Ericsson Gmbh

Ericsson Ge Mobile Communications Inc.

R David Koilpillai

Gregory Edward Bottomley

Rajaram Ramesh

Alex Krister Raith

Havish Koorapaty

Nils Rutger Rydbeck

Ali S Khayrallah

Jiann-Ching Guey

Sandeep Chennakeshu

Karl James Molnar

Tracy Lawrence Fulghum

Barbara Davis Molnar

Paul W Dent

Kumar Balachandran

Essam Abdelfattah Sourour

Jyun-Cheng Chen

Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention provide techniques which provide for interaction between an adjunct system whose primary function is to provide terminal unit location information and the radiocommunication system. For example, the location information generated by the adjunct system can be used by the radiocommunication system for other purposes, e.g., dynamic channel allocation.

Interaction between an adjunct positioning system and a radiocommunication system

A detector selector and method are provided for selecting among detectors, where a less complex detector detects known symbols in a received signal, and a bit error rate for the known symbols is used to determine whether the less complex detection method is sufficient. If the less complex detector is not sufficient, a more complex detector is used to detect the signal. Additionally, assured symbols are used as known symbols to increase the accuracy for the determination of whether the less complex detector is sufficient.

Signal detector selector and method for selecting a detector

A receiver in a communications system is operated by receiving a radio communications signal transmitted by a station of the communications system and generating a correlation output representing a correlation of the received radio communications signal and a subsequence of a modulation sequence that is selected based on a correlation between the selected subsequence and the modulation sequence. The receiver is then synchronized based on the generated correlation output. The selected subsequence preferably has an optimal out-of-phase correlation with the modulation sequence. According to an aspect of the present invention, the selected subsequence has a minimum out of phase correlation with the modulation sequence in comparison to other subsequences of the modulation sequence. For example, the selected subsequence may have a &ldquo;minimum maximum&rdquo; out-of-phase correlation value, a &ldquo;minimum aggregate&rdquo; out-of-phase correlation metric, or a combination thereof.

Modulation sequence synchronization methods and apparatus employing partial sequence correlation

Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Independent or quasi-independent systems, sometimes referred to as adjunct systems, can be provided to monitor remote unit transmissions and derive location information for mobile units making emergency access therefrom. Techniques for determining which channels each adjunct receive shall monitor are described herein, as well as specific monitoring techniques. Moreover, the adjunct system can use the received information to provide a second speech path to an emergency service center.

Systems and methods for locating remote units operating in a radiocommunication system using an adjunct system

Techniques for adapting detection schemes used in receivers for receiving radio signals are described. The received signal is processed to determine, for example, an amount of time dispersion present in the radio channel. Based on this determination an appropriate detection scheme is selected for detecting the transmitted symbols. Various techniques for determining the dispersive or non-dispersive nature of the channel are described.

System and methods for selecting an appropriate detection technique in a radiocommunication system

A message, e.g., a control message, a short message, a voice message or a data message, is transmitted on at least one of a first communications channel having a first redundancy level or a second communications channel having a second, higher redundancy level. A radio communications signal is received on one of the first communications channel and the second communications channel. The received radio communications signal is demodulated to recover the message using a first demodulation scheme if the radio communications signal is received on the first communications channel and using a second demodulation scheme if the radio communications signal is received on the second communications channel. According to an aspect of the invention, the received radio communications signal is coherently demodulated if the radio communications signal is received over the first communications channel and non-coherently demodulated if the radio communications signal is received over the second communications channel. According to another aspect, the message is transmitted on the first communications channel using a first modulation constellation, and transmitted on the second communications channel using a second modulation constellation representing a subset of the first modulation constellation. In other embodiments of the present invention, a first radio communications signal is transmitted representing the message encoded according to one of a first code or a second code that represents a concatenation of the first code and an additional code, such as an orthogonal code or a quasi orthogonal code. Related systems and apparatus are also described.

