Browsing by Author "Ching Yao"

Now showing 1 - 5 of 5

Capacity-based compressed mode control method for inter-system handover in universal mobile telecommunication system
(2010-09-14)
Huang
;
Ching Yao
;
Chang
;
Cheng Ta
;
Ho
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.
Multi-slope handoff algorithm for controlling dynamic communication quality in wireless communications
(2007-07-10)
Huang
;
Ching Yao
;
Tsai
;
Ming Yuan
;
Huang
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.
Scheduling method for supporting quality of service (QoS) in wireless local area network (WLAN)
(2009-04-07)
Huang
;
Ching Yao
;
Fan
;
Yu Long
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 Tm is below the threshold Tthr; 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 Tm is larger than the threshold Tthr.
Two-tier call admission control method in IEEE 802.11 WLAN
(2010-09-07)
Huang
;
Ching Yao
;
Shih
;
Yuan Hwai
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.
Vertical handover control algorithm for WLAN and UMTS
(2008-04-22)
Huang
;
Ching Yao
;
Chou
;
Chie Ming
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.