Interference Evaluation of Bluetooth and IEEE 802.11b Systems

The emergence of several radio technologies, such as Bluetooth and IEEE 802.11, operating in the 2.4 GHz unlicensed ISM frequency band, may lead to signal interference and result in significant performance degradation when devices are colocated in the same environment. The main goal of this paper is to evaluate the effect of mutual interference on the performance of Bluetooth and IEEE 802.11b systems. We develop a simulation framework for modeling interference based on detailed MAC and PHY models. First, we use a simple simulation scenario to highlight the effects of parameters, such as transmission power, offered load, and traffic type. We then turn to more complex scenarios involving multiple Bluetooth piconets and WLAN devices.     

STUDY OF RADIO DEVICES ON 2.4GHZ ISM BAND IN PHYSICAL PHASE

In the unlicensed 2.4GHz ISM band,there is not only IEEE 802.11 wireless systems being used,but also some other devices,such as residential microwave oven,Bluetooth devices,and cordless phone.All these devices that are not used for the data communica- tions cause unintentional interference that will degrade the WI-FI system.In this paper,the transmission powers for common RF devices are measured and the SIR(signal-to-interference ratio)of different interferers to Wi-Fi is also studied.With this informati...     

High-rate wireless personal area networks

This article presents an overview of high-rate wireless personal area networks, its targeted applications, and a technical overview of medium access control and physical layers, and system performance. The high-rate WPANs operate in the unlicensed 2.4 GHz band at data rates up to 55 Mb/s that are commensurate with distribution of high-definition video and high-fidelity audio. An industry effort to create a MAC and PHY layer standard specification for high-rate WPANs has been ongoing in the IEEE 802.15.3 High Rate WPAN Task Group     

A new role-switching mechanism optimizing the coexistence of?bluetooth and Wi-Fi networks

Unlicensed ISM band is used by various wireless technologies. Therefore, issues related to ensuring the required efficiency and quality of operation of coexisting networks become essential. The paper addresses the problem of mutual interferences between IEEE 802.11b transmitters (commercially named Wi-Fi) and Bluetooth (BT) devices. An optimization approach to modeling the topology of BT scatternets is introduced, resulting in more efficient utilization of ISM environment consisting of BT and Wi-Fi networks. To achieve it, the Integer Linear Programming approach has been proposed. Example results presented in the paper illustrate significant benefits of using the proposed modeling strategy.     

Design and implementation of a MAC controller for the IEEE802.11 wireless LAN

IEEE 802.11 wireless LANs have a tremendous market potential, as they support high data rates, work in the world-wide licence free 2.4 GHz ISM band and have high performance in terms of range and power consumption. Hence, the development of a communication processor that supports the IEEE 802.11 MAC functions has a significant potential, making very important the concept of having an ASIC ‘right from the first time’, in order to minimize development cost and to meet short time-to-market requirements. This paper presents the methodology of developing such a component with emphasis on the rapid prototyping approach. The chip architecture, which is based on an ARM processor core, is described in detail, focusing on the implementation of the protocol functions using custom hardware modules. Finally, the paper presents experimental results on the ASIC implementation.     

短距离低功率无线通信接入系统

短距离低功率无线通信接入技术主要集中在物理层和媒体访问控制（MAC）层,包括蓝牙、超宽带（UWB）和Wi-Fi等。蓝牙是链接近距离设备的电缆数据传送的辅助技术;UWB作为窄脉冲无线电技术链接众多电子设备,提供宽带无线接入的灵活性和移动性;Wi-Fi给快速接入设备和WLAN内移动设备提供无线链接,用于较长距离链接,支持一定功率的移动终端接入。短距离低功率无线通信接入系统的标准化进程非常快,辅助标准多,但目前仍以蓝牙和Wi-Fi为主。     

对IEEE802.15.4抗干扰性能的改进

概述2.4GHz无线接收器物理层规范,并提出了一种改善IEEE 802.15.4在2.4GHzISM频段的抗干扰性能的技术,验证结果表明该技术满足接收要求,且具对IEEE802.11b/g等有较高的抗干扰性.     

An Efficient Frame Aggregation and Block-ACK Scheme for 60 GHz Short-Range Point-to-Point Transmission

The exploitation of the 60 GHz band is a very promising approach to fulfill the rapidly increasing data rate requirement of wireless indoor communication. One important 60 GHz application is the short-range point-to-point data transmission with Ultra-High-Rate (UHR, up to 10 Gbps) (Krone et al. in International Journal of Microwave and Wireless Technologies, 2011, 189–200). The design of such high data rate systems is very challenging. Except for Analog-Front-End (AFE) and physical layer (PHY) designs, the Medium Access Control (MAC) layer design is also crucial for the achievable system throughput. Among the MAC functionalities, the acknowledgment (ACK) mechanism is a very important component affecting the transmission efficiency and reliability. In this paper, a Hybrid Dynamic Frame Aggregation and Block-Acknowledgment (HD-FABA) scheme is proposed, which enables large-scale frame aggregation and can achieve significant ACK overhead reduction compared to the existing schemes. A theoretical model is developed for throughput analysis, which is verified by packet-level simulation. Both theoretical- and simulation results show that the HD-FABA scheme allows a number of MAC parameters to be optimized according to the PHY conditions (e.g. BER), leading to much higher throughput than with the state-of-the-art scheme.     

