Abstract:
A code-division-multiple-access (CDMA) system employing spread-spectrum modulation. The CDMA system has a base station, and a plurality of subscriber units. The signals transmitted between the base station and subscriber unit use spread-spectrum modulation. The system and method transmits from the base station, a synchronization channel having a chip-sequence signal used by the plurality of subscriber units for synchronization. A first subscriber unit receives the synchronization channel, and determines timing from the synchronization channel. In order to initiate communications with the base station, the first subscriber unit transmits an access signal. The access signal has a plurality of power levels, which typically ramp up. The base station receives the access signal at a particular-power level. The base station then transmits to the first subscriber unit an acknowledgment signal. The first subscriber unit receives the acknowledgment signal, and transmits to the base station, a spread-spectrum signal.
Abstract:
A base station for controlling transmission power during the establishment of a communication channel utilizes the reception of a short code during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional access code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The power of the short code is quickly increased until the signal is detected by the base station. Once the base station detects the short code, it transmits an indication that the short code has been detected.
Abstract:
A base station for controlling transmission power during the establishment of a communication channel utilizes the reception of a short code during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional access code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The power of the short code is quickly increased until the signal is detected by the base station. Once the base station detects the short code, it transmits an indication that the short code has been detected.
Abstract:
A terminal, in particular a mobile terminal, comprises means for processing a positioning signal coming from a satellite positioning system, means for computing direct and inverse Fourier transforms, wireless communication means using OFDM modulation, and priority management means for assigning resources of the direct/inverse Fourier transform computation means either to the positioning signal processing means or to the wireless communication means.
Abstract:
The present invention is related to a Rake receiver (R1) for receiving a radio signal and to a searcher (S8a, S8b) for estimating the delay profile of one or more radio links. The searcher includes means for estimating delay profiles in separate windows. The searcher is arranged for being switched into a single window mode or alternatively into a multiple window mode. In single window mode the delay profiles of separate radio links are estimated in the windows, while in multiple window mode two or more windows are allocated adjacent in time for estimating the delay profile of the same radio link. Thereby, the use of the resources of the searcher can be adapted to the radio environments in which the searcher will be used. The Rake receiver comprises fingers that are grouped into two sets. Within a set of fingers the propagation paths are time aligned. The output from the two set of fingers are time aligned and then combined.
Abstract:
A method of managing processing resources in a mobile radio system, in which a first entity manages radio resources and corresponding processing resources, the latter being provided in a second entity separate from the first entity. The second entity signals to the first entity its global processing capacity, or capacity credit, and the consumption law, or quantity of the global processing capacity, or cost, for different spreading factor values. The first entity updates the capacity credit on the basis of the consumption law. In the case of multicode transmission using N spreading codes, the updating is effected on the basis of the cost for at least one of the N spreading codes.
Abstract:
A method and apparatus for receiving a spread spectrum signal at a mobile communications terminal, including the step of processing the signal for the purposes of signal acquisition and signal tracking, monitoring movement of the mobile terminal and deriving a signal indicative of a characteristic of movement of the mobile terminal, and further including changing the mode of the processing of the incoming spectrum signal in response to the signal indicating the said characteristic of movement of the mobile terminal.
Abstract:
A WLAN transmitter capable of transmitting data signals modulated in accordance with an individual one of at least two different modulation schemes and corresponding methods and integrated circuit chips are provided. The WLAN transmitter contains a front end section having a low-IF topology and including a digital front end unit and an analog front end unit. The digital front end unit contains a first signal processing branch for processing transmission data signals modulated in accordance with a first one of said at least two different modulation schemes. The digital front end unit further contains a second signal processing branch for processing transmission data signals modulated in accordance with a second one of said at least two different modulation schemes. The analog front end unit contains one single signal processing branch for processing transmission data signals modulated in accordance with any one of said at least two different modulation schemes.
Abstract:
A system for rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system comprises a generator for generating a first long code and a second long code, with each long code having a length of N chips. The first long code is different from the second long code. A transmitter transmits the first long code and the second long code at a first phase angle and at a second phase angle, respectively, on a carrier signal over a communications channel using radio waves. The first long code and the second long code may be transmitted at an in-phase (I) angle and at a quadrature-phase (Q) angle, respectively, on the carrier signal. From the communications channel, an I acquisition circuit and a Q acquisition circuit may acquire, in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips of the first long code and the second long code.
Abstract:
A base station for controlling transmission power during the establishment of a communication channel utilizes the reception of a short code during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional access code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The power of the short code is quickly increased until the signal is detected by the base station. Once the base station detects the short code, it transmits an indication that the short code has been detected.