Data Rate Wireless Personal Area Research Articles

Design of Eight Parallel 512-Point MDF FFT/IFFT Processor for WPAN Applications

This paper presents a high-speed FFT algorithm for high data rate wireless personal area network applications. In a wireless personal area network, the FFT/IFFT block leads the major role. Computational requirements of FFT processors are a heavy burden in most real-time applications. From the previous work, it can be recognized that most of the FFT structures follow the divide and conquer algorithms, which improve the computational efficiency. In the proposed model, a new design of 512-point FFT/IFFT processor is derived by mixed approach for a Radix-26 algorithm, which has been presented and implemented using the Eight Parallel Multipath Delay Feedback (MDF) architecture. In this work, three distinct complex multiplication approaches are derived; from the analysis, a mixed approach has been proposed to reduce the multiplier complexity and also the equivalent normalized area. The proposed design is compiled and simulated with 90[Formula: see text]nm CMOS technology optimized for a 1.2[Formula: see text]V supply voltage. The proposed Mixed Radix-26 algorithm has been verified and validated using existing architectures. It has been found that the proposed mixed approach for Radix-26 algorithm reduces the normalized area by 8.603% compared with verified architectures. Also, the multiplier complexity is reduced by more than 33% using Canonical Signed Digit constant multiplier. The proposed architecture is suitable for applications like OFDM based WPAN applications at high data processing rates.

The \"Rap\" on ROF: Radio over Fiber Using Radio Access Point for High Data Rate Wireless Personal Area Networks

A wireless personal area network (WPAN) allows the wireless devices in a user's personal workspace to be connected to the network. Due to the huge increase in both the number of wireless communication subscribers and the bandwidth required per customer with the proliferation of smart devices, the low-frequency radio spectrum is becoming overcrowded. A natural solution for future WPANs is to migrate to higher radio frequency (RF) carriers [1]. High data-rate WPANs may be implemented based on the Federal Communications Commission (FCC) compliant ultrawideband (UWB) standard [2] or on the IEEE 802.15.3c standard [3]. The UWB signal was defined by the FCC as a signal having a bandwidth larger than 20% of the carrier frequency or a bandwidth of at least 500 MHz in the 3.1-10.6-GHz band; IEEE 802.15.3c relies on a carrier frequency in the 60-GHz license-free industrial, scientific, and medical (ISM) band. The implementation of both the UWB standard and the IEEE 802.15.3c standard faces certain challenges, which may be tackled with the aid of radio over fiber (ROF) techniques that employ optical generation of the wireless signal. ROF networking solutions have been proposed for future high-bandwidth wireless communication systems that rely on the transmission of RF signals between the base station (BS) and remote antennas [1], [4]-[8].

IJIREEICE - Electrical, Electronics, Instrumentation and Control

Wireless sensor networks represent a key technology enabler for enhanced health care and assisted living systems. Recent standardization efforts to ensure compatibility among sensor network systems have produced the IEEE 802.15.4 standard, which specifies the MAC and physical layer behaviour. Energy and network life time are two critical factors for WSN performance. IEEE 802.15.4 is a standard used for low data rate Wireless Personal Area Networks (WPANs). Medium Access Control layer (MAC) of IEEE 802.15.4 plays an important role in the performance of Wireless Sensor Network (WSN). The unique feature of this MAC layer is the superframe structure, which allows devices to access channels in a Contention Access Period (CAP) or Collision Free Period (CFP) and use beacon based synchronization mechanism. In this paper, we propose a cross-layer framework to prolong the network lifetime, to improve the energy and to lower the latency of WSNs based on the IEEE 802.15.4/ZigBee standards. To cover all the scenarios, we have considered hierarchical topology and peer to peer beacon enabled network. The performance metrics are evaluated using simulation results.

