A MAC Layer Allocation Method for IEEE 802.15.4 Based on GTS Mechanism

• Main Authors: Wei-Shen Chen, 陳威勝
• Other Authors: 黃德成
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/24230436288971928186

碩士 === 國立中興大學 === 資訊科學與工程學系所 === 100 === As technology advances, mobile communication commodities change and improvement progress with each passing day. Wireless networks play an indispensable role in our life. In [15] has been the release of IEEE 802.15.4 standard that defines the medium access control (MAC) layer and the physical (PHY) layer for low-rate, wireless personal area network (LR-WPAN). [15] also defines contention avoidance period (CAP) and the contention free period (CFP) to improve wireless network performance. Upper layers are defined by ZigBee Alliance. Before transmission data, every guarantee time slot (GTS) must be allocated for each device during CFP through the CAP. However, it is hard to get the access right of using GTS when there have more devices to share the bandwidth within the same period. It also leads to decrease utilization and reduce cycle network performance. [1] proposed the method of adopting the pre-allocated GTS by ZigBee network address parameters Cm and Rm to cope with the contention issues. However, the utilization of CFP is low by the method mentioned in [1]. In this paper, a ratio GTS allocated scheme is presented to improve the problem of more devices to share the bandwidth within the same period. In addition, we proposed the method for GTS allocation not only conduct the pre-allocation mechanism without CAP, but also raise the utilization of CFP and reduce transmission time.