Abstract: There is provided a synchronization acquiring circuit for stably acquiring frame synchronization without pseudo-synchronization lock when the frame synchronization is acquired in reception at the time of a low C/N. The synchronization pattern of a received frame is detected by a frame synchronization detecting circuit 2. The bits of the synchronization pattern of the received frame are compared with those of a frame synchronization pattern on the transmitting side by a frame synchronizing circuit 5 to obtain the number of coincided bits. The frame synchronization is regarded as detected when the obtained number of bits of each frame is equal to or larger than the correlation detection value.

Abstract: A radio transmitter in which a power level of a modulated signal that has been amplified by an amplifier is detected, an error component is detected by comparing the detected power level with a theoretical value, an ideal value is calculated by adding the error component to the theoretical value, a reference level is generated by comparing the ideal value with the error component, and the gain of the amplifier is controlled based on a difference between the detected power level and the generated reference level.

Abstract: A transmission method and apparatus which perform communication without interfering with other types of communication is provided. A transmission symbol stream is generated by applying predetermined modulation processing to an encoded bit series obtained by encoding an information bit series of a predetermined transmission rate. A transmission signal generated by applying the transmission processing to the transmission symbol series is then transmitted. A transmission-information bit series with a transmission rate lower than the predetermined transmission rate is generated first. Transmission of the transmission signal generated in accordance with the transmission-information bit series then begins through a predetermine communication channel. The low transmission rate is then sequentially stepwise increased to the predetermined transmission rate.

Abstract: A GPS receiver having a fast time to lock to a GPS signal by storing a time period of an incoming GPS signal in a signal memory and rapidly comparing the signal memory against locations in a replica memory having stored GPS signal replicas. The GPS receiver includes a memory-based search engine for acquiring the GPS signal so that it may be tracked. The memory-based search engine includes a signal memory for storing a millisecond of a digitized GPS signal, a replica memory section for storing replicas representative of the digitized GPS signal for all possible frequency differences between the GPS carrier frequency and a local reference frequency and phase offsets between the GPS code phase and a local reference time, and a GPS memory comparator for comparing the stored signal in signal memory to the stored replicas in replica memory and issuing an acquisition detection signal when the level of the comparison is greater than a selected threshold.

Abstract: A method of coding parallel data for transmission while maintaining baud rate includes the steps of providing a plurality of uncoded data blocks having a predetermined baud rate, demultiplexing the data blocks to sequentially distribute the data blocks to encoders, encoding the data blocks at the predetermined baud rate, and serializing the coded data blocks for serially transmitting data at the predetermined baud rate. A system for coding parallel data for serial transmission while maintaining baud rate is included wherein the predetermined baud rate is maintained by providing an adequate number transmission links rather than increasing baud rate.

Abstract: A receiver, comprising an adaptive filter, performs blind equalization using a modified form of the constant modulus algorithm (CMA). This modified form of CMA is referred to as symbol CMA (SCMA). SCMA utilizes both the constant R and the sliced symbols, Ân, in performing blind equalization. The constant R is statistically created to the sliced symbols, Ân. The adaptive filter is a two-filter structure. The SCMA blind equalization technique reduces the rate of occurrence of a diagonal solution.

Abstract: A receiver, comprising an adaptive filter, performs blind equalization using a modified form of the constant modulus algorithm (CMA). This modified form of CMA is referred to as phase compensating CMA (PC-CMA). PC-CMA includes a phase-compensating term in the tap updating algorithm of the equalizer such that convergence to a straight constellation is achieved without the need of a rotator.

Abstract: A radio communication device provides extended burst tone detection for a demodulated I and Q input signal. The device includes a first burst detector coupled with the input signal and provides a first detection signal when a FCB tone is detected. A frequency shifter is coupled with the input signal and frequency translates the input signal by a predetermined amount. A second burst detector is coupled with the translated input signal and provides a second detection signal when a FCB tone is detected. A combiner is coupled with the first and second detection signals and indicates FCB tone detection when either of the first and second detection signals indicate FCB tone detection.

Abstract: The invention relates to a method for implementing a transmission connection. In accordance with the method, symbols (DATA_IN) are formed from the bit stream to be transmitted, carriers are generated on several different frequency bands, and the bit stream is transmitted with the aid of the carriers by dividing the formed symbols between the carriers in such a way that each carrier is modulated with some of the bits in the bit stream. To enable implementation of modulation and demodulation in such multicarrier systems with as simple and efficient equipment as possible, the modulated carriers are first generated on the transmitter side each separately on predetermined first frequencies, whereafter at least some of the carriers are supplied to a halfband filter bank (64) transferring at least some of the carriers supplied to it to their final frequency bands in the frequency domain and combining said carriers to its output. Halfband filter bank is also used in the receiver.

Abstract: An apparatus and method for communicating data between at least two data devices, suitable for use as a wireless local-area network, that provides robust data communication via a radio communications channel corrupted by multipath interference, particularly at high data rates. A preferred embodiment of the invention represents data as a sequence of Walsh-function waveforms encoded by pseudo-noise direct-sequence spread-spectrum modulation. Walsh-function-encoding of the data provides a long symbol duration, thereby allowing the spread-spectrum modulation to provide processing gain sufficient to substantially overcome multipath interference, while providing a high data rate. In another preferred embodiment, Walsh-function modulation is supplemented with various forms of phase modulation, such as coherent PSK for bi-orthogonal signalling, and DPSK between orthogonal symbols for noncoherent bi-orthogonal signalling, thereby further increasing data rate without reducing processing gain.