IMPORTANT: Integrating Multi-rate caPability into Opportunistic Routing in uwb-based Ad hoc NeTworks

Ultra-wideband (UWB) communications has emerged as a burgeoning technology for high data rate wireless personal area networks (WPANs). In this paper, we exploit the integration of rate assignment into opportunistic routing under a required QoS, i.e., end-to-end packet error rate (PER), for improving the performance of UWB-based WPANs. Opportunistic routing has been proposed for ad hoc networks. In this type of routing protocols, instead of determining a static path ahead of time, the path is constructed dynamically. The protocol exploits the broadcast nature of wireless communications by allowing packet forwarding to be done by the closest recipient to the destination. Several works showed that opportunistic routing improves network performance. None of these works studied the integration of rate assignment into opportunistic routing while satisfying a target QoS. In this paper, we formulate and study this integration. In our setup, we aim at determining the required number of retransmissions in opportunistic routing and the transmission rate in each retransmission such that the required delivering time for a sent packet is minimized while at the same time a certain end-to-end PER is satisfied. We show that this problem is NP-hard. Accordingly, we propose an approximate solution called IMPORTANT. Extensive simulations over a UWB-based WPAN show that IMPORTANT achieves high performance relative to different techniques (21–48% throughput improvement).

Resource Allocation in High Data Rate Mesh WPAN: A Survey Paper

IEEE 802.15.3 High data rate wireless personal area networks (HDR WPANs) have been developed to communicate with devices within 10 m at high speed. A mesh network made up of a parent piconet and several child piconets can support multi-hop communications. Wireless mesh networks (WMNs) have been expected to be the ultimate solution for the next decade wireless networking, showing rapid progress and many new inspiring applications. The international standardization organizations formed working groups to address the problem of standardization for WMNs. These groups were the IEEE 802.15.5 (mesh extensions for WPANs),the IEEE 802.11s (mesh extensions for WLANs), and the IEEE 802.16a (mesh extensions for WiMAX). The IEEE 802.15.5 standard is the standard which defines specifications for including multi-hop functionality in the legacy 802.15.3 and 802.15.4 low data rate (LDR) WPAN networks. The impetus for a WPAN to operate in a mesh topology is to increase the network coverage without increasing the transmit power, to increase the route reliability via route redundancy, self-configuration, and efficient use of device battery life. In the case of meshed WPANs, multiple WPAN clusters compete for channel time in a shared superframe. Therefore, it is essential to determine the channel time requirements of each cluster with a certain number of devices and to determine how these clusters can compete to the shared channel time. In this paper, we investigate the different resource allocation mechanisms related to the meshed HDR WPANs for the 802.15.3 and the 802.15.5 standards. We introduce the single hop and the multi-hop IEEE 802.15.3 WPAN architectures. This is followed by the introduction of the IEEE 802.15.5 standard that provides the mesh capabilities for extending the coverage area of HDR WPANs. The current on-going research issues for resource allocation, including beacon interference, reservation collision etc., in both meshed 802.15.3 and 802.15.5 are alluded to.

Validation of Statistical Channel Models for 60 GHz Radio Systems in Hospital Environments

Statistical channel models for 60 GHz communications systems in hospital environments are validated using channel capacity and throughput of a physical layer as figures of merit. The channel models are validated by comparing the performance figures with channels from the measurements and the channel models. The throughput evaluation is based on system specifications given by the IEEE 802.15.3 c standard for high data rate wireless personal area networks, namely orthogonal frequency division multiplexing and single carrier transmissions. The channel capacity serves as a metric of the potential of the two transmission schemes since it defines the upper bound of the throughput. The capacity is derived based on the signal formats of the transmission schemes. The capacity shows that 97 % of the measurement results are within 2σ range of the modeled results. The throughput shows that the channel models predict the maximum achievable throughput of the measured channels precisely, while the mean throughput in some cases shows difference because of the interpolation effect of the small-scale fading in the statistical channel models. Due to the interpolation effect, the channel model is more suitable for a precise analysis of the outage performance than the measurements where the number of channel samples is limited and the worst faded channels are not necessarily included.

