13-06-2012, 03:47 PM
A QoS Based Scheduling Algorithm in OFDMA Broadband Wireless Systems
A QoS Based Scheduling Algorithm in OFDMA .pptx (Size: 1.1 MB / Downloads: 33)
Problem of Radio Resources
Scarcity
Diverse Quality of Service (QoS) requirements
Wireless channel conditions complicate scheduling and radio resource management
Effective use of Channel Access schemes FDMA, TDMA, CDMA, OFDMA to get high system performance
Scheduling
Scheduling scheme is defined as the method of user selection and how to allocate available resources to selected user.
Scheduling scheme intelligently allocates radio resources to achieve high system performance in terms of Throughput and fairness.
Need to have scheduling algorithms which incorporate QoS requirements
OFDMA based BWS
Bandwidth is divided into multiple subcarriers
All subcarriers orthogonal to each other
A symbol comprises all data subcarriers
Multiple symbols combined with time forms a frame of OFDMA
Each of the time frequency units forms the smallest two dimensional resource