Abstract: A system and method providing a frame structure to received channel data sent over an air interface of a wireless communication system. The system and method may allow compensation for transmitting and receiving frequency variations, synchronization at the receiver, and provides a virtual signaling channel which may be used for system alarms and status. In one embodiment, the system uses bit stuffing, a frame preamble and a signaling preamble to transmit data at a high data rate in the ISM band.

Abstract: A system and method of frame synchronization and detection for use in a digital receiver within a communication system. The digital radio communication system includes a receiver for receiving a signal stream that includes data frames. Each frame includes an arbitrary data sequence and a unique word. A predetermined number of contiguous bits from the unique word are appended to the beginning of each data frame to identify the start of the data frame. The communication system comprises a sampling circuit for sampling symbol levels, a filter to implement the cross correlation of the received signal with the stored unique word, a threshold detector circuit to detect when frame synchronization is achieved as well as additional circuitry to refine the estimate from the threshold detection circuit. The design utilizes coherent demodulation. However, the design is equally applicable to non-coherent demodulation. In one embodiment, the sampling rate is assumed to be two samples per symbol.

Abstract: A system and method of timing estimation for use in a digital receiver within a communication system. An algorithm calculates the timing offset by evaluating the spectral component at the symbol clock frequency. The spectral component is generated using a nonlinearity operation. However, the maximum likelihood non-data-aided timing estimation equation reveals an alternative approximation for the logarithm of the hyperbolic cosine function present in the maximum likelihood equation, which offers a compromise between implementation complexity and variance performance. The estimated timing offset is then fed to a timing correction unit, which calculates the data samples corresponding to the sampling clock phase and removes the redundant samples. The ideal sampled signal is then forwarded to additional synchronization and functional units for further processing.

Abstract: A system and method for converting carrier frequencies of a wireless communication system is provided. The system and method allow expansion of coverage areas of wireless communication systems, such as a mobile/cellular telephone system. In one embodiment, the system converts RF signals in the PCS band to ISM band, and transmits the ISM signals to a distant repeater station. The repeater station receives the ISM signals and down converts the ISM signals to the PCS band. The PCS signals are retransmitted in a new cell thereby creating a new coverage area. Radio frequency signals are down converted to an Intermediate frequency for channel selectivity and narrow band filtering. Channel selectivity circuitry allows quick reuse of other channels in the same cell. The channel selectivity circuitry includes a SAW filter which significantly reduces out of band interference.

Abstract: A receiver for receiving a signal stream in a digital radio communication system. The signal stream includes data frames where each frame including a data signal sequence and a synchronizing signal sequence. The communication system synchronizes the receiver by employing the signal stream. The receiver includes a sampling circuit for sampling symbol levels in the synchronizing signal sequence and a synchronization subsystem. The synchronization subsystem utilizes a frame synchronization circuit, a dynamic interpolator and a decision-directed phase tracking mechanism for removing residual frequency and phase offsets. The synchronization subsystem also includes a threshold detection mechanism for comparing values derived from the sampled frame synchronization output with a predefined value which determines whether synchronization has occurred or not.

Abstract: A combiner circuit and method for use in a digital transmitter within a communication system. The combiner circuit receives a number of signal streams that include data frames. Each frame includes an arbitrary data sequence and portions of a unique word. The combiner circuit comprises a plurality of digital preamble circuits which append a predetermined number of contiguous bits from the unique word to each data frame. The system utilizes a plurality of spreaders, shifters, and a summer to further modify the data stream for transmission.

Abstract: A system and method for converting carrier frequencies of a wireless communication system is provided. The system and method allow expansion of coverage areas of wireless communication systems, such as a mobile/cellular telephone system. In one embodiment, the system converts RF signals in the PCS band to ISM band, and transmits the ISM signals to a distant repeater station. The repeater station receives the ISM signals and downconverts the ISM signals to the PCS band. The PCS signals are retransmitted in a new cell thereby creating a new coverage area.

Abstract: A system and method of buffering data of a wireless communication system. The system and method maintain synchronization, end-to-end signaling and coding overhead bits needed to encapsulate data frames sent over wireless media. Additionally, the system and method compensate for transmitting and receiving clock variations. In one embodiment, the system uses framing of data with preamble, stuffing and signaling bits transmitted synchronously at a high data rate in the Industrial, Scientific and Medical (ISM) bands.

Abstract: The present invention provides a system and method of timing estimation for use in a digital, receiver within a communication system. This method exploits the complementary information available from the use of two different nonlinearities to estimate the timing offset following asynchronous sampling of the received signal at a rate of two samples per symbol. The present method operates in a feedforward configuration thereby avoiding issues associated with feedback configurations such as hangup. The present method uses a magnitude square nonlinearity as well as a delay, complex conjugate and multiply nonlinearity to calculate the timing offset. The choice of these nonlinearities is influenced by the need for the estimator to operate in the presence of a phase offset on the received signal. Timing estimators which can tolerate the presence of a slowly varying phase offset over the observation interval on the received signal are especially important in all-digital feedforward receiver design.

Abstract: A system and method for communication of radio frequency (RF) signals over multimedia signal paths. The invention provides a wireless multimedia carrier (WMC) system capable of receiving a variety of standardized input signals, such as DS0/E0, T1/E1, T2/E2, and/or T3/E3 for transmission using RF channels. The WMC system selectively employs time division multiple access (TDMA) and/or code division multiple access (CDMA) technology. The WMC system transmits the various signal inputs using RF carriers, receives the transmitted signals, and converts the signals to the desired signaling scheme (standard) for forwarding to intended destinations.

Abstract: A system and method providing a structure to the data sent over the air interface of a wireless communication system. The system and method allow compensation for transmitting and receiving frequency variations, synchronization at the receiver and provision of a virtual signaling channel for system alarms and status. In one embodiment, the system uses bit stuffing, a frame preamble and a signaling preamble to transmit data at a high data rate in the ISM band.

Abstract: A system and method of buffering data of a wireless communication system. The system and method maintain synchronization, end-to-end signaling and coding overhead bits needed to encapsulate data frames sent over wireless media. Additionally, the system and method compensate for transmitting and receiving clock variations. In one embodiment, the system uses framing of data with preamble, stuffing and signaling bits transmitted synchronously at a high data rate in the Industrial, Scientific and Medical (ISM) bands.