에너지 효율성 향상을 위하여 방향성 메시징을 사용하는 수정된 지그비의 설계 및 구현

ZigBee is the low power, low cost and low data rate wireless personal area network(LR-WPAN) standard. The Directed-Messaging is the protocol which improves the energy efficiency through reducing the redundant message transmission by transmitting messages with directional information toward the specified sub-network area in wireless sensor network using broadcasting. In this paper, we design and implement the experimental grid sensor network using ZigBee modified by the Directed-Messaging for the energy efficiency improvement. The experimental sensor network in this paper is configured with Nano24 supporting the ADV message and the routing management module modified to use the directional information. The energy efficiency improvement of the experimental sensor-network by evaluating the experimental results according to transmitting ADV message.

An incrementally deployable energy efficient 802.15.4 MAC protocol (DEEP)

The IEEE 802.15.4 is a standard that specifies the physical layer and media access control for low data rate wireless personal area networks (WPANs). The standard is intended to provide connectivity to mobile devices with storage, energy, and communication constraints that can be used in many industrial, military and civilian application areas. These mobile devices (usually sensors) and actuators are equipped with a radio transceiver, a microcontroller, and a source of energy which is usually a battery. In order to extend the lifetime of a WPAN using the beacon-enabled 802.15.4 standard, we propose an incrementally deployable and energy efficient 802.15.4 MAC protocol (DEEP) for beacon-enabled sensor networks. The implementation of our protocol requires modifications to the superframe guaranteed time slot (GTS) distribution mechanism to reduce energy consumption in the network by reducing the size of broadcast beacons. We implement DEEP through simulations and also using real sensors. For the simulations, we implemented our protocol using Omnet++, and tinyOS and the nesC language were used for the experiments. Our results show that DEEP reduces energy consumption up to nearly 50% when seven devices allocate guaranteed time slots descriptors during normal communication. We also show that DEEP is backward compatible and can be incrementally deployed to extend the lifetime of the network: a partial deployment of DEEP leads to proportional improvements in the network energy savings.

Performance of an efficient heuristic scheduling algorithm for MPEG-4 traffic in high data rate wireless personal area network

In this research, the authors study the impact of a controlling parameter on system performances of our previously proposed heuristic channel-aware scheduling algorithm. In addition, parameter optimisation for a combined performance measure is also discussed. The investigation is carried out through numerical simulations via ns-2. When compared with other algorithms, the proposed algorithm uniformly shows the best performance, with the performance gain being more evident for bad channel. The findings are useful for system designers.

A CMOS 802.15.4a transmitter for sub-GHz application

A bi-phase modulated sub-GHz ultra-wideband (UWB) transmitter is designed and tested with standard 0.5-μm CMOS technology. The maximum power consumption is 2.4 mW, when the pulse repetition frequency is 20 MHz with 420-MHz center frequency. The proposed sub-GHz CMOS UWB transmitter complies with IEEE 802.15.4a standard for low data rate wireless personal area network applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26136

Cross-layer design for efficient resource utilization in wimedia UWB-based WPANs

Ultra-WideBand (UWB) communications has emerged as a promising technology for high data rate Wireless Personal Area Networks (WPANs). In this article, we address two key issues that impact the performance of a multihop UWB-based WPAN: throughput and transmission range. Arbitrary selection of routes in such a network may result in reserving an unnecessarily long channel time, and hence low network throughput and high blocking rate for prospective reservations. To remedy this situation, we propose a novel cross-layer resource allocation design. At the core of this design is a routing technique (called RTERU) that uses the allocated channel time as a routing metric. RTERU exploits the dependence of this metric on the multiple-rate capability of an UWB system. We show that selecting the route that consumes the minimum channel time while satisfying a target packet delivery probability over the selected route is an NP-hard problem. Accordingly, RTERU resorts to approximate path selection algorithms (implemented proactively and reactively) to find near-optimal solutions at reasonable computational/communication overhead. We further enhance the performance of RTERU by integrating into its design a packet overhearing capability. Simulations are used to demonstrate the performance of our proposed solutions.