Apparatus and methods for providing high-penetration messaging in wireless communications systems

A digital subscriber loop (DSL) modem and methods for controlling a DSL modem are provided which support simultaneous voice and data communications, wherein the voice communication is provided in a first frequency range and the data communication is provided in a second, non-overlapping frequency range. A voice communication is detected in the first frequency range and the output power associated with the data communication in the second frequency range is reduced when a voice communication in the first frequency range is detected. Furthermore, the coding level associated with the data communication in the second frequency range may be increased when a voice communication in the first frequency range is detected. Also, the start frequency associated with data communication in the second frequency range may be increased when a voice communication in the first frequency range is detected.

Splitter-less digital subscriber loop modems with improved throughput and voice and data separation

In a wireless communications system, information is communicated over one of a first communications channel having a first redundancy level or a second communications channel having a second redundancy level based on a determination of communications quality for at least one of the channels. In embodiments of the present invention, communications occur over a first channel, e.g., a &ldquo;standard&rdquo; channel until a measure of communications quality for that channel, such as bit error rate or frame error rate, meets a predetermined criterion. When the communications quality meets the predetermined criterion, communications shifts to a &ldquo;robust&rdquo; high-penetration channel that utilizes substantially the same amount of spectral resource as the first channel but provides significantly increased redundancy. In other embodiments, a terminal, e.g., a cellular radiotelephone or other radio terminal, registers with a wireless communications system via one of a standard broadcast control channel or a high-penetration broadcast control channel, and switches therebetween based upon a determination of communications quality for the standard broadcast control channel. For example, the terminal may switch to the high-penetration broadcast control channel upon failure to acquire the standard broadcast control channel in a disadvantaged reception area.

Wireless communications systems with standard and robust services and methods of operation thereof

Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention provide improved techniques for using a system of monitoring or adjunct stations to provide this location information to the emergency service centers. For example, received signal strength measurements in conjunction with path loss models, alone or in conjunction with either time of arrival (TOA) or time difference of arrival (TDOA) techniques can be selectively used to process received signals and provide location information. Techniques for improving timing estimates are also disclosed.

Systems and methods for locating remote terminals in radiocommunication systems

In a transmitter for transmitting communication signals across a radio channel, an improved encoder includes a half-rate encoder receiving a digitized speech signal and generating a compressed bit stream at half-rate, and a signal expander receiving the compressed bit stream and generating an expanded bit stream at full-rate for transmission across a radio channel. An improved receiver, receives the transmitted communication signal which is selected from the group consisting of (a) a conventional full-rate encoded digitized speech signal, and (b) a half-rate encoded digitized speech signal including the expanded bit stream. The improved receiver includes a full-rate equalizer, a half-rate equalizer, and a switch initially routing the received digitized speech signal to the full-rate equalizer, wherein the full-rate equalizer demodulates the received digitized speech signal producing a full-rate demodulated signal and dibits of soft information corresponding to the full-rate demodulated signal. An analyzer analyzes the dibits of soft information and controls the switch to route the received digitized speech signal to one of the full-rate and half-rate equalizers based upon the analysis.

High-performance half-rate encoding apparatus and method for a TDM system

Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention facilitate the provision of this information by reducing a number of monitoring stations needed to track terminal location based upon control channel access. First, mobile units placing emergency calls can be forced to used designated control channels which may differ from control channels to which they are currently listening. Second, mobile units may be required to transmit at greater than specified power levels so that monitoring stations receive their emergency call access.

Systems and methods for handling emergency calls in hierarchical cell

Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention provide improved techniques for using a system of monitoring or adjunct stations to provide this location information to the emergency service centers. For example, either time of arrival (TOA) or time difference of arrival (TDOA) techniques can be selectively used to process received signals and provide location information. Techniques for improving timing estimates are also disclosed.

Systems and methods for locating remote terminals in radiocommunication

A radio receiver for demodulating and equalizing digital information is disclosed. The receiver receives radio signals and processes the signals to produce data samples which are then stored. Reference values that model what the receiver should receive for various transmitted symbol sequence hypotheses are also stored. The receiver equalizes the received data using the stored reference values to produce symbol detection information, and updates the reference values based on the symbol detection information.

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Apex, NC, United States of America

R David Koilpillai