Coexistence of 2.4 GHz sensor networks in home environment

The IEEE 802.15.4 is one of the low-layer communication standards for personal area networks(PANs) and wireless sensor networks(WSNs),which may be interfered by other wireless devices in the industrial,scientific and medical(ISM) frequency bands,especially in home environment,such as devices of IEEE 802.11b,Bluetooth,cordless telephone,and microwave oven radiation.This article examines the mutual interference effects of 2.4 GHz devices widely deployed at home,via both theoretical analysis and real-life expe...     

Interference aware Bluetooth scatternet (re)configuration algorithm IBLUEREA

The paper presents a new algorithm IBLUEREA, which enables reconfiguration of Bluetooth (BT) scatternet to reduce mutual interferences between BT and Wi-Fi (IEEE 802.11b) networks operating on the same area. IBLUEREA makes use of proposed procedure for modeling ISM environment around a given BT scatternet. The mechanism is based on estimation of the probabilities of successful (unsuccessful) frame transmissions. This determination is useful to take a decision concerning co-existence of technologies which operate in the same ISM band (here Bluetooth and IEEE 802.11b).     

Protocols and architectures for channel assignment in wireless mesh networks

The use of multiple channels can substantially improve the performance of wireless mesh networks. Considering that the IEEE PHY specification permits the simultaneous operation of three non-overlapping channels in the 2.4 GHz band and 12 non-overlapping channels in the 5 GHz band, a major challenge in wireless mesh networks is how to efficiently assign these available channels in order to optimize the network performance. We survey and classify the current techniques proposed to solve this problem in both single-radio and multi-radio wireless mesh networks. This paper also discusses the issues in the design of multi-channel protocols and architectures.     

IEEE 802标准分析

文章分析IEEE 802标准，重点从无线、有线，以及异构（无线有线的混合）方面比较了这些标准的PHY层和MAC层的异同点。依据目前的研究现状和应用前景，对IEEE 802标准中相应的关键技术进行简析，并在此基础上展望了未来宽带无线接入技术的发展方向。     

Bit error rate analysis of Wi-Fi and bluetooth under the interference of 2.45 GHz RFID

IEEE 802.11b WLAN (Wi-Fi) and IEEE 802.15.1 WPAN (bluetooth) are prevalent nowadays, and radio frequency identification (RFID) is an emerging technology which has wider applications. 802.11b occupies unlicensed industrial, scientific and medical (ISM) band (2.4-2.483 5 GHz) and uses direct sequence spread spectrum (DSSS) to alleviate the narrow band interference and fading. Bluetooth is also one user of ISM band and adopts frequency hopping spread spectrum (FHSS) to avoid the mutual interference. RFID can operate on multiple frequency bands, such as 135 KHz, 13.56 MHz and 2.45 GHz. When 2.45 GHz RFID device, which uses FHSS, collocates with 802.11b or bluetooth, the mutual interference is inevitable. Although DSSS and FHSS are applied to mitigate the interference, their performance degradation may be very significant. Therefore, in this article, the impact of 2.45 GHz RFID on 802.11b and bluetooth is investigated. Bit error rate (BER) of 802.11b and bluetooth are analyzed by establishing a mathematical model, and the simula-tion results are compared with the theoretical analysis to justify this mathematical model.     

Interference mitigation in wireless sensor networks using dual heterogeneous radios

Scalability is one of the most important features that future wireless sensor networks (WSNs) should provide, and clustering is widely considered as a viable approach for high scalability. In the cluster-based architecture, the cluster heads play a key role in relaying messages between the sensor nodes and the sink. While the cluster heads are involved in both intra-cluster and inter-cluster communication, the latter typically requires transmission over much longer distance than the former. In this paper, we consider a scenario in which each cluster head is equipped with dual radios: IEEE 802.15.4 and IEEE 802.11 for intra-cluster and inter-cluster communication, respectively. IEEE 802.11 links between the cluster heads and the sink provide a high capacity backbone for large-scale WSNs. IEEE 802.15.4 and IEEE 802.11 share a lot of similarities including CSMA/CA MAC. Their operating spectrum also overlaps at the 2.4 GHz ISM band, and this may cause interference. We first experimentally measure how severe the interference can be, when two radios are concurrently used in a WSN. We, then, propose an interference mitigation solution which relies on adaptive aggregation of packets and adaptive transmission scheduling. Through prototyping and experimental evaluation, we show that the proposed scheme significantly reduces the interferences between the two types of radios.     

