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This study evaluates the performance of a practical IEEE 802.15.4/4e/4g low-rate (LR) wireless personal area network (WPAN) with multiple physical (PHY) layers and multi-hop capabilities for smart utility networks, machine-to-machine networks and other advanced sensor networks. The proposal includes realistic design considerations addressing demands of practical applications, country-specific regulatory requirements and technical specification in international standards. A cross-layer open system interconnection model from the application, transport, network, medium access control, down to the multiple PHY layers is constructed based on the specification in IEEE 802.15.4 LR-WPAN and other layer-specific standards. Employing the cross-layer model, extensive computer simulations were conducted to investigate the performance of the LR-WPAN system in this application domain. As a result, the authors have successfully verified the simulated achievable average throughput in both PHY layer designs, multi-rate and multi-regional frequency shift keying (MR-FSK) and multi-rate and multi-regional orthogonal frequency division multiplexing (MR-OFDM) with the theoretical throughput by calculation. Secondly, in a multi-PHY environment with the presence of 30 interferer devices, throughput degradation of the victim system is observed within 30%. Furthermore, when interferer devices transmit frames with interval beyond 1 s, the degradation to the victim system becomes negligible. Thirdly, MR-FSK PHY has a simpler design with higher energy-efficiency, whereas MR-OFDM PHY is more complicated with more resilience to interference. They have found an interference tolerance capability difference of 15 dB between the MR-FSK and MR-OFDM systems. Fourthly, comparing with their single-hop counterparts, multi-hop systems have lower average throughput in MR-FSK by 25% and MR-OFDM by 10%. Finally, comparing with networks with periodical beacon transmissions, asynchronous networks have more inferior average throughput of 20% in MR-FSK and 3% in MR-OFDM, with the advantage of longer battery lifespan.

This article reports on the technical design and analysis of an interference management protocol that enables interference avoidance among multiple PHY layer designs in the recently completed IEEE 802.15.4g standard for smart utility networking (SUN). The IEEE 802.15.4g system employs three alternate PHY layer designs for enhanced SUN implementation and deployment targeting different market segments. First, SUN is introduced from different perspectives concerning technology, regulation, and the standardization process. Updates on the IEEE 802.15.4g standardization activities, the SUNrelated rules and regulations, and a summary of system design are presented. Next, the interference management protocol for multi-PHY-layer design in a single network is described and discussed. The impact of interference due to coexisting multiple PHY layer designs is highlighted. The operational procedure and mechanism of the management protocol, known as Multi-PHY Management (MPM), are then described. Finally, performance analysis in the presence of MPM is provided and discussed to justify its significance. It is anticipated that in the near future, this interference management approach will be put to field test and then deployed to provide solutions to mitigate interference among different PHY layer designs in SUN.

This article provides an overview of technical design considerations for IEEE 802.15.4m LRWPAN operating in TVWS. We summarize and discuss TVWS regulatory requirements and LRWPAN applications, the two major driving forces motivating the formation of the new IEEE 802.15.4m standard. These forces define the criteria necessary for consideration during IEEE 802.15.4m system design to meet regulatory requirements and optimize performance. First, system design is presented from the perspective of LR-WPAN channelization with reference to the TV channel plan. Next, design considerations for network architecture and topology are discussed by relating the architecture requirement in TVWS regulations to that in the legacy IEEE 802.15.4 standard. Third, the PHY and MAC layer designs, which are crucial for meeting the criterion of optimizing LR-WPAN performance to support potential applications, are studied. In the PHY layer, the existing design in IEEE 802.15.4 is listed and discussed with regard to its applicability and reusability in TVWS. In the MAC layer, two functional entities, the TVWS operation-enabling feature and the dynamic frequency-band switching mechanism, are discussed with respect to their necessity and practicality for performance enhancement.

This paper presents the network performance analysis of a low energy IEEE 802.15.4/4e/4m LR-WPAN operating in TV White Space. An energy-efficient mechanism optimizing the tradeoff between device sleep time and synchronization strategy is utilized to reduce the total power consumption in a non-beacon-enabled network. To evaluate the performance of the network, we have modeled a cross-layer system starting from the application, transport, network layers, to the MAC layer where the energy-efficient mechanism resides, to the PHY layer where the FSK PHY resides, down to the propagation channel where the VHF/UHF channels applies. Extensive computer simulations were conducted to investigate the performance of this low energy LR-WPAN system. As a result, we have found that a device may consume up to 40% and 2% of its total operation time to perform channel scanning and transmission, respectively. Applying the proposed energy-efficient mechanism, the achievable reduction of channel scanning time and transmission time are 20% and 1% respectively. We have also observed that the average residual battery capacity can be most effectively preserved when the number of devices in the network reaches approximately 30.

This paper proposes an energy-efficient beaconless synchronization mechanism for SUN operating in the TVWS. From the aspects of fulfilling the pervasive yet stringent requirements of low-energy wireless meters and TVWS regulations, the proposed mechanism is able to prolong battery lifespan beyond the required level for wireless smart meters, and is compliant to the specific network architecture and communication protocols demanded by the TVWS rules. In the MAC layer, a novel design for low duty cycle beaconless synchronization/data exchange is specified. In the PHY layer, the transceiver and realistic channel models applicable to the IEEE 802.15.4g SUN is constructed. Actual data from chip vendors of the wireless meter industry are also included to facilitate a more practical investigation. All the above are combined for performance evaluation to quantify the energy-efficiency and error performance of the proposed mechanism. As a result, it is found that the proposed mechanism enables battery lifespan of more than 10 years in most typical cases. For the system to achieve a ten-year battery lifespan at data transmission interval of 15 minutes, it is recommended that the system duty factor to be controlled in the order of 10−4, and that transmitted data frames to be limited within the length of 50 octets.

60 GHz millimeter wave technology has become an attractive solution for wireless communication in the most recent market. In the draft of IEEE 802.11ad standard, two modulation schemes are being considered in the design of physical (PHY) layer, namely, Single-Carrier (SC), and Orthogonal Frequency Division Multiplexing (OFDM). In this paper, the error performances of both coded modulation schemes under different channel models with hardware impairment are investigated. This hardware impairment includes non-linear distortion induced by 60 GHz power amplifier (PA) and phase noise of 60 GHz Phased Locked Loop (PLL) circuit. The channel models include Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) conference room models. Simulation results demonstrate that OFDM requires a much higher back-off power than SC to achieve the system requirement. In a realistic 60GHz channel based on measurements provided by 802.11ad, OFDM has gained better performance than SC with hardware impairment under NLOS situation using directional antennae.