Lucent Technologies Inc.

National Yang Ming Chiao Tung University

Alcatel-lucent USA Inc.

Mediatek Incorporation

Ching Yao Huang

Terry Si-Fong Cheng

Qi Bi

Stanley Vitebsky

Frances Lin Jiang

Joe Huang

Yuen-Yin L Koo

John Kenney Burgess

Pi-Chun Chen

Patrick Li

Dan Anthony Balogh

Bee Yun Yu

Wen-Yi Kuo

Carl Francis Weaver

Xiao Cheng Wu

Shen-De Lin

Qi Bl

Shawn S Yu

Meng-Shiang Lin

Amit Shah

Ming Yuan Tsai

Cheng Ta Chang

I-Fong Antonio Wu

Alexandro Federico Salvarini

Chie Ming Chou

Yu Long Fan

Yuan Hwai Shih

Chieh Yuan Ho

A handoff method. A mobile station calculates and records the strength of a pilot signal from a cell as reference strength if a handoff occurs in a first system. The mobile station further adjusts the reference strength according to the effect caused by forward and reverse links between a base station and the mobile station, and performs a handoff between the first and a second system if the strength of the pilot signal reaches the reference strength.

Handoff methods, and devices utilizing same

The Inter-System handover is one of the key features in the third generation cellular systems. The compressed mode, with variable transmission gaps and power levels, is standardized to support the inter-frequency system handover. To minimize the use of system resources while maintaining the border-cell handover quality, a capacity-based compressed mode control method of the present invention is proposed. Considering the tradeoff between the capacity and the communication quality, the control method can adaptively manage the compressed mode operation based on the potential impacts on the capacity and the effectiveness of the compressed mode measurement. The present invention will improve the effectiveness and performance of the compressed mode operation.

Capacity-based compressed mode control method for inter-system handover in universal mobile telecommunication system

The present invention discloses a two-tier call admission control algorithm in IEEE 802.11 WLAN. The two-tier call admission control algorithm is given to improve the overall system throughput and guarantee the quality of service of every single user in the WLAN.

Two-tier call admission control method in IEEE 802.11 WLAN

In the method, scheduling of a plurality of users for receiving transmitted data is prioritized within a communications system. A next data transmission among the plurality of users is allocated based on the prioritized scheduling.

Method and apparatus for scheduling users to allocate data transmissions in communications systems

In the method, an average user throughout over all active users is computed, and each user's user perceived throughput is compared against the computed average throughout. Based on the comparison, the scheduling of the plurality of users is prioritized. In an embodiment, a priority adjustment factor is applied to each user to prioritize the scheduling of users to receive a data transmission. The priority adjustment factor is determined based in part on an update function. The update function is proportional to a calculated difference between each user's user perceived throughput and the average user throughput. Based on the sign of the update function, the priority adjustment factor is either incremented or decremented, and hence, prioritization of users is ordered. The output of the scheduler is user identifying information that informs the base station to transmit data in a current time slot to the identified user determined as the highest priority user by the scheduling method.

Scheduler method and apparatus for communication systems

A method for polling of stations in a Wireless Local Area Network (WLAN), including the steps of: obtaining Quality of Service (QoS) information related to the stations; assigning two timers to each WLAN service requiring QoS guarantee, one for uplink transmission and the other for downlink transmission; starting a Controlled Access Period (CAP) when a minimum timer Tis below the threshold T; polling the station with the minimum timer; updating the minimum timer after a polling message is sent; quitting CAP and permitting the resource contention if the minimum timer Tis larger than the threshold T.

Scheduling method for supporting quality of service (QoS) in wireless local area network (WLAN)

In this invention, a novel vertical handover control algorithm, consisting of a throughput-based mapping function, QoS-based dynamic handover thresholds, and performance-based trigger timers, are proposed to resolve uncommon pilot problem, QoS requirements, and ping-pong effects, respectively. An analytic model based on a finite state machine is developed to evaluate the proposed algorithm in terms of the handover frequency and achievable throughput. A numerical analysis is also provided to further quantify the performance impacts.

