Hughes Aircraft Company

Hughes Electronics Corporation

Charles A Barnett

Ashok D Mehta

Lou King

Stanley Edward Kay

Youngky Kim

Naresh Durvasula

A base transceiver station has a signal strength receiver and is capable of transmitting a directed retry signal. A processor connects to the signal strength receiver and compares a received signal strength to a predefined threshold. The processor causes the base transceiver station to send the directed retry signal if the received signal strength is less than the predefined threshold. A method is provided where a characteristic of a signal received at a base transceiver station is measured and compared to a predefined threshold. A directed retry is sent if the signal characteristic is less than the predefined threshold, and a communication channel is established if a response to the directed retry is received at the base transceiver station.

Method and apparatus for resolving multiple call accesses in a wireless communication system

The present invention relates to an apparatus and method for performing a handoff in wireless communication system. The method includes the steps of establishing communication between a mobile subscriber and a serving cell, determining whether a target cell and the serving cell are collocated, sending a normal burst handoff command to a mobile subscriber, sending a normal burst from the mobile subscriber to the target cell including a time offset, and establishing communication between the mobile subscriber and the target cell. The apparatus relates to a wireless system including a serving cell and a target cell in communication with a mobile subscriber. The mobile subscriber is sent a normal burst handoff, including an instruction to the mobile subscriber to transmit in normal bursts and to main current alignment, when the target cell overlaps the serving cell.

Method and apparatus for performing a handoff in a wireless

A mechanism for handing off between an overlay cell (48) and an underlay cell (50). The underlay cell (50) is smaller than and has a common area with the overlay cell. A threshold level (RSSI-THP) is established which corresponds to the sum of a nominal threshold level (RSSI-U) and a value obtained by subtracting the current attenuation level (MT) from the minimum attenuation level permitted by the underlay cell (MU). If the RF signal level of the serving cell (RSSI-SRV) is greater than the established threshold level (RSSI-THP), the mobile unit is handed off to the underlay cell (50), if not already in that cell; and handed off to the overlay cell (48) if equal to or less than the established threshold level (RSSI-THP), if not already in that cell.

Handoff between overlay and underlay cells

Each cell has an assigned classification that determines its inclusion in a measurement list for handing off. The candidate cells, which are selected from the measurement list are given priority level assignments. The priority levels are implemented by the candidate neighboring cells measured RF signal strength; and the order of handing off is arranged in accordance with the adjusted RF signal strength.

Prioritization of neighboring cells

A method and system for handing off an on-going communication from a serving cell to a neighboring cell of a cellular communication system having mobile units with a scanning capability. A dynamic threshold is calculated for effecting the handoff under certain operating criteria. The minimum attenuation level of the mobile unit and the minimum level permitted by a neighboring cell is used in selecting the dynamic threshold.

Dynamic thresholding for mobile assisted handoff in a digital cellular

A method and system for selecting the best handoff candidate cell at times when the number of neighboring cells that meet the measurement criteria is greater than twelve a measurement list is generated. The cells are assigned a handoff measurement priority wherein a handoff priority of zero is assigned to 12-N cells where N is between 1 and 6. A priority of 8 is assigned to the worst N cells. A new measurement list is generated using the 12-N cells and other unreported cells having a higher priority than the N worst cells.

Method and apparatus for mobile assisted handoff

A method and system for handing off an on-going communication from a serving cell to a neighboring cell of a cellular communication system having scanning receivers associated with each base transceiver station. A dynamic threshold is calculated for effecting the handoff in accordance with various operating conditions. The current mobile minimum attentuation level, (MT) the minimum permissible attenuation level of a serving (MS) cell and a neighboring cell (MN), together with the RF signal strength of the mobile unit at the neighboring cell (RSSI-NBR) and the serving cell (RSSI-SRV) are used in calculating a dynamic threshold (RSSI-THP).

Method and system for effecting handoff in a cellular communication

Cellular handoff is improved by tailing or adapting the measurement time based on the characteristics of the received signal intensity or power. More particularly, base stations typically measure mobile signal power in order to determine the necessity for handoff and the identity of a new cell. The measurement time must be of a duration which is sufficient to characterize the environment of the mobile. In accordance with the invention, the duration of the measurement time is determined from the received signal itself. Once the duration of the measurement time is determined, that data may be passed to a target cell along with other handoff data.

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Sterling, VA, United States of America

Charles A Barnett