In many cellular systems, reusing spectrum bandwidth, creates problems in boundary regions between the cells and sectors where the signal strength received from adjacent base stations or adjacent sector transmissions of a single base station may be nearly equivalent. The invention creates a new type of diversity, referred to as multiple carrier diversity by utilizing multiple carriers, assigning different power levels to each carrier frequency at each base station, and/or offsetting sector antennas. The cell and/or sector coverage areas can be set so as to minimize or eliminate overlap between cell and/or sector boundary regions of different carrier frequencies. Mobile nodes traveling throughout the system can exploit multiple carrier diversity by detecting carriers and selecting to use a non-boundary carrier based on other system criteria in order to improve performance. Boundary carriers may, but need not be, identified and excluded from consideration for use by a wireless terminal.

Method of creating and utilizing diversity in a multiple carrier communication system

Methods of using superposition coding in a communications systems, e.g., a multi-user communications system. Superpostion coding in accordance with the invention occurs in the case of an uplink (1212, 1216) by transmissions of different wireless terminals (1204, 1206) transmitting using the same communications resource, e.g., simultaneously transmitting using the same frequencies. The signals combine in the communications channel resulting in one transmission being superimposed on the other transmission. The device, e.g., base station (1207), receiving the superimposed signals uses superposition decoding techniques to recover both signals. To obtain the benefit of the superposition, assignments of channel segments to multiple wireless terminals is controlled by the base station and/or transmission power levels are controlled by on or more wireless terminals sharing the same uplink communications resource, e.g., time slot, to make sure that the received signals from the different devices will have different received power levels making superposition decoding possible.

Controlled superposition coding in multi-user communication systems

A hearing aid includes a filter in an electrical feedback path, the characteristics of which filter are calculated to model acoustic coupling between the receiver and microphone of the aid. A limiter is inserted in the main electrical pathway between the microphone and the receiver to provide stability in the presence of sudden sound bursts. A noise signal is injected continuously into the electrical circuit and is used to adapt the characteristics of the filter to accommodate changes in the acoustic coupling. The level of the noise signal can be varied to match changes in residual signal level to maintain signal to noise ratio and to optimize rate of adaption commensurate with satisfactory hearing function while the noise itself is unobtrusive to the user.

Hearing aid having compensation for acoustic feedback

Systems, methodologies, and devices are described that can facilitate reducing power consumption associated with mobile devices. A mobile device can utilize a sleep mode controller that can facilitate selecting and/or switching to a desired sleep mode based in part on predefined sleep mode criteria. The sleep modes can include a non-sleep mode, light sleep mode, and/or deep sleep mode. The mobile device can employ an analyzer to evaluate information related to explicit signals, implicit signals, and/or the current sleep mode to determine whether a condition is met based in part on the predefined sleep mode criteria such that a transition to a different sleep mode is to be performed. If such a condition is met, the sleep mode controller can facilitate transitioning from the current sleep mode to a different sleep mode to facilitate reducing power consumption by the mobile device.

Using DTX and DRX in a wireless communication system

First and second sets of information are transmitted using a relatively large transmission block including a plurality of minimum transmission units (MTUs), each MTU corresponds to a unique combination of resources A first set of said MTUs is used in conveying said first set of information, said first set including at least a majority of said MTUs in the transmission block A second set of said MTUs is defined, eg, selected, for use in conveying said second set of information, said second set of MTUs including less MTUs than first set and at least some MTUs included in the first set The first and second sets of information are communicated by transmitting at least some MTUs included in said first and second sets of MTUs with the corresponding information modulated thereon The communicating of the information may be through superposition of the first and second information on shared MTUs

Methods and apparatus of enhanced coding in multi-user communications systems

The factors are b0, b1, b2....bi-1, where b is a base, e.g. 2, 3, 4.... and i the number of input signals; the products are then added and the sum is transmitted through a transmission channel; it is decoded at the receiving end by an amplitude filter and the transmission line is a multiplex line. Input signals are D.C. pulses. Addition is carried out by voltage superposition, and the whole dynamic range of the transmission channel (negative and positive amplitudes) is used for transmission. The input signals may be constant frequency A.C. pulses.

Transmission method using amplitude selection - involves multiplication of several signals in transmitter by different factors

The telephone exchange line coupling system comprises a three-dimensional, cubical lattice. Line terminations are taken to one face of the cube and each point of intersection can have a coupler unit - relay or electronic switch. Alternatively, input circuits may be connected to one face and output circuits connected to an opposite face of the cube. The numbers of inputs and outputs need not be equal. The three-dimensional frame system provides a large number of alternative interconnection arrangements and makes it possible to easily extend the system and to interconnect it with auxiliary units.

Telephone exchange line interconnection system - uses three-dimensional cubical lattic framework with couplers at nodal points

The receiver recognises and evaluates analogue signals having a specified frequency and is for use in communication and data processing systems. A device samples the received analogue signals and converts them into digital signals. A microprocessor is connected to this device and processes the digital signals by the quadrature correlation method controlled by a program. The specified frequency signals are detected. These detected signals are evaluated by a further device or by the microprocessor. Either single sinusoidal signals of specified frequency or multifrequency coded signals may be evaluated.

Receiver for recognition and evaluation of analogue signals - converts signals into digital form for processing by quadrature correlation

The acoustic feedback suppression system for loud-speaking telephone equipment is designed to prevent 'howl-round' between microphone and loudspeaker (L) (M). Part of the useful signal to the loudspeaker (s1) is added to the signal from the microphone (s2) in an adder circuit (A). Before entering the adder, the loudspeaker signal portion passes through a series connected chain comprising an inverter (I) adjustable attenuator (D) and an adjustable delay circuit (V). The output of the delay circuit is connected to a correction unit (E) which can be of the adaptive equalizer type of compensation circuit. The correction unit characteristic is matched exactly to the overall response of the loudspeaker, microphone and propagation path between the two.

Acoustic feedback suppression for loudspeaking telephones - adds portion of signal fed to loudspeaker to microphone circuit via phase shift network

The universal selector receiver comprises a central processor (22), ROM (23), clock generator (29), input gate (21), output gate (24) and analogue/digital converter (28). A shared data bus connects the gates, CPU and ROM. The system can be in the form of a microprocessor. The A/D converter is fed from a crosspoint matrix (KF) with multi-frequency code and dial pulse signals. The ROM contains a program with which to check which of these signals is present. Multi-frequency code signals are sampled at a frequency of 8 KHz which is employed in many telephone exchange installations. The processing of the signals is done using quadrature correlation methods. If dial pulse signals are detected, the processor switches the clock generator to a lower rate.

Rudolf Dr Ing Schehrer

Papers

Transmission method using amplitude selection - involves multiplication of several signals in transmitter by different factors

Telephone exchange line interconnection system - uses three-dimensional cubical lattic framework with couplers at nodal points

Receiver for recognition and evaluation of analogue signals - converts signals into digital form for processing by quadrature correlation

Acoustic feedback suppression for loudspeaking telephones - adds portion of signal fed to loudspeaker to microphone circuit via phase shift network

Universal selector receiver for telephone exchanges - has processor and control for multifrequency code and dial-pulse signals