Interference Management and Rate Adaptation in OFDM-Based UWB Networks

Ultrawideband (UWB) communications has emerged as a promising technology for high data rate wireless personal area networks (WPANs). Several proposals for UWB-based WPANs have been made. One widely popular proposal was standardized by ECMA-368, and is based on OFDM. In this paper, we address one of the important aspects that impact the performance of this standard, namely interference management between different uncooperative beacon groups that operate simultaneously over the same area. We first propose an interference management distributed reservation protocol (IM-DRP) for OFDM-based UWB communications. IM-DRP aims at improving the throughput of an UWB WPAN by reducing interference between uncooperative beacon groups. We then integrate IM-DRP into the design of a rate adaptation strategy that exploits the multirate capability of OFDM-based UWB systems. Besides maintaining a target packet error rate, our proposed strategy attempts to reduce the required reservation time over a link, hence allowing more links to be simultaneously activated. This improves the overall network throughput. Simulations are used to demonstrate the performance gain of our proposed schemes.

A resource allocation strategy for meshed high data rate WPANs

In order to extend the operating space of single hop High Data Rate (HDR) Wireless Personal Area Networks (WPANs), the meshed configuration can be used for multi-hop functionality. Since the superframe is shared between multiple WPAN piconets for communication, with higher device density, the superframe capacity usually proves to be a bottleneck. Furthermore, when the superframe capacity is shared in a distributed fashion, issues of fairness in time allocation arises. In this paper we propose a centralized scheme for resource allocation specifically in meshed WPANs and induce an element of fairness in time allocation. Simulation results prove the effectiveness of the proposed approach.

Performance Analysis of Ultra Wideband Receivers for High Data Rate Wireless Personal Area Network System

For high data rate ultra wideband communication system, performance comparison of Rake, MMSE and Rake-MMSE receivers is attempted in this paper. Further a detail study on Rake-MMSE time domain equalizers is carried out taking into account all the important parameters such as the effect of the number of Rake fingers and equalizer taps on the error rate performance. This receiver combats inter-symbol interference by taking advantages of both the Rake and equalizer structure. The bit error rate performances are investigated using MATLAB simulation on IEEE 802.15.3a defined UWB channel models. Simulation results show that the bit error rate probability of Rake-MMSE receiver is much better than Rake receiver and MMSE equalizer. Study on non-line of sight indoor channel models illustrates that bit error rate performance of Rake-MMSE (both LE and DFE) improves for CM3 model with smaller spread compared to CM4 channel model. It is indicated that for a MMSE equalizer operating at low to medium SNR values, the number of Rake fingers is the dominant factor to improve system performance, while at high SNR values the number of equalizer taps plays a more significant role in reducing the error rate.

Centralised resource allocation policies for meshed high data rate wireless personal area networks

Multi-media applications with demanding throughput requirements often raise issues of capacity limitations in wireless networks. High data rate (HDR) wireless personal area networks (WPANs) can operate in a mesh configuration to extend from the legacy single-hop communication to multiple hops. Although the range of WPANs is increased in a mesh configuration, there are capacity constraints because the superframe time is shared by multiple piconet clusters instead of being dedicated for a single piconet cluster just like in the legacy single-hop case. Furthermore, the distributed superframe sharing can cause fairness issues because there is no mechanism to determine the requirement of each mesh piconet coordinator (MPNC) and monitor a fair allocation to each MPNC. Here, the authors propose a centralised resource allocation approach and define three resource allocation policies for meshed HDR WPANs. The proposed approach is augmented by a traffic estimation strategy to predict a suitable fraction of superframe time for each cluster. Simulation results prove the effectiveness of the proposed resource allocation policies and the fairness index is shown to increase upto 42% with the proposed approach in some cases.

Rex: A randomized EXclusive region based scheduling scheme for mmWave WPANs with directional antenna

Millimeter-wave (mmWave) transmissions are promising technologies for high data rate (multi-Gbps) Wireless Personal Area Networks (WPANs). In this paper, we first introduce the concept of exclusive region (ER) to allow concurrent transmissions to explore the spatial multiplexing gain of wireless networks. Considering the unique characteristics of mmWave communications and the use of omni-directional or directional antennae, we derive the ER conditions which ensure that concurrent transmissions can always outperform serial TDMA transmissions in a mmWave WPAN. We then propose REX, a randomized ER based scheduling scheme, to decide a set of senders that can transmit simultaneously. In addition, the expected number of flows that can be scheduled for concurrent transmissions is obtained analytically. Extensive simulations are conducted to validate the analysis and demonstrate the effectiveness and efficiency of the proposed REX scheduling scheme. The results should provide important guidelines for future deployment of mmWave based WPANs.