Vertical handover control algorithm for WLAN and UMTS

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 code-division multiple access power control for paging channel power and initial traffic channel power dynamically determines optimum initial channel power in accordance with pilot signal strength of a pilot signal as received at a mobile station and current forward link loading of the desired sector. The optimum initial paging channel power and initial traffic channel power may be determined either at a base station or a mobile switching center of the mobile communication system. A paging signal or call is transmitted from the base station to the mobile station over a paging channel and a traffic channel at the optimum paging channel and initial traffic channel power.

CDMA power control for paging and initial traffic channel power

A communication system includes a base station and a plurality of remote stations wirelessly communicating with the base station. The base station determines a respective RF quality for each remote station. In response to a request for RF resources from a given remote station, the base station determines whether admission of the given remote station would exceed an RF power budget threshold. If the RF power budget threshold would not be exceeded, the RF quality is compared to a first quality threshold to determine whether to allocate the requested RF resource to the given remote station. Otherwise, the RF quality is compared to a second quality threshold more stringent than the first quality threshold to determine whether to allocate the RF resource to the given remote station. The base station may further determine whether to allocate requested RF resources on the basis of a priority of the requested resources.

Communication system and method for quality-based call admission control and scheduling

A method and apparatus for transmitting a burst of data over a supplemental channel on just one leg of a handoff by changing the maximum allowed burst duration of the data to be transmitted over the supplemental channel as a function of the future and/or current characteristics of the communication link of the leg(s) of the handoff. The data is then transmitted over just one leg of handoff using the maximum allowed burst duration. By changing the parameters of the data, the data may still be acceptably received at the mobile terminal over just one leg of the soft handoff even when the strength of the pilot signal used for the supplemental channel changes significantly. In an illustrative embodiment of the invention the stability of the communication link is used as a way of ascertaining the future conditions of the communications link.

Data transmission in a wireless communication system

In the method according to the present invention, a signal from a mobile station is received. The standard deviation of the symbol error rate is determined, and power control with adaptive adjustment of an amount of change in the target signal-to-noise ratio is performed based on the determined standard deviation of the signal error rate and a target associated therewith.

Method for enhanced power control by adaptively adjusting an amount of change in a target signal-to-noise ratio

A procedure for triggering a handdown or a handoff a mobile station served by a base station of a cellular wireless communication system. A tolerable path loss for signal links between the base station and a mobile station located within the base station's cell, is initially determined. A control signal is radiated at a known transmit power level from the base station over its cell. A receive power level threshold is determined for the control signal for reception by the mobile station, according to the transmit power level and the tolerable path loss. A handoff of the mobile station is triggered after deriving the received power level of the control signal at the mobile station, and determining that the received power level is less than the receive power level threshold. In one embodiment, a mobile station reports to a serving base station only after the former determines that the received power level of a control signal from the base station is less than a threshold level initially provided to the mobile station by the base station. The procedure is applicable, e.g., to base station cells of a first CDMA cellular system which cells border on cells of an analog (AMPS) or a second CDMA cellular system.

Triggering handdowns and handoffs of mobile stations between bordering cells of cellular wireless communication systems

A method for allocating traffic between multiple carriers in a wireless communications system measures loading on the communication system and selects an appropriate carrier from multiple carriers, based upon the loading measured. A first carrier is selected if the load on the first carrier is lower than or equal to the lowest loading of any supplemental carrier among the multiple carriers. If the load on the first carrier is not lower, then the subscriber may be assigned either to a supplemental carrier or the first carrier. The carrier assignment of the subscriber depends upon a predetermined threshold, which preferably considers actual or estimated differential interference between the first carrier and the supplemental carrier.

Enhanced channel allocation among multiple carriers in a spread spectrum communications 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.

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Randolph, NJ, United States of America

Ching Yao Huang