43 results about "Spatial division multiple access" patented technology

Some demonstrative embodiments of the invention include a method, apparatus for concurrently transmitting data to two or more wireless stations.

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.

Methods and systems are provided for assigning channels in a spatial division multiple access communication network. The network includes a plurality of conventional channels some of which are configurable to be shared concurrently by plural subscribers. The method includes determining combinations of subscribers from the existing subscribers. Enhancement activities are invoked to create optimal combinations of existing subscribers. Existing subscribers are reassigned as necessary to share channels thereby freeing resources for new subscribers.

A method and system for assigning unique words in an SDMA (spatial division multiple access) communication system is provided. A network management system logically arranges cell stations into clusters of stations, and monitors for a heavy traffic condition. Responsive to determining that a heavy traffic condition exists, the network management system may 1) redistribute unique words within a single cluster; 2) move one or more cell stations from a busy cluster to a less busy cluster; or 3) create a new cluster, and move cells from one or more busy cluster into the new cluster. In this way, the communication system continually adapts so that more unique words are made available at cell stations having heavier communication demands.

A method, system and communication network for transmitting information signals via uplink (UL) collaborative SDMA, in a wireless communication system. Base station receiver estimates a channel gain associated with the transmission path(s) of each user and keeps a matrix of normalized covariance, between users. Based on the estimated channel gain and the normalized covariance, ULS utility is able to compute channel capacity. Based on capacity estimates of (1) the multiplexed user signals and (2) the individual user signals, signals are either multiplexed for UL SDMA or are transmitted individually. An optimal selection of multiplexed signals may be based upon: (1) a cross user interface measurement; and (2) a selection mechanism based on eigen-decomposition techniques. The ULS utility enables a UL scheduler to pair information signals with clear spatial distinction and minimal correlation, based on capacity evaluations.

Methods and systems consistent with this invention receive a plurality of transmitted signals in a receiver having a plurality of receive elements, wherein each transmitted signal has a different spatial location. Such methods and systems receive the plurality of transmitted signals at the plurality of receive elements to form a plurality of receive element signals, form a combined signal derived from the plurality of receive element signals, and detect each of the plurality of transmitted signals from the combined signal by its different spatial location. To achieve this, methods and systems consistent with this invention generate a plurality of arbitrary phase modulation signals, and phase modulate each of the plurality of receive element signals with a different one of the phase modulation signals to form a plurality of phase modulated signals. Such methods and systems then combine the plurality of phase modulated signals into a combined signal, generate expected signals, and cross- correlate the combined signal with the expected signals to form correlation signals. Such methods and systems then store the correlation signals in a correlation signal memory and analyze the correlation signals to extract information from the transmitted signals.

A method, a system and a receiver device provide timing and frequency correction in a spatial division multiple access (SDMA) system. A timing and frequency correction (TFC) logic / utility obtains a timing error estimate by using pilot symbols on a slot of six tiles. The TFC logic estimates the timing error based on pilot phase differences between unique pairs of tiles when the frequency separation of the tiles is less than a threshold value. When none of the unique pairs of tiles satisfies the threshold value, the TFC logic estimates timing error based on an exhaustive search for each candidate phase error value. The TFC logic performs timing error correction via a timing error estimate based on pilots from the symbols received on each antenna. The TFC logic performs inexplicit frequency error correction according to phase differences based on relative symbol indices.

The embodiments herein provide a system and method for terrestrial to terrestrial or terrestrial and space or space to space communication systems, with millimeter waves. The system enables narrow angle beam and wide angle beam communication between receivers and transmitters that are in relative motion with other receivers and transmitters in the system. The system provides uninterrupted service and good spectrum utilization by combining Spatial Division Multiple Access (SDMA) and Frequency Division Multiple Access (FDMA) technologies. The system minimizes overall power required by a communication system by dynamically enabling and disabling specific channels based on user-availability and need. The system also increases or decreases power based on channel quality in order to maintain desired bit-rate of communication. The system also covers a large service area through a plurality of narrow angle signal beams.

A method and system for assigning unique words in an SDMA (spatial division multiple access) communication system is disclosed. A base station has a set of available unique words from which to select and assign unique words. The base station prioritizes the set of unique words by determining which unique words are likely to interfere with adjacent base stations, and setting those words to a low priority. In this way, over time, the base station assigns unique words that have a lower level of correlation to allow for better signal differentiation and improved communication sensitivity. When a mobile device enters a base station's geographic area, it generates an establish request message that indicates what unique word it is using in the adjacent cell. The base station extracts this unique word, and sets it to a low priority in its set of unique words. The base station is therefore able to assign unique words that facilitate improved communications.