Portal de Periódicos da CAPES

A Real-Time, Distributed, Directional TDMA MAC Protocol for QoS-Aware Communication in Multi-Hop Wireless Networks

2021; Institute of Electrical and Electronics Engineers; Volume: 9; Linguagem: Inglês

10.1109/access.2021.3057587

2169-3536

Shivam Garg, Venu Sri Sushma Kuchipudi, Elizabeth Serena Bentley, Sunil Kumar,

Energy Efficient Wireless Sensor Networks

Time division multiple access (TDMA) based medium access control (MAC) schemes are widely used for communication among directional nodes since they can provide a conflict-free transmission schedule.However, the existing directional TDMA schemes introduce significant overhead and delay, and cannot adapt in real-time to topology changes in a directional multi-hop network.These schemes also incur considerable overhead and delay in order to support the QoS (quality of service) traffic.In this paper, a novel, real-time, distributed, directional TDMA scheme is presented for directional multi-hop wireless networks.This scheme adapts to the topology changes and/or flow requirements in real-time, and facilitates QoSaware communication with no notification overhead.In the proposed scheme, the 1-hop neighborhood of every node is divided into fully connected 1-hop neighborhoods, which allows the node to intelligently serve multiple routes without requiring a globally converged scheduling solution.This feature allows the use of a low-complexity rank-based mechanism to obtain a distributed, real-time transmission schedule for a directional multi-hop network.The following new features are also added in the proposed scheme: (i) REQ period which reduces slot wastage, (ii) throughput scaling which ensures fairness and helps in congestion management, and (iii) piggyback reservation period which increases the spatial reuse and adapts to the dynamic requirements of multiple flows in real-time.The control-period overhead in our scheme is low and linearly changes with the number of nodes in a fully connected 1-hop neighborhood, instead of the total number of nodes in the entire network.Simulation results and comparisons with other recent, distributed TDMA-based schemes show that our scheme provides a higher throughput with very low control overhead for both static and mobile network topologies. INDEX TERMSDirectional communication, distributed medium access control (MAC), multi-hop network, mobile network, quality of service (QoS), time-division multiple access (TDMA).remains unaware of when its transmitter (or neighbor) node will start the communication, it fails to beam-form in the direction of transmission and therefore misses the packet(s) which aggravates the deafness problem [1]-[3], [5]-[11].To address this issue, some CSMA-based schemes [9], [11], [12] use two antenna system, where omnidirectional antenna overhears transmissions of neighbor nodes and SBA is used for data packet transmission.However, the use of an omnidirectional antenna reduces the benefits of spatial reuse and leads to the well-known gain-asymmetry problem [1], [13], [14].In some other schemes [5], [15], [16], a node steers its antenna at least (360 0 /θ 0 ) times to scan and notify its entire neighborhood, which introduces significant sweeping delay [17].Moreover, none of the above-mentioned CSMA-based schemes completely resolve the issues of deafness, hidden terminal, and capture effect [6]-[8], [10], [13], [18].Therefore, they are not suitable for directional communication.The TDMA (time division multiple access) schemes are widely used for directional communication since they can provide a conflict-free transmission schedule and avoid deafness and capture effect [6]-[8], [10]-[14], [18], [19].TDMAbased schemes also offer a better QoS (quality of service) support than random access-based schemes since they reserve a guaranteed period of time for each node to access the channel [19], [20].However, TDMA-based schemes can introduce large overhead and delay and are unable to adapt to topology changes in a multi-hop network in real-time [21], as discussed below.