Abstract: An OFDM system embeds sequence information in the transmitted signal that reduces peak average power ratio (PAP) with minimal impact on the overall system efficiency. A marker is embedded onto the transmitted information that is used to identify the combining (inversion) sequence at the receiver. In one embodiment, selected tones in a cluster are rotated when the corresponding phase factor rotates the cluster.

Abstract: An efficient method for providing both dedicated and simulcast services over a common wireless infrastructure is described. The services can be terminal as well as to a multiplicity of terminals simultaneously. The method uses time division multiplexing and orthogonal frequency division multiple access for simulcasting information and transmitting dedicated message information from a plurality of base stations forming a cellular pattern over the same wireless frequency channel. The method comprises the steps of constructing frames for transmission by the plurality of base stations comprising control information, simulcast information and dedicated message information within predetermined time slots of the frames and allocating the simulcast information and the dedicated message information to time slots of the same frame predetermined by the control information of the frame. The underlying modulation technology used is OFDM and thereby the channel delay-dispersion is minimized.

Abstract: A MIMO OFDM system includes a plurality of space-time encoders for encoding respective data blocks with independent space-time codes. The transformed data block signals are transmitted by a plurality of transmit antennas and received by a plurality of receive antennas. The received data is pre-whitened prior to maximum likelihood detection. In one embodiment, successive interference cancellation can be used to improve system performance. Channel parameter estimation can be enhanced by weighting the channel impulse response estimates based upon a deviation from average.

Abstract: A rate-adaptive method of communicating over a multipath wireless communication system uses multiple links such that each end of a link uses multiple transmit and receive antennas. A number of independent streams that are to be transmitted for each link is determined based on an overall system performance measure. In addition, the system may also jointly determine the best modulation, coding, power control, and frequency assignment for each link, based on an overall system performance measure. In OFDM systems, the number of independent streams, as well as the modulation, coding, and power control, may be determined on a tone-by-tone basis based on an overall system performance measure.

Abstract: A method of locating a mobile telephone includes steps of receiving, transmitting, increasing and determining. In the receiving step, a first base station receives a call from a mobile telephone, the call including a dialed number and a TDMA signal. In the transmitting step, the base station transmits a control message to the mobile telephone when the dialed number meets a predetermined criterion, such as being 911. The control message instructs the mobile telephone to transmit the TDMA signal at a maximum power. In the increasing step, the mobile telephone increases the TDMA signal to maximum power in response to the control message. Then in the determining step, location information for the mobile telephone is determined based on at least one characteristic of the TDMA signal received at at least one of the first base station and other base stations.

Abstract: An OFDM system embeds sequence information in the transmitted signal that reduces peak average power ratio (PAP) with minimal impact on the overall system efficiency. A marker is embedded onto the transmitted information that is used to identify the combining (inversion) sequence at the receiver. In one embodiment, selected tones in a cluster are rotated when the corresponding phase factor rotates the cluster.

Abstract: An efficient method for providing both dedicated and simulcast services over a common wireless infrastructure is described. The services can be available to a single terminal as well as to a multiplicity of terminals simultaneously. The method uses time division multiplexing and orthogonal frequency division multiple access for simulcasting information and transmitting dedicated message information from a plurality of base stations forming a cellular pattern over the same wireless frequency channel. The method comprises the steps of constructing frames for transmission by the plurality of base stations comprising control information, simulcast information and dedicated message information within predetermined time slots of the frames and allocating the simulcast information and the dedicated message information to time slots of the same frame predetermined by the control information of the frame. The underlying modulation technology used is OFDM and thereby the channel delay-dispersion is minimized.

Abstract: Proposed is a method for reducing interference in a frequency hopping wireless communications system. In one embodiment of the present invention, a base station and a terminal station each using an orthogonal frequency division multiplexing (OFDM) technique to simultaneously measure an interference level for each system frequency and to enable high speed frequency hop pattern changes which can follow changes in desired and interfering signal levels due to changes in co-channel interference or shadow fading. The terminal station interference level measurement values are then transmitted to the base station. Next, the base station identifies each frequency hop pattern currently in use by each terminal station communicating with that base station.

Abstract: An improved OFDM receiver is realized by employing a simplified delay function for the transmissions channel. The simplified delay function yields a simplified frequency-domain correlation that is applied to develop an Eigen matrix U that is used in developing estimates of the channels. Those channel estimates are used in the receiver to develop the output signals.

Abstract: An improved OFDM receiver is realized by employing a simplified delay function for the transmissions channel. The simplified delay function yields a simplified frequency-domain correlation that is applied to develop an Eigen matrix U that is used in developing estimates of the channels. Those channel estimates are used in the receiver to develop the output signals.

Abstract: An efficient method for providing both dedicated and simulcast services over a common wireless infrastructure is described. The services can be available to a single terminal as well as to a multiplicity of terminals simultaneously. The method uses time division multiplexing and orthogonal frequency division multiple access for simulcasting information and transmitting dedicated message information from a plurality of base stations forming a cellular pattern over the same wireless frequency channel. The method comprises the steps of constructing frames for transmission by the plurality of base stations comprising control information, simulcast information and dedicated message information within predetermined time slots of the frames and allocating the simulcast information and the dedicated message information to time slots of the same frame predetermined by the control information of the frame. The underlying modulation technology used is OFDM and thereby the channel delay-dispersion is minimized.

