Abstract: A channelizer (16) and combiner (22) in a cellular-telephone base station (10) are implemented in fast-Fourier-transform butterfly circuits (FIG. 4 ) in which outputs of adders (40, 46) are applied to successive adders (46, 50) in bit alignment. Although this makes it necessary for the input to the first adder (40) to leave some of the adder's input-port bit width unused in order to avoid the carries that a bit-aligned architecture cannot accommodate, the resultant accuracy exceeds that of a bit-offset architecture, because it can take advantage of rounding (56, 58) applied to each fast-Fourier-transform pass's input operands.

Abstract: A technique for allocating frequencies in a cellular communication system. The frequency reuse plan divides all available frequencies into six groups with the frequencies assigned in an ascending index order modulo 6. A three cell reuse plan is implemented with six 60.degree. sectorized antennas per cell, and two frequency groups being assigned for use in each cell. The channel groups are allocated to the sectors such that no two adjacent sectors use the same frequency groups. As a result, an effective times one frequency reuse plan is implemented. A frequency assignment process which attempts to avoid assigning the same frequency to a mobile which is located in the outer portion of a sector which is also in use in potential interfering outer sectors of homologous cells insures that carrier to interference (C/I) ratio minimums can be met without specialized encoding techniques.

Abstract: In a cellular-telephone-system base-station receiver's channelizer (111), frequency translation of the outputs of a filter bank (FIG. 5) implemented in fast-Fourier-transform circuitry (453,455,460) is achieved by rotating the correspondence between FFT input elements and the filter coefficients by which multipliers (437) multiply incoming samples to produce them. Specifically, a storage-address generator (482) directs that corresponding FFT input elements of successive FFT operations be stored in the same locations in an input-data memory (451). To retrieve those values for use in the DFT operation, however, a fetch-address generator (484) employs a modulo-K adder (488) to impose a changing offset so that the starting address for retrieval of each FFT operation's input record changes between FFT operations by the filter bank's decimation rate M.

Abstract: A self-resetting status register has two flip-flops per status bit to provide a stable output signal while the register is being read and to recognize event signals that are applied to the register during the read operation.

Abstract: A physically compact, multichannel wireless communication transceiver architecture employs overlap and add or polyphase signal processing functionality, previously applied to narrowband speech analysis research, for wideband signal processing. A receiver section receives a plurality of multiple frequency communication channels and outputs digital signals representative of the contents of the plurality of multiple frequency communication channels. The receiver section contains an FFT-based channelizer that processes the digital signals output by a wideband digital receiver and couples respective channel outputs to a first plurality of digital signal processor units, which process (e.g. demodulate) respective ones of the digital channel signals and supply processed ones of the digital channel signals at respective output ports for distribution to an attendant voice/data network.

Abstract: A technique which enables the use of a low cost non-linear power amplifier to generate a wideband composite signal, such as in cellular mobile telephones (CMTs), personal communication systems (PCSs), and other multi-channel wireless system. A constant envelope signal is generated from a wideband composite signal comprised of a combination of many narrowband modulated signals. The technique involves adding one or more out-of-band artifact signals that accurately offset the amplitude variations of the wideband composite signal. The constant envelope signal is then fed to a high power amplifier, and, prior to radio transmission the amplified signal is filtered to remove the out-of-band artifact signals. As a result, only the desired composite signal having any required envelope variations is provided to the antenna, while at the same time, only a constant envelope signal is fed through the power amplifier.