无线局域网在蓝牙干扰下的性能分析

IEEE802.11b是目前最主要的无线局域网组网方式,与蓝牙技术分享同一频段。通过建立两者的数据帧相互干扰的概率模型,从物理层与网络层两方面定量地分析了蓝牙设备对无线局域网整体性能的影响,为实际中无线局域网的建立提供了参考。     

A Self-Adaptive Spectrum Management Middleware for Wireless Sensor Networks

The vision of the Internet of Things, wherein everyday objects are embedded with smart wireless sensor devices, is making these sensor devices increasingly pervasive. As the density of their deployment in overlapping or adjacent areas increases, the contention for the unlicensed 2.4GHz ISM band will also increase. To deal with the crowded spectrum, nodes must use the channels more judiciously and be able to adapt by detecting and switching to the most available channel. The SAS middleware that we have developed, is a self-adaptive spectrum management middleware for wireless sensor networks that enhances single-frequency MAC protocols with multi-frequency capability, without any change in hardware. It allows a single-frequency MAC protocol, like B-MAC, to automatically adapt to the least congested physical channel at runtime. SAS supports a combination of receiver-initiated and sender-initiated schemes to decide when to switch the channel and which channel to switch to. We have implemented the B-MAC protocol integrated with SAS in TinyOS 2.1 on TelosB sensor devices and evaluated its performance on the conditions of varied data flows and the interference produced by a jammer. The results demonstrate that the integrated B-MAC protocol outperforms B-MAC in terms of packet reception ratio, system throughput, average packet delay, and energy consumption.     

Coexistence mechanisms for interference mitigation in the 2.4-GHz ISM band

Wireless technologies sharing the same frequency band and operating in the same environment often interfere with each other, causing severe decrease in performance. We propose two coexistence mechanisms based on traffic scheduling techniques that mitigate interference between different wireless systems operating in the 2.4-GHz industrial, medical, and scientific band. In particular, we consider IEEE 802.11 wireless local area networks (WLANs) and Bluetooth (BT) voice and data nodes, showing that the proposed algorithms can work when the two systems are able to exchange information as well as when they operate independently of one another. Results indicate that the proposed algorithms remarkably mitigate the interference between the IEEE 802.11 and BT technologies at the expense of a small additional delay in the data transfer. It is also shown that the impact of the interference generated by microwave ovens on the IEEE 802.11 WLANs performance can be significantly reduced through the mechanisms presented.     

2.4GHz无线技术标准及ZigBee抗干扰性能

介绍了ZigBee和其他几种工作于2.4GHz ISM频段的短距离无线通信技术标准,Wi-Fi、蓝牙和无线USB,对ZigBee本身的抗干扰性能以及与其他无线技术的共存进行了分析,讨论了如何保证ZigBee避免干扰和改善其共存性能.     

高速率无线个人域网(WPAN)

未来的无线通信系统大到覆盖全球的卫星网，小到个人域网。高速无线个人域网（WPAN）工作在不需许可证2.4GHz频段，最高速率可达55Mbit/s。本文阐述了WPAN的基本概念、目标应用以及媒体接入控制（MAC）层与物理层（PHY）的标准情况，还与无线局域网（WLAN）进行了比较。     

PAINT: Priority aware interference mitigation techniques for improving coexistence in home area networks of smart grid

As smart grid (SG) home area networks (HANs) communicate with various smart devices such as meters, sensors, and actuators on a 2.4‐GHz unlicensed band, the coexistence of different wireless technologies in such networks is a common phenomenon due to the overlapping of channels. In this research, homogeneous and heterogeneous interference are considered to address the coexistence problem in smart utility networks (SUNs). The homogeneous interference is mitigated by utilizing the contention free period (CFP) and the contention access period (CAP) of the MAC layer superframe of IEEE 802.15.4g designed for SUNs. This frame is used to get access for the channel. For this, a slotted CSMA/CA algorithm is used for various priority levels of data with adjustable backoff period (BP) and clear channel assessment (CCA) period in order that nodes (devices) with high priority can achieve high probability of channel access. By modeling the proposed scheme using the Markov chain, the exactness of the proposed scheme is assessed based on throughput, channel access delay, energy consumption per bit, and probability of successful data transmission and collision. A performance evaluation of the proposed scheme is further investigated by comparing it with the existing scheme PA‐MAC. In addition, a channel switching mechanism is explored to mitigate the heterogeneous interference with the help of a Naive Bayes classifier prediction. Finally, the prediction indicates that by choosing the non‐coexisting and the non‐overlapping channel, the proposed channel switching mechanism effectively mitigates the heterogeneous interference.