Performance Analysis of a Multi-Hop IEEE 802.15.4g OFDM System in Multi-PHY Layer Network

This paper presents the performance analysis of an IEEE 802.15.4g multi-hop orthogonal frequency division multiplexing (OFDM) system in a network with multiple physical (PHY) layer design. Identified usage models for the IEEE 802.15.4g standard are low energy wireless sensor network and smart grid/utility network applications. For that, a total of three PHY layer designs under a unified medium access control (MAC) are specified to address different market segments. The multi-PHY layer architecture has an advantage of covering a wide range of pervasive use case scenarios, at the expense of inter-PHY interference (IPI) among respective PHY layers. This paper focuses on the OFDM PHY that promises high data rate and superior propagation performance. To enable optimized operation in the targeted applications, a multi-hop MAC layer design is specified to extend the operating range of the network, while low energy features are designed to increase energy efficiency of the system. Additionally, an IPI mitigation technique is also developed to combat IPI generated from the interfering network. As a result, it is found that the average throughput of a multi-hop OFDM network is 8% lower than that of a single-hop OFDM network, but with larger achievable operating range. Secondly, with the proposed IPI mitigation technique, no degradation among devices with different PHY layer designs is observed to take place. Thirdly, with the energy-efficient non-beacon-enabled mode, devices are consuming less power, at the expense of immunity reduction against interferer.