Juniper Networks, Inc.

Alcatel

Sequans Communications Limited

Emmanuel Lemois

Joseph Boutros

Fabien Buda

Philippe R Sehier

Bertrand Debray

Michel Cohen

Thierry Quignon

Cyril Bertrand

Amelie Duschesne

Laurent Cuvelier

Jo&euml;l Richard

Amélie Duschesne

A system for determining the burst start timing of a signal includes logic configured to receive the signal, generate correlation moduli and generate a first timing output based on the correlation moduli. The logic may also be configured to receive operating mode information and timing information and generate search controls. The logic may further be configured to identify a maximum of the correlation moduli using the search controls and determine a second timing output associated with the maximum correlation modulus. The second timing output represents a more accurate approximation of a burst start time than the first timing output.

Coarse time synchronization

The present invention concerns a method for controlling the interference level generated by a mobile station comprising at least steps: selecting at least one neighbor base station; estimating a first attenuation value between the mobile station and a current base station, and at least a second attenuation value between the mobile station (MS) and the neighbor base station; estimating an interference level: I_level=BS_RSS+L&#x2212;L wherein BS_RSS is a first received signal strength at the base station, from the mobile station, Lis the first attenuation value, and L is one second attenuation value estimated in preceding step, comparing the interference level to a reference interference level, and according to the result of the comparison, sending to the mobile station at least information relative to a maximum transmitted signal strength.

Method for controlling interference generated by a mobile station on neighbor base stations

Coarse timing synchronization

A method of synchronizing a base station of a wireless communication system and a subscriber communication equipment located in the coverage area of the base station by compensating a sampling frequency offset in the subscriber equipment by interpolating input and/or output signals of a radio frequency part of the communication equipment to generate samples corresponding to the original symbol timing of the base station, and compensating the carrier frequency offset from the estimate of the sampling clock error.

Method and system for synchronizing a base station of a wireless communication system and a subscriber communication equipment

Burst detection with high accuracy is achieved with a single autocorrelation circuit. Autocorrelation is performed using a preamble-embedded correlation sequence chosen such that a steeply sloped peak characterizes the autocorrelation response. The autocorrelation circuit is preferably used multiple times per clock period to deliver correlation moduli at sub-clock multiples. A contrast function makes a weighted comparison of each correlation modulus output by the autocorrelation circuit relative to adjacent correlation moduli. The contrast output defines a burst start-time uncertainty-window in a manner that is independent of signal level variability attributable to different operating conditions. A search is performed within the uncertainty window to identify the correlation maximum. Depending on the system mode (e.g., traffic mode vs. ranging mode), a priori knowledge may be preferred to the contrast output for defining the timing uncertainty window of the search. The time associated with the correlation maximum is the approximate time of the start of the burst. Burst-start indications so identified are accurate within the sub-clock multiple associated with the autocorrelation results. Parabolic interpolation is subsequently preferably used to deliver an overall burst-start indication with additional accuracy.

Methods and apparatus for efficient and accurate coarse timing synchronization in burst demodulators

Method and system for enhancing channel capacity in a Point-to Multipoint radio communications system that includes terminal stations () of different kinds, such as residential terminals and business terminals, with different link budget requirements i.e. different signal-to-noise ratio. The method is characterized by the selective use of different channel coding codes such as forward error correction (FEC) codes, in the different concurrent channels, depending on a pre-defined category of an addressed subscriber. The multiplexing method used may be CDMA (Code Division Multiple Access) and TDMA (Time Division Multiple Access). Each terminal station () is in turn equipped only with an appropriate decoder, depending on its kind, e.g. residential or business.

Method and system for enhancing channel capacity in a point to multipoint radio communications system having different kinds of terminals

In a radiocommunications system having physical channels each including at least one logical channel, the invention proposes transmitting both the means for acquiring and tracking synchronization and the system information addressed to user stations in a single logical channel referred to as the &ldquo;synchronization&rdquo; channel. For this purpose, the synchronization channel carries a repeated detection word ( ) together with system information ( ) between repeats of the detection word. The system information is subjected to spreading prior to being transmitted over the synchronization channel. The invention makes it possible to limit the amount of system resources that are devoted to providing the functions of synchronization and of broadcasting system information.

Module channel for acquiring and tracking in a radio communication system

The invention provides a spread-spectrum transmission system with multiple carrier modulation in which the signals for transmission over each of the subcarriers are filtered prior to being transmitted over the subcarrier, thereby making it possible on reception to synchronize the various subcarriers in time, and in which each subcarrier carries a plurality of chips that result from spreading a single symbol. With coherent modulation, the number of chips resulting from spreading a single symbol and transmitted over each subcarrier is selected so as to enable the various subcarriers to be put into phase alignment by recombining the chips coming from the same symbol on each subcarrier. With differential modulation, the transmission over each subcarrier of chips resulting from spreading a single symbol provides resistance to jamming by limiting recombination losses because of the differential modulation.

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Paris, France

Emmanuel Lemois