摘要:
A long code scrambler has been provided to scramble the data bits prior to QAM mapping. Different data rates are accommodated by using different long code m-tuples sampled at the modulation symbol rate, where m equals 2, 4 or 6 for 4, 16 or 64 QAM, respectively. In order to support 1XEV-DV users employing multiple Walsh code channels, a long code 6-tuple sample is permutated, to further randomize the QAM symbols. As appropriate for the modulation order, 2, 4 or 6 bits of the permutated 6-tuple are applied to the data sequence. That is, in addition to randomizing the modulation symbols for a given code channel, each code channel will likely have unique QAM symbols at any given symbol time.
摘要:
A method and apparatus for signal combining within a communication system is provided herein. The output of RAKE fingers is combined via a chip combiner. The combined chip stream can be despread with the appropriate Walsh code (defining a particular channel). The resulting symbol stream can then be deinterleaved and decoded.
摘要:
At the control apparatus which is at a location external to a vehicle, a communication link is established with a transponder at the vehicle. The vehicle is located in the immediate vicinity of the location. A continued presence of the vehicle in the vicinity of the location via the communication link is monitored.
摘要:
A method and apparatus for system time alignment is provided. The method and apparatus for a system time alignment provides synchronization between system components even when one or more system components remains in a quiescent mode for an extended period of time. Compensation for changes in propagation delay between system components is provided, even when such changes in propagation delay occur while one or more system components is in a quiescent mode. A searcher (402) searches a raw data signal for a maximal energy, and a shifter (403) shifts a spreading sequence a plurality of times. An accumulator (408) accumulates a plurality of sets of symbols to produce a plurality of symbol energies. A time offset calculator (410) calculates an updated time offset value and an updated system time value and updates a reference position counter (202) and a system time counter (205), respectively, with these values.
摘要:
At the control apparatus which is at a location external to a vehicle, a communication link is established with a transponder at the vehicle. The vehicle is located in the immediate vicinity of the location. A continued presence of the vehicle in the vicinity of the location via the communication link is monitored.
摘要:
An analog switch (100) isolates a microprocessor (120) from potentially damaging programming voltages input to a PROM (110). The microprocessor (120) controls the switch (100) to allow a lower, status voltage to be input to the microprocessor (120). When the PROM (110) is to be programmed, the microprocessor (120) opens the switch (100) to isolate the microprocessor (120) and allow the 12 VDC to only be coupled to the PROM (110).