Cross-layer enhanced time scheduling for multi-band OFDM UWB networks

Multi-band Orthogonal Frequency Division multiplexing based Ultra Wide-band (MB-OFDM UWB) technology is one of the strong alternatives for high data rate wireless personal area networks (WPANs) with low power consumption. The capacity of such systems is degraded by multi-path fading, shadowing, multi-user interference and noise. To improve system capacity under these adverse effects, in this paper, we devise cross-layer time scheduling methods, Proportional Time Scheduling with Modiano Algorithm (PTS-MA) and Proportional Time Scheduling with Channel State Information (PTS-CSI), in which scheduling and link adaptation are performed using instantaneous bit error probability (IBEP) estimates obtained through Modiano's algorithm and our novel estimation technique, respectively. We evaluate the performance of the PTS schemes by using numerical experiments. Simulation results suggest PTS-CSI scheduler as the most promising candidate for practical MB-OFDM UWB WPANs with high capacity and fair throughput distribution.

Performance of IEEE 802.15.4 Clusters with Power Management and Key Exchange

The IEEE 802.15.4 specification is a recent low data rate wireless personal area network standard. While basic security services are provided for, there is a lack of more advanced techniques which are indispensable in modern personal area network applications. In addition, performance implications of those services are not known. In this paper, we describe a secure data exchange protocol based on the ZigBee specification and built on top of IEEE 802.15.4 link layer. This protocol includes a key exchange mechanism. We assume that all nodes are applying power management technique based on the constant event sensing reliability required by the coordinator. Power management generates random sleep times by every node which in average fairly distributes the sensing load among the nodes. Key exchange is initiated by a cluster coordinator after some given number of sensing packets have been received by the coordinator. We develop and integrate simulation model of the key exchange and power management technique into the cluster’s reliable sensing function. We evaluate the impact of security function and its periodicity on cluster performance.

Third-Party Handshake Protocol for Efficient Peer Discovery and Route Optimization in IEEE 802.15.3 WPANs

Designed for high data rate wireless personal area networks, the IEEE 802.15.3 medium access control (MAC) protocol fits well with emerging technologies like ultra-wideband. Peer discovery is essential in 802.15.3 piconets in w3:22 hich devices (DEVs) exchange MAC frames in a peer-to-peer manner. If two peer DEVs are unreachable, the standard peer discovery method will fail after unproductive backoff retransmissions, and a costly network layer routing is required. For DEVs uniformly distributed over the maximum coverage area of a piconet, such failures occur in up to 41.3% of intra-piconet peer discoveries. In this paper, we propose a novel third-party handshake protocol (3PHP) that provides more reliable and prompt peer discovery than the standard method. Especially, between directly unreachable DEVs within the same piconet, 3PHP replaces network layer routing by an efficient MAC layer forwarding that utilizes the available self-learning rate information to establish optimal routes. The mean peer discovery time for 3PHP is 100 µs lower than the standard method between directly reachable DEVs. More significantly, between directly unreachable DEVs within the same piconet, 3PHP has a much lower failure probability, and is up to 10 times faster than the standard method in establishing a peer-to-peer connection as the latter fails and network layer routing is invoked.

The application of iterative equalisation to high data rate wireless personal area networks

There is increasing demand for broadband wireless personal area networking devices, mainly fuelled by mobile multimedia applications such as wireless home networks. This paper investigates the suitability of iterative equalisation as a means of achieving low bit and packet error rates in a future high data rate personal area network standard. Baseband simulation results demonstrate the powerful ISI mitigation and error correcting performance of such receivers when operating in representative indoor wideband channels.