摘要:
The location of a remote unit (113) within a wireless communication system (100) is determined by all base stations (101) within the wireless communication system (100) initiating a first page (wide-area location page) that is broadcast to the remote unit (113) over a paging channel. The serving and neighbor base stations are determined from the remote unit's (113) response to the wide-area location page, and those base stations are instructed to tune receiving elements to obtain data that will be transmitted by the remote unit (113) during location. A second message (Location Page Message) is then broadcast to the remote unit (113) via the serving base station (101). The Location Page Message instructs the remote unit (113) to periodically transmit a known Remote Unit Location Message (RULM) with increasing power levels for a predetermined number of times so that the remote unit's (113) location can be achieved.
摘要:
A method and apparatus is provided to facilitate coherent communication in a random access channel. In encoding, reference symbols are inserted into a stream of access channel message data symbols and appended to a synchronization message to form a reference coded access channel transmission. Subsequently, the access channel transmission is prepared for transmission over a communication channel by being spread with a spreading code. In decoding, a known synchronization sequence is correlated with a received communication signal to generate a correlation peak when a synchronization message is present. The received communication signal is despread with a spreading code to derive a stream of reference samples and data samples. A channel response is determined from the correlation peak and revised based on estimates derived from the stream of reference samples. Finally, an estimated data symbol is detected from the stream of data samples by utilizing the revised channel response.
摘要:
A method and apparatus is provided for transmitting spread spectrum signals. The transmitter receives data symbols. Subsequently, the transmitter splits each particular set of two received data symbols into a first and second array of data symbols according to either of two algorithms. The first algorithm including providing both data symbols of the particular set to the first and second array of data symbols and the second algorithm including providing one of the data symbols of the particular set to the first array of data symbols and the other of the data symbols of the particular set to the second array of data symbols. Subsequently, the transmitter determines particular channels to transmit the first and second array of data symbols by spreading the first and second array of data symbols with a predetermined length Walsh code. The transmitter accommodates a variable number of data channels by selecting a particular algorithm from a group consisting essentially of a first algorithm and a second algorithm and setting the predetermined length Walsh code in response to the particular algorithm selected.
摘要:
A mobile subscriber unit (MS) location method and system in a spread spectrum channel coding system uses a known spread spectrum location beacon channel (34) that is time division multiplexed with normal code division multiplexed channels (36). Each base station (12, 14 and 16) in a defined service area transmits the known time division multiplexed spread spectrum location beacon signal (34), such as a known location channel, as a spread spectrum location beacon signal at a same time interval. Mobile subscriber units (18) receive the spread spectrum location beacon signal (34) time division multiplexed with the normal CDMA channels (36) and determine their own location using location techniques such as trilateration. Preferably, all of a base station's transmit power is assigned to this special known location channel (34) during transmission.
摘要:
A data transmission system identifies the length of communicated messages and adjusts interleave depth in response to the length of the communicated message. The system provides an efficient method of interleaving both voice data typically having a long message length and packet data typically having a short length.
摘要:
A processing system that is accessible via a number of speech transmission media. Access to the processing system may be made via a mobile radiotelephone, land line telephone, acoustic link or datalink. Access to programs, files and data is based upon the security of the communication media and authentication of the user.
摘要:
An orphan condition is mitigated in a spread-spectrum communication system by determining when a remote unit (113) is likely to become an orphan (315) and adjusting remote unit (113) operating parameters (360) to force additional base stations (101, 102) to be added the remote unit's (113) active set. In particular, when it is determined that a remote unit (113) is likely to become an orphan, T.sub.-- ADD and T.sub.-- COMP are adjusted so that the remote unit (113) is forced to add additional base stations (101, 102) to its active set. Increasing the number of base stations (101, 102) that a remote unit (113) is communicating with greatly reduces the probability that the remote unit (113) will become an orphan.
摘要:
A communication system (100) employs a method (600) and apparatus (101) for conveying a communication signal between a communication unit (105) and a base site (101) that services a sectorized coverage area (103). The communication unit (105) transmits an uplink communication signal (113) to the base site (101). The base site (101) receives (603) the uplink communication signal (113) and determines (605) an approximate location of the communication unit (101) within a first portion (111) of a sector (108) of the sectorized coverage area (103). A downlink communication signal is then transmitted (609, 613) to the communication unit (105) based on the approximate location of the communication unit (105) using an antenna structure that produces a beamwidth (117) narrower than an angular width of the sector (108).
摘要:
A method, performed by a mobile station (119), prevents an active call from being dropped when the mobile station (119) suddenly transitions from a first coverage area (121) to a second coverage area (122) in a code division multiple access (CDMA) cellular radiotelephone system (100). The active call is determined (601) to be in danger of being dropped responsive to the mobile station (119) suddenly transitioning from the first coverage area (121) to the second coverage area (122). The first base station (115) is notified (602) that the active call is in danger of being dropped responsive to the step of determining (601). The active call with the first base station (115) is determined (603) to be in the process of being dropped responsive to the step of notifying (602). The active call is established (604) with the second base station (116) in the second coverage area (122) before the active call with the first base station (115) is dropped responsive to the step of determining (603).
摘要:
A coherent reverse channel, a per-chip spreading function, orthogonal spreading functions and a time alignment of all traffic channels are implemented such that the main signal of each channel arrives at a base-station within a fraction of a chip of one another in accordance with the invention. With this, the orthogonality among all channels is maintained, and, when demodulated, all channels except the channel of interest provides a cross-correlation of substantially zero with respect to the remaining signals.