Lucent Technologies Inc.

National Yang Ming Chiao Tung University

Joe Huang

Bulin B Zhang

Colin L Kahn

Sudheer A Grandhi

Krishnan Kumaran

Simon C Borst

Ching Yao Huang

Terry Si-Fong Cheng

Bee Yun Yu

Sanjiv Nanda

Stanley Vitebsky

Walid Ahmed

Mathew Thomas

Sarath Kumar

Asif Dawoodi Gandhi

Xiao Cheng Wu

Philip Lamoureux

Myles Patrick Murphy

Richard Thomas Aiken

Lei Song

Marc Benedict Ibanez

Terry Cheng

I-Fong Antonio Wu

Kevin John Murphy

Aparajita Misra

Ming Yuan Tsai

Devesh T Patel

Melanie M Wang

Colin Leon Kahn

A multi-slope handoff algorithm for controlling dynamic communication quality in wireless communications is proposed to let a mobile node adjust the handoff slope according to different communication connection situations for setting the optimum add/drop connection trigger thresholds. The algorithm comprises the following steps. First, a mobile node receives pilot strengths of its service pilot and nearby pilots to produce an aggregate strength. Next, the mobile node determines whether to perform handoff according to the magnitude of the aggregate strength. The handoff action is then controlled by multi-slope handoff operations to set an appropriate slope and to calculate the add/drop connection trigger thresholds when performing handoff. Finally, the pilot to be connected is selected based on the communication quality at that time. In this way, the quality of the communication service can be enhanced, the connection power consumption can be lowered, and the communication channel usage can be reduced.

Multi-slope handoff algorithm for controlling dynamic communication quality in wireless communications

A method and apparatus for directing energy in a plurality of azimuth directions. The amount of energy directed in the azimuth direction of a mobile terminal is a function of the location and acceptable receive strength of at least two mobile terminals. The function is such that the strength of an EM field at the location of any of these two mobile terminals is at least as large as, but not significantly larger than, needed for that mobile terminal to acceptably receive the signal carried by the EM field. The amount of energy to be directed in the azimuth direction of a mobile terminal is arrived at by first determining for each one of the mobile terminals an EM field that would have to be generated for the mobile terminal in order to provide an acceptable receive strength thereat, the determining taking into account the strength, at the location of the mobile terminal, of EM fields previously determined for others of the mobile terminals. This determining is repeated until the EM fields determined for at least two of the mobile terminals provide an EM field strength for each of these two mobile terminals that is substantially equal to its adequate receive strength. This determining is repeated until the EM fields converge. The amount of energy is then determined based on the EM fields thus determined. After the EM fields converge, the composite EM field that has thus been arrived at is the aforementioned composite EM field whose strength at the location of any of the at least two mobile terminals is at least as large as, but not significantly larger than, needed for that mobile terminal to acceptably receive the signal. This saves system resources, reduces interference with other signals, and increases the number of signals that can be transmitted simultaneously, which results in an increase in capacity, and therefore in profitability of the wireless communication system.

Shaping of EM field for transmission to multiple terminals

In the method of processing soft handoff information at a base station, soft handoff information of a mobile station is received at the base station. The soft handoff information indicates at least a number of base stations in an active list of the mobile station. The active list is a list of base stations involved in a call of the mobile station. The base station applies a rules set to the soft handoff information to determine changes in the active list. The rules set requires more stringent conditions be met to add a base station to the active list when the active list includes a first number of base stations as compared to when the active list includes a second number of base stations; wherein the first number is greater than the second number. The determination results are then sent to the mobile station.

Method of processing soft handoff information at a base station

A method for controlling access of a subscriber station to a wireless communications system facilitates the maintenance of a performance target of the reverse link and desired geographic coverage of the reverse link. The method for controlling access of a subscriber station to a wireless communications system includes measuring a first performance indicator and a second performance indicator for a reverse link associated with a subscriber station seeking access to a wireless communications system. A blocking threshold value is established based upon the measured second performance indicator and may be adjusted to allow more or less blocking based on any additional metrics that characterize the performance of the current subscriber stations. The decision to grant or deny access of the subscriber station to the wireless communications system is determined based on a comparison of the measured first performance indicator to the established blocking threshold value.

Method and system for controlling access of a subscriber station to a wireless system

Soft handoffs in an IS-95 CDMA system or other wireless communication system are controlled using an enhanced set of soft handoff parameters which allow the system to adapt more readily to changing radio frequency (RF) conditions. In an illustrative embodiment, values for particular ones of the soft handoff parameters are selected in accordance with a set of rules, including rules such as, e.g., select the minimum value of add threshold among the members of an active set of pilots for a given mobile station; select the maximum value of drop threshold among the members of the active set; select the minimum value of drop threshold timer among the members of the active set; and select the minimum value of comparison threshold among the members of the active set. A quality measure is then determined for each of the members of the active set, based on one or more of the selected soft handoff parameter values and values of one or more additional parameters, e.g., add intercept, drop intercept and slope parameters, associated with those members. Particular values of the additional parameters are then selected based on the quality measures. The selected parameter values are then utilized in a soft handoff process, e.g., in a soft handoff process in which the given mobile station is directed to handoff from a primary base station to another base station of the system.

