Abstract: The invention relates to a method of estimating the frequency offset of a packet of phase modulated symbols received with phase error, the method comprising: applying a phase correction to the symbols of the received packet for all possible pairs of frequency offset and phase offset; and selecting from said offset pairs, the pair which provides the most likely packet of corrected symbols, thereby determining the frequency offset of the received packet. Compared with known solutions, the invention makes it possible to reduce errors concerning estimated frequency. Advantageously, the method comprises a step of quantizing the possible phase corrections, thereby making it possible to reduce the complexity of the calculations to be performed, without degrading performance.

Abstract: A communications system includes a first and second modem coupled together via a communications link. The first modem has at least two user devices coupled thereto, and modulates data generated by the user devices on a plurality of tone carriers for transmission to the second modem. The first modem determines the number of user devices coupled to it. Based upon the number of user devices determined, the first modem divides the plurality of tone carriers into a number of subsets corresponding to the number of user devices based upon a predetermined criterion. The first modem then allocates a subset of tone carriers to a respective user device. In one embodiment, the usage rate of each user device is determined, and the tone carriers are reallocated to different subsets as a function of the usage rate of each respective user device.

Abstract: When carrying out directive reception using an adaptive array antenna apparatus, a plurality of diversity reception circuits which differ in communication environment follow-up performance are used for reception and the reception output with the best reception quality is selected. The environment follow-up performance of the other non-selected diversity reception circuits is dynamically changed, preferably every time a selection is made by a selector based on the environment follow-up performance of a selected diversity reception circuit.

Abstract: A digital broadcast program broadcast with a first network is transmitted to a second network. A tuner 41 selects digital broadcast signal having a predetermined transmission frequency and ECC decoder 43 obtains MPEG2 TS packet S3 as the digital broadcast data on the digital satellite broadcasting. An NIT detecting circuit 44 detects NIT from the MPEG2 TS packet S3 and a control unit 31 changes the NIT to obtain a table NITb applicable to CATV. A NIT substitution circuit 48 detects NIT from the MPEG2 TS packet S3 and substitutes table the NITb for the NIT to obtain MPEG2 TS packet S4 as the digital broadcast data on the CATV. Then, an error correct code is added to the MPEG2 TS packet S4 and the added packet S4 is modulated. Then, modulated one is frequency-converted to obtain digital broadcast signal BS-1 having a predetermined transmission frequency for the CATV.

Abstract: An MMSE linear detector is implemented using a variable step-size Griffiths' algorithm. The received signal is sampled and stored. The stored samples are multiplied with components of a spreading sequence to provide products that are summed to provide a first output. The stored samples are also multiplied with components of a weight vector to provide products that are summed to provide a second output. A computing unit uses the Griffiths' algorithm to iteratively compute the weight vector. Another computing unit computes the step-size for each successive iteration of the Griffiths' algorithm based on the first and second outputs.

Abstract: Methods and systems are provided for receiving a modulated signal including symbols representing both encoded and unencoded bits from a data (e.g., speech) frame where a received slot is first demodulated and the encoded bits are decoded. The decoded bits are then utilized to constrain demodulation during a second demodulation of a received slot. The encoded bit positions from the constrained second demodulation are, in turn, encoded to generate bit estimates for the received slot. This information is combined with the output of the constrained second demodulation for unencoded bits to provide a received data frame estimate which has been shown to have improved reliability for both encoded and unencoded bits. The methods and systems further provide for recursively repeating the demodulation and decoding steps until a counter expires or a desired reliability is obtained.