Abstract:
Modulation codes for code division multiple access (CDMA) cellular communications systems that are mutually orthogonal may be generated as a sequence of Walsh codes. A method of assigning Walsh codes includes the steps of ( 404 ) receiving as input a status vector ( 200 ) for a Walsh code system of length 2 n and a selected Walsh code length j=2 n-k ; ( 406 )-( 418 ) creating a new status vector for a selected Walsh code length of j from the status vector; ( 416 ) creating a search mask for the selected Walsh code length j; ( 418 ) creating a search sequence for the selected Walsh code length j; and ( 434 )-( 442 ) searching the search sequence for the next available Walsh code. The status vector is updated ( 500 ) to track the assignment and release of each Walsh code of each Walsh code length in the Walsh code system.
Abstract:
Modulation codes for code division multiple access (CDMA) cellular communications systems that are mutually orthogonal may be generated as a sequence of Walsh codes. A method of assigning Walsh codes includes the steps of ( 404 ) receiving as input a status vector ( 200 ) for a Walsh code system of length 2 n and a selected Walsh code length j=2 n-k ; ( 406 )-( 418 ) creating a new status vector for a selected Walsh code length of j from the status vector; ( 416 ) creating a search mask for the selected Walsh code length j; ( 418 ) creating a search sequence for the selected Walsh code length j; and ( 434 )-( 442 ) searching the search sequence for the next available Walsh code. The status vector is updated ( 500 ) to track the assignment and release of each Walsh code of each Walsh code length in the Walsh code system.
Abstract:
Modulation codes for code division multiple access (CDMA) cellular communications systems that are mutually orthogonal may be generated as a sequence of Walsh codes. A method of assigning Walsh codes includes the steps of (404) receiving as input a status vector (200) for a Walsh code system of length 2n and a selected Walsh code length j = 2n-k; (406) - (418) creating a new status vector for a selected Walsh code length of j from the status vector; (416) creating a search mask for the selected Walsh code length j; (418) creating a search sequence for the selected Walsh code length j; and (434) - (442) searching the search sequence for the next available Walsh code. The status vector is updated (500) to track the assignment and release of each Walsh code of each Walsh code length in the Walsh code system.
Abstract:
A cellular communications system capable of detecting long code mask collisions in the reverse link on call setup or call handoff comprises means for assigning (120) a different carrier for the reverse link for one of the duplicate calls, for avoiding interference and dropped calls.
Abstract:
A plurality of base stations (600) are programmed (702) with a uniform power-control bit pattern to be sent to a mobile unit during a plurality of power-control bit times, before the mobile unit is acquired on a reverse link. The plurality of base stations are further arranged and programmed to synchronize (704) transmissions of the uniform power-control bit pattern such that the plurality of base stations, when transmitting, send identical power-control bits during each of the plurality of power-control bit times.
Abstract:
A plurality of base stations (600) are programmed (702) with a uniform power-control bit pattern to be sent to a mobile unit during a plurality of power-control bit times, before the mobile unit is acquired on a reverse link. The plurality of base stations are further arranged and programmed to synchronize (704) transmissions of the uniform power-control bit pattern such that the plurality of base stations, when transmitting, send identical power-control bits during each of the plurality of power-control bit times.
Abstract:
After a base station (101) receives a call origination message from a remote unit (113), the base station determines (101) those base stations (101-103) that are capable of supporting communication with the remote unit (113). The eligible base stations (eligible set) are instructed to "listen" for communication from the remote unit (113), and the remote unit (113) is provided the eligible set. Once the remote unit (113) receives the eligible set of base stations, the remote unit then determines the base station (103) having the best radio environment characteristics, and begins communication with the base station (103).
Abstract:
Wireless communication system (10) management has been provided with a filtering threshold (34) to trigger events to control handovers of mobile stations (12, 14). In a non-active set base station process, it is determined (106) whether a base station signal strength measurement in a non-active set of a mobile station is less than the filtering threshold (34). If not, the predefined event is executed (108). Otherwise, the signal strength measurement is ignored (112). For an active set base station process, it is determined (206) whether a signal strength measurement of a base station in the active set of the mobile station is less than the filtering threshold (34). If not, the signal strength measurement is compared (212) to an event threshold. The signal strength measurement of the base station is ignored (214) when the signal strength measurement is not less than the event threshold.
Abstract:
A mobile station typically determines whether to drop a communication link and/or a base transceiver station (BTS) based on a performance of an associated forward link. In order to avoid dropping a communication link (220) that has a weak forward link (222) but a strong reverse link (224), a communication system is provided that determines whether the reverse link is still good before determining to drop the communication link (220). In one embodiment, the communication system determines whether reverse link (224) is still good based on a quality metric associated with the reverse link and quality metric(s) associated with one or more other reverse links (234) that are in a soft-hand-off mode with reverse link. In another embodiment, the communication system determines whether reverse link (224) is still good by comparing a quality metric associated with the reverse link to a threshold.