An efficient uplink mapping scheme for VoIP services in the IEEE 802.16e OFDMA system

2008 ◽  
Vol 62 (10) ◽  
pp. 768-776 ◽  
Author(s):  
Jae-Woo So
Keyword(s):  
Ieee 802.16E ◽  
Ofdma System ◽  
Mapping Scheme ◽  
Voip Services

New Uplink Initial Ranging Scheme for IEEE 802.16e OFDMA Systems

2011 ◽  
Vol 52-54 ◽  
pp. 1783-1787 ◽  
Author(s):  
Chien Sheng Chen ◽  
Wen Hsiung Liu ◽  
He Nian Shou ◽  
Yu Jen Ho
Keyword(s):  
Computational Complexity ◽  
Ieee 802.16E ◽  
Initial State ◽  
Bandwidth Request ◽  
Ofdma System ◽  
System A ◽  
Initial Ranging ◽  
Code Identification ◽  
And Performance ◽  
Performance Results

Ranging is one of the most important processes in the uplink of the IEEE 802.16e OFDMA system. A ranging process includes the initial ranging, periodic ranging, handover ranging, and the contention bandwidth request. Initial ranging provides network entry, uplink synchronization, and system coordination. In the initial state of the transmission process, multiple users randomly transmit selected ranging code sets and BS identifies a specific user using the ranging code identification and uplink synchronization using the transmission delay estimation. In this paper, we discuss the details of the initial ranging and propose an algorithm to carry out a successful ranging process. The performance results and the comparison of computational complexity with the traditional method are also presented. It is noted the proposed algorithm can offer a better trade-off between computational complexity and performance.

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