A novel protocol for an ad-hoc, peer-to-peer radio network that provides collision-free channel access with an emphasis on improving geographic reuse of the frequency spectrum. The protocol of the invention is executed on the reservation or control channel, and provides a method for allocating data transactions on the data channels. The system of the invention utilizes multiple parallel data channels that are coordinated by a single reservation channel. The transceiver of the system employs two modems to solve the channel reliability issues with multiple channel designs, where one is dedicated as a receive-only modem for gathering channel usage information on the reservation channel. High quality voice, video and data may be transmitted. The reservation channel implements a time division multiple access algorithm with dynamic slot allocation. In a distributed manner, nodes determine geographic reuse of slots based on channel quality extracted from the modem. Signal quality calculations are used to determine the likelihood of a slot reuse causing destructive interference within a node's neighborhood. Requests for slot usage are compared with the known traffic pattern and accepted or rejected by nodes within RF signal range based on the signal quality calculations.

Time division protocol for an ad-hoc, peer-to-peer radio network having coordinating channel access to shared parallel data channels with separate reservation channel

An ad-hoc, peer-to-peer radio access system for cellular communications systems using time division duplex as a way of maximizing the bits/hz/km2 for cellular systems. The network architecture of the ad-hoc system allows the radio access to be integrated with the fixed components of a conventional cellular system, PSTN or ISP. The objective is to make the system of the invention transparent to the features and services provided by the external network. The advantages of such a system to a cellular operator are that significantly less infrastructure is required, and that the RF spectrum is more efficiently utilized resulting in much lower building and operating costs. The system architecture is comprised of remote terminals, routers, gateways, and at least one gateway controller that interfaces the ad-hoc system to a cellular network system. The ad-hoc system of the invention allows for both voice and data transmissions and receptions.

Ad hoc peer-to-peer mobile radio access system interfaced to the pstn and cellular networks

A personal communications system is described which includes components of software and hardware operating in conjunction with a personal computer. The user interface control software operates on a personal computer, preferably within the Microsoft Windows® environment. The software control system communicates with hardware components linked to the software through the personal computer serial communications port. The hardware components include telephone communication equipment, digital signal processors, and hardware to enable voice, fax and data communication with a remote site connected through a standard telephone line. The functions of the hardware components are controlled by control software operating within the hardware component and from the software components operating within the personal computer. The major functions of the system are a telephone function, a voice mail function, a fax manager function, a multi-media mail function, a show and tell function, a terminal function and an address book function. The telephone function allows the present system to operate, from the users perspective, as a conventional telephone using either hands-free, headset or handset operation. The telephone function is more sophisticated than a standard telephone in that the present system converts the voice into a digital signal which can be processed with echo cancellation, compressed, stored as digital data for later retrieval and transmitted as digital voice data concurrent with the transfer of digital information data.

Computer-based multifunction personal communications system.

One method for wirelessly determining a position of a mobile station includes measuring a round trip time (RTT) to a plurality of wireless access points, estimating a first distance to each wireless access point based upon the round trip time delay and an initial processing time associated with each wireless access point, estimating a second distance to each wireless access point based upon supplemental information, combining the first and second distance estimates to each wireless access point, and calculating the position based upon the combined distance estimates. Another method includes measuring a distance to each wireless access point based upon a wireless signal model, calculating a position of the mobile station based upon the measured distance, determining a computed distance to each wireless access point based upon the calculated position of the mobile station, updating the wireless signal model, and determining whether the wireless signal model has converged.

Wireless position determination using adjusted round trip time measurements

Improved methods and systems for position acquisition and/or monitoring are disclosed. The position acquisition and/or monitoring can be performed with improved intelligence so that data acquisition, transmission and/or processing is reduced. As a result, the position acquisition and/or monitoring is able to be performed in a power efficient manner.

Method and apparatus for intelligent acquisition of position information

A position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging signals is accurately determined to yield the range estimates required to calculate the position of the mobile radio. The master radio transmits ranging signals to plural reference radios which respond by transmitting reply ranging signals. Upon reception of the reply ranging signal, the master radio determines the range to the reference radio from the signal propagation time. Any combination of fixed or mobile radios having known positions can be used as the reference radios for another mobile radio in the system. Individual radios do not need to be synchronized to a common time reference, thereby eliminating the need for highly accurate system clocks. Errors in TOA estimates are minimized by performing internal delay calibration, Doppler compensation, leading-edge-of-the-signal curve fitting and frequency diversity techniques.

Method and apparatus for determining the position of a mobile communication device

Multirate wire line modem apparatus operable at either of two rates in either transmission or reception modes is provided according to the teachings of the instant invention. Full duplex operation and echo cancellation are utilized for both voice and data. Structurally an IOP processor acts as a system controller in controlling transmission and reception digital signal processors which provide the independent transmission and reception functions of the resulting multirate modem apparatus.

Multirate wire line modem apparatus

An echo cancellation apparatus is included in a variable rate modem. The echo cancellation apparatus includes a local echo canceler, a remote echo canceler and a quadrature echo canceler unit. The local and remote echo cancelers both operate to cancel echoes in a similar manner employing topped delay lines or transversal filters wherein the taps of each delay line are adjusted to accommodate both local and remote echo cancellation. The local echo canceler and the remote echo canceler share many programs in common. However, the remote echo canceler operates with a phase lock loop which essentially derives a signal obtained from the quadrature and local echo cancelers which signal is further correlated with the output residuals from the local echo canceler to develop samples applied to the remote echo canceler and to derive a frequency which is indicative of a offset carrier frequency to enable the remote echo canceler to cancel remote echoes. Remote echoes are due to frequency shifts occurring remote from the modem, such as those caused by changes in satellite positions or changes in frequency sources. The remote echo canceler operates to cancel echoes which are greater than 15 milliseconds in delay, as compared to local echoes, which are canceled by the local echo canceler responding to echoes which are delayed 15 milliseconds or less.

Local and remote echo canceling apparatus particularly adapted for use in a full duplex modem

A modulator/demodulator apparatus has a first digital signal processor (DSP1) that is operable in a full duplex mode for providing digital samples to a coder-decoder (IOP) and receiving transmitted samples therefrom. The first digital signal processor (DSP1) is responsive to received samples for initiating echo cancellation in the received samples. A second digital signal processor (DSP2) is operable to demodulate samples received from the first digital signal processor and output demodulated information therefrom. An input/output processor (IOP) initiates operation of the first and second digital signal processor. The input/output processor receives input information to be transmitted and supplies that information to the first digital signal processor and receives demodulated message information from the second digital signal processor and outputs message information to one or more user devices. The input/output processor also receives transmitter digital samples which are to be demodulated from the first digital signal processor and supplies the transmitted samples to be demodulated to the second digital signal processor. The input/output processor as operable in a full duplex mode. Accordingly the input/output processor acts as a system controller in controlling transmission and reception digital signal processors which provide independent transmission and reception functions suitable for a multirate modem apparatus.

Modulator/demodulator apparatus

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Papers

Method and apparatus for determining the position of a mobile communication device

Multirate wire line modem apparatus

Local and remote echo canceling apparatus particularly adapted for use in a full duplex modem

Modulator/demodulator apparatus