A Code Division Multiple Access (CDMA) communication system which allocates different sets of frequencies to cells with different transmission power levels. Based upon the transmission power levels of a base station for each cell, each base station is assigned to one of at least two groups of base stations. Each group of base stations is assigned a set of frequencies for traffic communication. The set of frequencies assigned to one group of base stations does not overlap with the set of frequencies assigned to a different group of base stations.
A system and method for improving the accuracy of a location estimation measurement within a telecommunication system is disclosed. During a cessation of transmissions by a local base transceiver system in communication with the mobile station, the mobile station communicates with other, more remote base transceiver systems and trilateration and other distance measuring techniques are employed to calculate the position of the mobile station in relation to those remote base transceiver systems. In another embodiment of the present invention, the local base transceiver system is also used to calculate the position. In still another embodiment, during a cessation of transmissions by the mobile stations in communication with a local base transceiver system, the local base transceiver system is better able to use remote mobile stations for trilateration.
A technique for packet-switching suitable for interference-limited wireless communication systems is provided. Long bursty packets of data are broken into shorter units or packet-slots. This advantageously provides for averaging and minimizing interference in time--one of the requirements for achieving high system capacity in interference-limited systems. Transmit-start times and durations of packet slots are controlled by packet-slot distribution patterns. The patterns are representable by unipolar binary codes/sequences whose properties are based on number-theoretic principles. The technique minimizes the time variance of composite interference due to simultaneous transmissions of numerous signals over the same frequency channel. By minimizing the variance of overall interference, this technique satisfies the demand of multi-media traffic and also increases system capacity in a fading multipath environment.
A method and apparatus for detecting a pilot signal on a second frequency while monitoring a first frequency having an assigned paging slot and a plurality of non-assigned paging slots. The method comprises the steps of monitoring the assigned paging slot of the first frequency and scanning for the pilot signal on the second frequency during at least one of the non-assigned paging slots of the first frequency. If the pilot signal is detected while scanning the second frequency, the pilot signal is processed normally. The method also includes entering a sleep mode for a remainder of the non-assigned paging slots. In a preferred embodiment, scanning for the pilot signal on the second frequency occurs in a non-assigned paging slot immediately following the assigned paging slot. In an alternate embodiment, scanning for the pilot signal occurs in a non-assigned paging slot immediately preceding the assigned paging slot.
In a telecommunications network that employs a CDMA scheme, the amplitude associated with each independent CDMA carrier is digitally limited, thereby limiting the peak-to-average power ratio. This, in turn, is accomplished by measuring the instantaneous amplitude for the in-phase and quadrature signals that make up each CDMA carrier, deriving a maximum amplitude based on the instantaneous amplitude measurements, and then deriving one or more scaling factors based, in-part, on maximum amplitude. The one or more scaling factors are then applied to the in-phase and quadrature signals, which are subsequently filtered, combined and modulated by a corresponding CDMA carrier frequency.
An antenna unit equipped with a satellite radio tuner and a tuner-unequipped head unit are connected to each other through a serial bus cable. Equipped in the antenna unit, the satellite radio tuner has a tuner portion, a digital demodulating portion, an interface portion, and a CPU. The interface portion serves as a speech/serial converting portion for converting a digital speech signal into a serial signal. The head unit includes an interface portion for receiving the serial signal sent from the antenna unit through a serial bus cable. The interface portion serves as a serial/speech converting portion for converting the received serial signal into the speech signal.