Abstract: The invention relates to a method for estimating the quality of a connection and a diversity combination method in a digital radio system in which the signals transmitted are in burst form, the bursts comprising a training sequence; and to a receiver comprising a filter matched to the received signal. To effect simple estimation of the quality of the connection, the receiver comprises means for forming a result vector of at most the length of the training sequence from the symbols of the output signal of the matched filter and the corresponding symbols of the training sequence; means for computing a mean value and variance for the symbols of the result vector; and means for forming a quantity proportional to signal quality as a quotient of the squared mean value of the result vector and the variance of the result vector.

Abstract: An arrangement where a transmitter has a plurality of transmitting antennas that concurrently transmit the same symbol, and where the signal delivered to each transmitting antenna is weighted by a factor that is related to the channel transmission coefficients found between the transmitting antenna and receiving antennas.

Abstract: The present invention makes it possible to transmit data while reducing the influence of fading caused on a transmission path. When communication data is transmitted by using a plurality of subcarriers arranged with a predetermined bandwidth, a data block consisting of a plurality of subcarriers arranged in rows in a time axis direction is used as a data unit. By implementing both a differential modulation process based on each phase difference in the frequency axis direction between a plurality of subcarriers and a differential modulation process based on each phase difference in the time axis direction between a plurality of subcarriers, a transmission signal with symbol data superposed on each phase difference between a plurality of subcarriers is generated and output.

Abstract: Disclosed are radio frequency (RF) interference cancellation techniques that effectively estimate RF interference to the data signals being received using a frequency domain model, and then remove the estimated RF interference from the received data signals. Improved techniques for digitally filtering multicarrier modulation samples to reduce sidelobe interference due to the RF interference are also disclosed.

Abstract: A system and method for signal peak reduction in a multiple carrier communication system where the individual carriers are produced from input symbols that are filtered to reduce individual carrier bandwidths, offset in frequency, and combined into an output signal. A multiple carrier peak reduction unit is provided which modifies the input carrier symbols so that the combined output signal does not exceed a predetermined peak limit value. The multiple carrier peak reduction unit includes filter predictors that predict the effect of each channel filter on that carriers input symbols by using filter coefficient values corresponding to the impulse response function of each filter. The filter predictor outputs are then phase shifted, in correspondence to frequency offsets provided for in multiple carrier signal generation, and combined to produce a prediction of the combined signal output which is then processed to determine the corrections required to the individual channel symbol inputs.

Abstract: A system and method for signal peak reduction in a spread spectrum communication system of the type including a filter for limiting signal bandwidth of symbols transmitted from the system. A signal peak reduction unit is provided before the filter that includes a filter predictor that predicts the effect of the filter on input symbols by using filter coefficient values corresponding to the filter impulse response function. Input symbols that are predicted to cause the output signal to exceed a predetermined peak limit value are adjusted. Several examples of suitable algorithms for calculating the necessary peak reduction to be applied to the input symbols are disclosed. The peak reduction unit provides adjusted symbols to the filter for processing and communication system output.

Abstract: A method for discrimination of repetitive sequences in a wireless communication system in which the repetitive sequences have the same repetition length. For the discrimination the repetitive sequences are modified by changing the phase of at least one of the sequences. The auto-correlation values of the repetition sequences and of the modified repetitive sequences are calculated and the auto-correlation signs of the repetition sequences and of the modified sequences are compared.

Abstract: The invention relates to a method for receiving a multicarrier signal, in particular for a single transmission of a data block. In which case a multicarrier test signal having a cyclic time layout is transmitted together with the data block, and the multicarrier test signal is used for combined measurement of a start of a first data symbol of a data block and of any carrier-frequency shift between a transmitter and a digital receiver. The digital receiver evaluates the multicarrier test signal by performing a sequence of test steps.

Abstract: An architecture for simplified automatic gain control circuit (100, 200, 300) that is useable with M-ary QAM systems to improve overall link performance. The implementations particularly relating to modulating an M-ary QAM constellation according to a set of estimates derived from the pilot channel(s) and/or the traffic channels, modulating the M-ary QAM constellation according to the values of the pilot and traffic channel gains that are being sent to a mobile wireless device on a control channel, and using a power control bit at the mobile wireless device to modulate the M-ary QAM constellation, all resulting in improved receiver performance.

Abstract: In a mobile radio communication system, a transmitter of a base station transmits broadcast information to receivers of mobile stations in the form of frames. The transmitter produces a long frame composed of a plurality of frames each including a first bit sequence and part of the broadcast information following the first bit sequence, and a second bit sequence located at the head of the long frame. Each of the first bit sequences and the second bit sequence is used for establishing synchronization between the transmitter and each of the receivers. Upon receipt of the long frame from the transmitter, the receiver establishes synchronization of the long frame based on the foregoing second bit sequence.