Concept and model of a metamaterial based passive wireless temperature sensor...
Afda asynchronous flipped diversity aloha for emerging wireless networks with long and heterogeneous delay
1. AFDA: AsynchronousFlipped DiversityALOHA for Emerging Wireless
Networks With Long and Heterogeneous Delay
Abstract:
The design of random media access control (MAC) protocol renews great
attention for emerging challenged wireless environments, where the
propagation delay is long, heterogeneous, and/or varying, such as satellite
or underwater acoustic sensor networks. In these environments, the
existing MAC solutions based on slotted transmissions, carrier sensing, or
channel reservation by control packets are no longer favorable or even
feasible. In this paper, we propose the asynchronous flipped diversity
ALOHA (AFDA)to tackle the challenges based on a new diversity
transmission scheme. Different from the existing diversity transmission
schemes, each data packet and its flipped replica are transmitted back to
back, and the zigzag decoding technique is adopted to resolve collisions.
The performance of AFDA has been evaluated by analysis and simulations.
The results show that, without time synchronization or handshaking
requirements, the performance of AFDA is unaffected by the duration or
variation of the propagation delay, and it substantially improves system
2. performance in terms of throughput, packet loss ratio,
and network admission region.
