Airnet Communications Corporation

Other

Ronald R Carney

Terry L Williams

Thomas R Schmutz

Michael A Komara

John R Doner

Victor D Poor

A wireless system architecture whereby high efficiency broadband transceiver systems can be deployed at an initial build out stage of the system in a cost-efficient manner. A home base station location is identified within each cluster of cells and rather than deploy a complete suite of base station equipment at each of the cells in the cluster, inexpensive translator units are located in the outlying cells serviced by the home base station in which low traffic density is expected. The translators are connected to directional antennas arranged to point back to the home base station site. The translators are deployed in such a way which meshes with the eventually intended frequency reuse for the entire cluster of cells. The translator to base station radio links operate in-band that is, within the frequencies assigned to the service provider. The available frequency bands are divided into at least two sub-bands, with frequency translations ocurring entirely within a given sub-band.

Wireless system plan using in band-translators with diversity backhaul

A wireless communication system basestation making use of a wideband, multichannel digital transceiver having incorporated therein a time division multiple-access (TDM) bus for providing digital samples of a plurality of wireless communication channels, wherein the TDM bus is used as a cross-bar switch to permit dynamic allocation of modulator and demodulator signal processing resources. The invention allows various standards, even those having different channel bandwidths, to be serviced by the same basestation, with automatic redistributed of signal processing resources, eliminating the need to reconfigure the basestation when the loading of different types of wireless signaling traffic changes.

Wideband wireless base-station making use of time division

A wireless system architecture whereby high efficiency broadband transceiver systems can be deployed at an initial build out stage of the system in a cost-efficient manner. A home base station location is identified within each cluster of cells and rather than deploy a complete suite of base station equipment at each of the cells in the cluster, inexpensive translator units are located in the outlying cells serviced by the home base station in which low traffic density is expected. The translators are connected to directional antennas arranged to point back to the home base station site. The translators are deployed in such a way which meshes with the eventually intended frequency reuse for the entire cluster of cells. The translator to base station radio links operate in-band, that is, within the frequencies assigned to the service provider. For example, the available frequency bands are divided into at least two sub-bands, with a first sub-band is assigned for use as a home base station to translator base station communication link and a second sub band is assigned for use by the mobile station to translator communication link. If desired, a third sub-band can then be used for deployment of base transceiver systems in the conventional fashion where the base station equipment located at the center of a cell site communicates only with mobile stations located within that cell.

Cellular system plan using in band-translators to enable efficient

A wireless communication system basestation making use of a wideband, multichannel digital transceiver having incorporated therein a time division multiple-access (TDM) bus for providing digital samples of a plurality of wireless communication channels, wherein the time slot duration and frame rate of the TDM bus may be reconfigured. The invention allows various air interface standards, even those having different channel bandwidths, to be serviced by the same basestation, without having to install additional or different equipment, and by automatically redistributing signal processing resources, eliminating the need to reconfigure the basestation when different types of wireless signaling must be accommodated.

Wideband wireless base station making use of time division multiple

A distortion correction technique for use with a high power amplifier (HPA) in a multi-carrier radio signaling system such as a cellular base station. Distortion correction is implemented by making use of a broadband digital composite signal input to the high power amplifier as a reference signal in a form of intermediate frequency (IF) distortion correction circuit. A multichannel synthesizer provides the broadband composite signal to a broadband digital radio which in turn provides an input to the (HPA). A portion of the output signal from the HPA is fed back through a radio frequency (RF) and intermediate frequency (IF) down-conversion stage that uses the same IF and RF local oscillators that were used to generate the input signal to the HPA. This feedback signal is fed to a predistortion processor together with a version of the composite digital signal. The predistortion processor may perform a first crude amplitude correction procedure by finding a difference between the HPA feedback signal and the composite signal, to provide an offset to be loaded into a look-up table which is disposed between the broadband digital synthesizer and the broadband digital radio,. Subsequent precise correction and distortion correction procedures are performed using the offset value.