Methods and apparatus for enhanced soft handoff in a CDMA wireless communication system

A method for controlling downlink power in a time-division multiplex wireless system may provide different downlink transmit signal powers to different time-division multiplex channels of a single carrier. A base station receives a measured signal parameter data for a downlink transmit signal of a time-division multiplex channel. The base station determines an initial adjustment for the downlink transmit signal power of the time division multiplex channel if the measured signal parameter data differs from a target signal parameter data. The base station determines a revised adjustment for the downlink transmit power of the time division multiplex channel based on the initial adjustment and at least one adjustment range as appropriate to achieve synchronization of the demodulation of the downlink transmit signal.

Method and system for dynamic downlink power control in a time-division, multiplex wireless system

Sharing the existing sector antennas at the base station each of which corresponds to one sector of the outer communication coverage area to create an omnidirectional inner communication coverage area. When transmitting or receiving data from a mobile in one sector of the outer communication coverage area only one antenna is used, and when transmitting or receiving data from a mobile in the inner communication coverage area all the antennas are used. This allows an increase in capacity of the hybrid inner/outer sectored cell without the additional cost of adding further antennas.

Antenna configuration for a hybrid inner/outer sectored cell

Call processing overload at a base station of a cellular wireless network is controlled by monitoring a level of call processing at the base station, and reducing a present handoff rate for active users when the call processing level exceeds a first threshold less than a maximum call processing capacity. When the call processing level at the base station exceeds a second threshold greater than the first threshold, a present rate of call originations or terminations is reduced while further reducing the handoff rate.

Processing overload control at base stations of cellular wireless communication systems

In a cellular system, channels are assigned for new calls using a flexible channel allocation algorithm that is a hybrid of a measurement-based dynamic channel assignment (MBDCA) algorithm and a reuse-distance criterion algorithm, such as a cost-function-based DCA (CFBDCA). In one embodiment, the MBDCA algorithm is implemented at each cell site in the cellular system and generates a list of candidate channels for each new call. The list is transmitted to the mobile switching center (MSC), which implements the CFBDCA algorithm to select a particular channel from the list of candidate channels for the new call.

Flexible channel allocation for a cellular system based on a hybrid

Operations in a cellular system are controlled based on cost values that are generated using neighbor association. In neighbor association, each cost value corresponds to a cost of assigning a candidate channel to a first cell in the cellular system, assuming that the candidate channel is already assigned to a second cell in the cellular system and each cost value is based on an average power attenuation for all of the cells in the cellular system that share the same tier as the second cell with respect to the first cell, wherein the average power attenuation is based on the reuse distances between the first cell and the cells in the same tier. In one embodiment, the cost values are used in a cost-function-based dynamic channel assignment (DCA) algorithm that is, but does not have to be, applied to a list of candidate channels generated using a measurement-based DCA algorithm.

Controlling operations in a cellular system using neighbor

In a cellular system, a new cell measures signal strengths of different channels being used by existing cells. The new cell generates a list of candidate channels corresponding to the channels with the greatest signal strength and transmits the list to the mobile switching center (MSC) of the cellular system. The MSC determines which of the candidate channels correspond to beacons in existing cells and transmits configuration information to the new cell for those corresponding existing cells. In this way, the new cell automatically receives configuration information on its neighbor cells. If the MSC determines that the number of candidate channels that are beacons is too small, the MSC will ask the new cell to transmit additional candidate channels (i.e., those having even lower signal strength).

Automatic neighbor identification in a cellular system

In a cellular system, channels are assigned for new calls using a cost-function-based dynamic channel assignment (CFBDCA) algorithm. In one embodiment, the CFBDCA algorithm is implemented in the cellular system's mobile switching center (MSC), which maintains a database containing one or more cost tables and a busy channel table. The entries in the cost tables reflect the costs of using a candidate channel in one particular cell of the cellular system, assuming that the channel is already being used in another particular cell. The entries in the busy channel table identify which channels are currently being used in which cells. The CFBDCA algorithm uses the cost tables and the busy channel table to generate cost of reusing the channel (CORC) values. Depending on the implementation, the CFBDCA algorithm of the present invention may or may not be used in conjunction with a measurement-based DCA (MBDCA) algorithm. If so, then the CFBDCA algorithm may be applied to a list of candidate channels generated using the MBDCA algorithm.

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Parsippany, NJ, United States of America

Joe Huang