Abstract: A TDMA wireless communication system adjusts the power control target and transmission power based upon link quality to enhance voice capacity. The power can be adjusted in response to the average SNIR and number of decoding errors in a link quality reporting period. The power control target can be increased and decreased in discrete intervals after evaluating the number of decoding errors in the reporting period. The transmission power can be adjusted towards the new power control target based upon the average SNIR.

Abstract: A method of locating a mobile telephone includes steps of receiving, transmitting, increasing and determining. In the receiving step, a first base station receives a call from a mobile telephone, the call including a dialed number and a TDMA signal. In the transmitting step, the base station transmits a control message to the mobile telephone when the dialed number meets a predetermined criterion, such as being 911. The control message instructs the mobile telephone to transmit the TDMA signal at a maximum power. In the increasing step, the mobile telephone increases the TDMA signal to maximum power in response to the control message. Then in the determining step, location information for the mobile telephone is determined based on at least one characteristic of the TDMA signal received at at least one of the first base station and other base stations.

Abstract: A TDMA wireless communication system adjusts the power control target and transmission power based upon link quality to enhance voice capacity. The power can be adjusted in response to the average SNIR and number of decoding errors in a link quality reporting period. The power control target can be increased and decreased in discrete intervals after evaluating the number of decoding errors in the reporting period. The transmission power can be adjusted towards the new power control target based upon the average SNIR.

Abstract: The present invention provides a method and system for reducing the peak to average power ratio (PAP) of a signal with low computational complexity. According to one embodiment, the present invention is applied to reduce the PAP of an OFDM signal. According to an alternative embodiment, the present invention is applied to reduce the PAP of a CDMA signal. Rather than seeking the optimum solution, which involves significant computational complexity, the present invention provides for a number of sub-optimal techniques for reducing the PAP of an OFDM signal but with much lower computational complexity. In particular, according to one embodiment utilizing the PTS approach, an iterative technique is used to assign phase factors to each of a set of partial transmit sequences from a set of possible phase factors. Experimental results using the iterative technique showed only a slight degradation (1 dB) from the optimal approach using the same number of subblocks and subcarriers.

Abstract: A method of locating a mobile telephone includes steps of receiving, transmitting, increasing and determining. In the receiving step, a first base station receives a call from a mobile telephone, the call including a dialed number and a TDMA signal. In the transmitting step, the base station transmits a control message to the mobile telephone when the dialed number meets a predetermined criterion, such as being 911. The control message instructs the mobile telephone to transmit the TDMA signal at a maximum power. In the increasing step, the mobile telephone increases the TDMA signal to maximum power in response to the control message. Then in the determining step, location information for the mobile telephone is determined based on at least one characteristic of the TDMA signal received at at least one of the first base station and other base stations.

Abstract: Proposed is a method for reducing interference in a frequency hopping wireless communications system. In one embodiment of the present invention, a base station and a terminal station each using an orthogonal frequency division multiplexing (OFDM) technique to simultaneously measure an interference level for each system frequency and to enable high speed frequency hop pattern changes which can follow changes in desired and interfering signal levels due to changes in co-channel interference or shadow fading. The terminal station interference level measurement values are then transmitted to the base station. Next, the base station identifies each frequency hop pattern currently in use by each terminal station communicating with that base station.

Abstract: The present invention provides a method and system for reducing the peak to average power ratio (PAP) of a signal with low computational complexity. According to one embodiment, the present invention is applied to reduce the PAP of an OFDM signal. According to an alternative embodiment, the present invention is applied to reduce the PAP of a CDMA signal. Rather than seeking the optimum solution, which involves significant computational complexity, the present invention provides for a number of sub-optimal techniques for reducing the PAP of an OFDM signal but with much lower computational complexity. In particular, according to one embodiment utilizing the PTS approach, an iterative technique is used to assign phase factors to each of a set of partial transmit sequences from a set of possible phase factors. Experimental results using the iterative technique showed only a slight degradation (1 dB) from the optimal approach using the same number of subblocks and subcarriers.

Abstract: Proposed is a method and apparatus for reducing interference in a frequency hopping wireless communications system. In one embodiment of the present invention, a base station and a terminal station each using an orthogonal frequency division multiplexing (OFDM) technique to simultaneously measure an interference level for each system frequency and to enable high speed frequency hop pattern changes which can follow changes in desired and interfering signal levels due to changes in co-channel interference or shadow fading. The terminal station interference level measurement values are then transmitted to the base station. Next, the base station identifies each frequency hop pattern currently in use by each terminal station communicating with that base station.

Abstract: This invention provides wireless resource allocation techniques where the wireless network resource allocation is based on maximum system gain. System gain may be the difference between a maximum performance (e.g., throughput rate) for a requested link and a performance loss of all currently active links affected by the requested link. A currently active link is affected if the requested link is within its link neighborhood. Wireless network resources are allocated to optimize system performance. Inter-base communication may be used to facilitate information exchange among base stations to optimize system performance. The performance loss experienced by any currently active link is called damage to that link. Damage may be determined in a pair-wise fashion based on a nominal performance which may be defined as the performance of a link if interference is experienced only from links which are outside the link neighborhood of the link or as a system parameter.