Cirrus Logic Inc.

Pacific Communication Sciences, Inc.

Carl Thomas Hardin

James E Petranovich

Steven H Gardner

Sheldon L Gilbert

Kumar Balachandran

Andrew Wright

Steven Holmsen Gardner

A time sharing method and apparatus for frequency reuse in cellular communication systems. Frequency reuse is enhanced by synchronizing cell transmit/receive base stations in a cellular system to a common time base, and then sharing the available frequencies via allocated time slots. Cells using the same frequency that may interfere with each other are activated only during selected time intervals while same-frequency cells nearby are deactivated. The deactivated cells are then in turn activated while previously activated same-frequency cells nearby are deactivated. The frequency time slots may be of equal length, or longer time slots may be allocated to cells having higher usage rates, as determined in any of a number of ways. The time slots may be mutually exclusive, or may overlap. The time sharing technique of the present invention allows design of cell systems with many reuse patterns. Several particular cell reuse patterns are disclosed that provide good operational characteristics and low co-channel interference. The invention allows the use of a small number of cellular frequencies in a conventional cellular system without significant alteration of the existing system, and is particularly useful in two-way cellular paging systems. Improved reverse link data throughput is achieved via reuse of the reverse frequency channels.

Method and apparatus for frequency reuse in cellular communication systems

A method and apparatus for efficient use of both power and bandwidth in a cellular communications system in which a Mobile Unit preferably enters Sleep-Mode when no communications have occurred between the Mobile Unit and the Base Station over a predetermined amount of time measured by an 'Idle Timer'. Upon expiry of a Wake Timer, the Mobile Unit awakes from Sleep-Mode to determine whether a message is pending. Concurrently, the Base Station transmits a 'TEI-Notification' message directed to all Mobile Units to notify each Mobile Unit that has data pending. A system parameter determines the intervals at which the Base Station will transmit these notifications. Upon waking to receive a TEI-Notification message, the Mobile Unit determines whether the quality of the transmission is at least sufficient to allow the Mobile Unit to decipher the TEI-Notification message. If this minimal requirement is met, and the TEI-Notification message does not indicate that data is pending for the Mobile Unit, the Mobile Unit returns to sleep, even though the Mobile Unit may reside in a cell other than the cell associated with the Base Station currently assigned by the IS to communicate with the Mobile Unit. The Mobile Unit of the present invention does not monitor the forward channels on a regular basis, but rather waits until either the signal quality of the forward channel over which the Mobile Unit is receiving has degraded such that the TEI-Notification message can no longer be deciphered, or the TEI-Notification message indicates that a message is pending.

Method and apparatus for low power mobile unit for cellular

Reverse channel reuse scheme in a time shared cellular communication

A method and apparatus for improving the signal-to-interference ratio and signal-to-noise ratio of a signal transmitted on a reverse channel from a mobile transmitter in a land mobile communications system by using a sectored cell in which the same channel is received by each sector of the cell. Each directional antenna is coupled to a unique associated receiver tuned to the same frequency or frequencies as the other receivers associated with each other directional antenna within the same sectored cell. Depending upon the location of the mobile end system with respect to the antenna pattern of each directional antenna, each signal will typically be redundantly received over more than one, but less than all, of the antennas. In accordance with the present invention, only one of the received signals is to be communicated from the base station to an intermediate system and all others are to be discarded. If multiple copies of the same message are received, then the control computer couples only one such copy to the intermediate system and discards each of the others.

Method and apparatus for improving receiver performance in a land mobile

Competition between subscriber stations attempting to access reverse channels in response to Temporary Equipment Identifier (TEI) messages is limited by requiring the subscriber stations to wait for a predetermined amount of time. The time delay is selected on the basis of a random number and a factor based upon the number of TEI messages broadcast. The method for determining response opportunities for subscriber stations also includes a back-off phase at the first stage. The time delays to the defer phase is based upon a random period of time and a predetermined maximum based upon the time needed for the microslots containing a TEI message.

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Encinitas, CA, United States of America

Carl Thomas Hardin