Nortel Networks Corporation

Northern Telecom Limited

Brian James Lehman

Bradley John Morris

Roland A Smith

Charles Tremlett Nicholls

Gregory Carleton

Blaine Quentin Geddes

Gilles Monette

Systems and methods are disclosed to maintain synchronous communications that uses a global positioning system satellite, a primary communication unit, and a secondary communication unit. The satellite based time reference broadcasts a reference signal to the primary communication unit and the secondary communication unit. The primary communication unit contains a high quality oscillator, and operates a virtual model of a secondary oscillator which is located in the secondary communication unit. The primary and secondary units have synchronous communications with each other by using a global positioning system satellite broadcast as a reference signal. If the secondary unit loses its signal from the global positioning system, the secondary oscillator enters a holdover state and transmits a notification of the holdover state to the primary communications unit. The primary communication unit then transmits time insensitive synchronization data based upon the virtual model through the packet switched network to the secondary communications unit to maintain synchronization.

Enhanced holdover for synchronous networks employing packet switched network backhaul

A basestation transceiver simultaneously addressing multiple air interface standards with cost-effective and efficient allocation of the resources available at the transceiver. The invention significantly reduces the redundancy of the radio frequency equipment used in the transceiver by the use of a common digitizing rate selected to simultaneously accomodate all of the air interface protocols serviced.

Common digitizing rate for multiple air interfaces for generic cell sites in cellular radio

A selection diversity system and method for use in a TDMA (time division multiple access) radio system, particularly suited for DECT (Digital Enhanced Cordless Telephone) applications, in which a single receiver makes a performance measurement on each of two antennas in sequence during the beginning of a received data burst, the beginning of the burst being determined by a timing signal fed back from a previous burst. A slicing level used in the receiver to perform threshold detection is continuously improved during the measurements of the two antennas, but held while switching between the antennas. The previously unused antenna is measured first to minimize the likelihood of having to perform two antenna switches.

Preamble based selection diversity in a time division multiple access

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Ottawa, Canada

Brian James Lehman