Multi-carrier high power amplifier using digital pre-distortion

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. On the transmit side, a transmit section contains a plurality of digital signal processors, respectively associated with respective ones of a plurality of incoming (voice/data) communication signals to be transmitted over respectively different frequency channels. Their processed (modulated, encoded) outputs are supplied to an inverse FFT combiner. The FFT combiner supplies a combined multichannel signal to a wideband transmitter which transmits a multiple frequency communication channel signal. Each of the channelizer and combiner may be implemented using overlap and add or polyphase filtering.

Transceiver apparatus employing wideband FFT channelizer and inverse FFT

A technique which enables the use of a low cost linear power amplifier to generate a wideband composite signal, such as in cellular mobile telephone (CMT), personal communication system (PCS), or other multi-channel wireless systems. A composite signal is generated by a wideband digital combiner as a frequency multiplexed combination of many narrowband modulated digital carrier signals. The technique involves introducing predetermined phase shifts into each of the digital channel signals after a baseband modulation step. The wideband composite signal thus exhibits a reduced peak-to-average signal power, despite the fact that the phases of the digital carrier signals cannot be directly controlled. This permits the use of a power amplifier, which may have a much smaller peak-to-average rating.

Reducing peak-to-average variance of a composite transmitted signal

A wireless communication system includes a plurality of wideband base stations and a cluster controller that dynamically controls channel allocations among the base stations. When a base station can not service a radio telephone terminal within its cell site, the base station polls the channels and sends a request for a channel to the controller, listing in the request the channels the station determines at the cell site to be inactive. The controller consults a load statistics table to determine if a first listed channel is free over the system. If so, the controller allocates the channel to the base station, if not the controller searches the table for a free channel. The controller may also include channel usage rates in the table. These rates indicate for a predetermined period of time for each base station the rate at which the base station assigns channels to the terminals and the number of channel in use simultaneously. The controller checks the channel usage rate associated with the base station to which the free channel is allocated to determine if the rate is below a predetermined maximum value. If so, the controller allocates the channel. Otherwise, the controller searches the table for a next free listed channel, and so forth. The controller may also preallocate channels to the base station based on expected use. To determine expected use, the controller accumulates the channel usage information over a number of predetermined periods of time and determines a pattern of use, if possible. The controller then, at appropriate times, i.e., when the pattern indicate changes in usage, preallocates channels from the base stations with low expected use to the base stations with high expected use.

System for dynamically allocating channels among base stations in a

Wideband wireless basestation making use of time division

A technique for extending the instantaneous dynamic range available in a wideband digital basestation for use in a wireless communication network. The basestation processes the bandwidth allocated to it in two or more sub-bands. The sub-bands are each processed by a digital tuner section consisting of an amplifier, analog-to-digital (A/D) converter, and digital filter bank. The digital filter bank may make use of multirate digital signal recovery techniques for efficient implementation. In operation, a received signal strength indication (RSSI) is first determined for each subscriber unit requesting access to the basestation. A channel assignment controller then assigns a transmit frequency to the subscriber unit depending upon this RSSI. In particular, subscriber units exhibiting a relatively stronger RSSI are to transmit on a frequency assigned to a first digital tuner section, while subscriber units having a relatively weak RSSI are assigned to a second digital tuner section. The gains of the first and second tuner sections of each other adjusted independently, to insure that the relatively strong signals are not clipped by the first tuner section, and that the relatively weak signals may be correctly detected by the second tuner section. The net effect is to provide a much greater overall system dynamic range. The invention can be used to advantage in both existing AMPS type cellular systems as well as CDMA systems.

Multichannel wideband digital receiver making use of multiple wideband

A physically compact, multichannel wireless communication transceiver architecture employs overlap and add or polyphase signal processing functionality, for wideband signal processing, together with a sample rate. 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. On the transmit side, a transmit section contains a plurality of digital signal processors, respectively associated with respective ones of a plurality of incoming (voice/data) communication signals to be transmitted over respectively different frequency channels. Their processed (modulated, encoded) outputs are supplied to an inverse FFT combiner. The FFT combiner supplies a combined multichannel signal to a wideband transmitter which transmits a multiple frequency communication channel signal. Each of the channelizer and combiner may be implemented using overlap and add or polyphase filtering.

Growing community of inventors

Palm Bay, FL, United States of America

Ronald R Carney