiment of the invention, the method may include synchronizing transmission of first and second data frames to be received by first and second wireless stations, respectively, such that the transmissions of the first and second data frames end substantially simultaneously. Other embodiments are described and claimed.

A method and apparatus for performing space division multiple access in wireless communications are disclosed. After the receipt of a set of training data from a base station, an estimated channel state information (CSI) is then generated by a mobile station. The CSI is subsequently quantized. The mobile station then determines whether or not the quantized CSI falls within a set of thresholds. If the quantized CSI falls within the set of thresholds, the mobile then sends feedback information to the base station to allow the base station to consider the mobile station as one of the mobile station candidates available for data communications. Otherwise, if the quantized CSI falls outside the set of thresholds, the mobile station then discards the quantized CSI.

The present invention provides a method and an apparatus for communicating data over a network between a communication node, for example, an access point having a first and a second antenna and a first and a second mobile station. The method comprises weighting a first data at the access point to transmit the first data using the first and second antennas so that the first mobile station only receives the first data and weighting a second data at the access point to transmit the second data using the first and second antennas so that the second mobile station only receives the second data. A space division multiple access (SDMA) module may cause a transmission protocol to transmit the first data to the first mobile station on the downlink and transmit the second data to the second mobile station in parallel to the transmission of the first data on the downlink. In a telecommunication system, this substantially simultaneous transmission of the first and second data using a similar carrier frequency in a radio frequency communication over a wireless local area network (WLAN) may increase throughput of a downlink, for example, by a factor nominally equal to the number of antennas at an access point.

Disclosed are systems and methods which select multiple communication beams for simultaneous use such that potential scatters (e.g. reflectors) are not illuminated by simultaneous transmissions. Preferred embodiments of the present invention provide for maximizing aggregate throughput by continuously selecting the best subscriber station combination to be serviced simultaneously, such as based upon their spatial status and Quality of Service (QOS) metrics. Additionally or alternatively, embodiments of the present invention may facilitate demodulation reference using a system common pilot, training sequence, or other system signal.

An apparatus and method for beamforming of a terminal in a Multiple Input Multiple Output (MIMO) wireless communication system are provided. The method includes transmitting sounding signals beamformed through a plurality of beamforming weight vectors in sequence, receiving control information indicative of an uplink weight vector determined by a base station and a maximum channel quality value using the sounding signals and transmitting a transmit signal beamformed with the uplink weight vector via a plurality of antennas.

In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.

Provided are space division multiple access for wireless local area network (WLAN), and channel estimation for the same. A frequency division multiple access technique and a space division multiple access technique based on competition are used together for channel access. The channel access method includes: a competition period for estimating channel characteristics for a plurality of stations and transmitting, to the plurality of stations, downlink schedule information or uplink schedule information based on the estimated channel characteristics; and a data transmission period for performing downlink transmission or uplink transmission with all or some of the plurality of stations in accordance with the downlink schedule information or the uplink schedule information.

In a Vehicular Ad Hoc Network (VANET) a hybrid method combines SDMA (Space Division Multiple Access) and dynamic TDMA (Time Division Multiple Access) that divides the roadway into regions (whose size is larger than the SDMA unit) where each region is allocated a pool of radio channels based on SDMA and may contain a limited number of vehicles. Vehicles within the same region compete for and access the channels using dynamic TDMA. A channel allocation scheme that maps the pool of channels to the regions such that when a vehicle acquires multiple channels (time slots) in a region, the intervals among the channels are as uniform as possible, thus minimizing the waiting time of the messages to be broadcast by the vehicle, which is critical for safety related applications. This solution is referred to as R-SDMA (Region based SDMA).

The invention relates to a vehicle-mounted ad hoc network self-adaptive time slot distributing method based on a time division multiple address (TDMA), the vehicle-mounted ad hoc network self-adaptive time slot distributing method divides a time frame into a left time slot set and a right time slot set, nodes are divided into a left node set and a right node set based on the moving direction of the nodes, and the nodes in the left/right node sets choose competition time slots in the left/right time slot set based on the current geographical location information and according to certain rules. The vehicle-mounted ad hoc network self-adaptive time slot distributing method based on the TDMA reduces the ratio of a connect-in confliction and an amalgamation confliction occurred by the nodes to a large degree; and based on density changes of the nodes sensed by the nodes, the lengths of frames are dynamically adjusted, so that the demand that the nodes swiftly connect-in channels is satisfied; low time delay of the vehicle-mounted ad hoc network self-adaptive time slot distributing method based on the TDMA is authenticated by both theoretical analysis and simulating experiments. Compared with the prior art, the vehicle-mounted ad hoc network self-adaptive time slot distributing method based on the TDMA has the advantages of having less quantities of confliction nodes, higher utilizing ratio of the channels and good expansibility.

The invention discloses a millimeter wave large-scale MIMO system multi-user transmission method based on space division multiple access and interference suppression. A base station is provided with a millimeter wave large-scale uniform panel antenna array; a plurality of single-antenna users receive service from the base station on the same time-frequency resource; according to information of wave beam clusters selected by the users, a universal user set is divided into an interference-free user subset and an interference user subset; the space division multiple access transmission method based on double-layer pre-coded codes is adopted to the interference-free user subset, and the transmission method based on interference suppression is adopted to the interference user subset. According to the method, the advantages of two traditional multi-user transmission methods based on space division multiple access and interference suppression respectively are combined, and the bottleneck that in an FDD transmission mode, downlink channel information of a large-scale MIMO system is difficult to obtain is broken through; meanwhile, the computation complexity problem is solved, it is guaranteed that all the users can receive the service from the base station simultaneously, and considerable system performance and speed performance are achieved at limited feedback quantity.

The present invention relates to a method for connecting a base station and a repeater for a spatial division multiple access, and a repeating method thereof. In order to provide efficient spatial division by using a repeater, data streams are repeated by using a repeating system including at least one repeater for performing wireless communication with a terminal located in a repeating region controlled by using at least one repeating antenna and a base station including a plurality of base station antennas corresponding to the repeating antenna. In this instance, the terminal detects location information on the repeating region to which the terminal belongs by using the pilot signal transmitted by the base station or repeated by the repeater. Location information detected by the terminal is fed back to the base station so that the base station may use it for the spatial division multiple access for simultaneous transmission to many terminals. Therefore, the spatial division multiple access for increasing sector capacity by efficiently combining the base station including multiple antennas and the repeater is available.

Communication operations are optimally conducted by applying space-division multiple access in which wireless resources on a spatial axis are shared among a plurality of users.

By applying an RD protocol to a communication system that conducts space-division multiple access, spatially multiplexed frames in a TXOP are made more efficient. By specifying a frame length for reverse direction frames with reverse direction permission information and having respective transmitters of reverse direction frames make their frame lengths uniform while respecting the specification, AGC operation stabilizes. Also, a transmit start time for reverse direction frames can be specified by reverse direction permission information, and respective transmitters of reverse direction frames can transmit frames at the same time while respecting the specification.

Two-way (full-duplex) wireless links in facilitating network management and improve network performance. Once aspect includes methods for network management using an overlaid network for control signaling. Another aspects include methods to facilitate practical realization and improve performance of some of the network information theoretic configurations, such as Space-Division Multiple Access (SDMA) in uplink and downlink, Interference Channel, and other forms of distributed collaborative signaling schemes. Another aspect includes methods to support cognitive wireless networks.