Operation Of IEEE Research Articles

TCP BBR-n: Increased throughput for wireless-AC networks

Google proposed a new TCP congestion control algorithm (CCA), Bottleneck Bandwidth and Round-trip propagation time (BBR) which has opened up new dimensions in congestion control. BBR tries to operate near Kleinrock’s operating point to avoid excessive queue formation at the bottleneck and to use the link bandwidth optimally. BBR creates a model of the network path by measuring the bottleneck bandwidth and minimum round-trip time (RTT) to maximize the delivery rate and minimize latency. BBR v2 is an updated version of BBR which addresses many shortcomings of the original BBR (BBR v1) such as interprotocol fairness, RTT fairness, and excessive retransmissions. However, BBR v2 has certain limitations in its operation in IEEE 802.11ac (Wi-Fi 5) networks. The default BBR v2 limits the throughput of Wi-Fi 5 and an increased latency has been observed. This is because the Wi-Fi 5 frame aggregation logic is underutilized and fewer frames are being sent to the Wi-Fi 5 interface. In this paper, we have proposed BBR-n (BBR new) which provides better throughput than the generic BBR v2 in the Wi-Fi 5 networks. Real-time experiments were performed over a physical testbed using Flent to confirm that BBR-n achieves over double throughput as compared to generic BBR v2 and reduced latency in networks as compared to pure loss-based variants such as Cubic and Reno.

Multi-Link Operation in IEEE 802.11be WLANs

The multi-link operation (MLO) is a new feature proposed to be part of the IEEE 802.11be Extremely High Throughput (EHT) amendment. Such feature represents a paradigm shift towards multi-link communications, as nodes will be allowed to transmit and receive data over multiple radio interfaces concurrently. To make it possible, the 802.11be Task Group has proposed different modifications in regards to nodes' architecture, transmission operation, and management functionalities. This article reviews such changes and tackles the question of how traffic should be distributed over multiple links, as it is still unresolved. To that end, we evaluate different load balancing strategies over the active links. Results show that in high load, dense and complex scenarios, implementing congestion aware load balancing policies to significantly enhance next-generation WLAN performance using MLO is a must.

Performance Analysis of Synchronous Multi-Radio Multi-Link MAC Protocols in IEEE 802.11be Extremely High Throughput WLANs

The representative media access control (MAC) mechanism of IEEE 802.11 is a distributed coordination function (DCF), which operates based on carrier-sense multiple access with collision avoidance (CSMA/CA) with binary exponential backoff. The next amendment of IEEE 802.11 being developed for future Wi-Fi by the task group-be is called IEEE 802.11be, where the multi-link operation is mainly discussed when it comes to MAC layer operation. The multi-link operation discussed in IEEE 802.11be allows multi-link devices to establish multiple links and operate them simultaneously. Since the medium access on a link may affect the other links, and the conventional MAC mechanism has just taken account of a single link, the DCF should be used after careful consideration for multi-link operation. In this paper, we summarize the DCFs being reviewed to support the multi-radio multi-link operation in IEEE 802.11be and analyze their performance using the Markov chain model. Throughout the extensive performance evaluation, we summarize each MAC protocol’s pros and cons and discuss essential findings of the candidate MAC protocols.

IEEE 802.11ba Wake-Up Radio: Performance Evaluation and Practical Designs

Featuring a long operation time to avoid frequent battery replacements, highly energy-efficient radios have shown their pivotal functions for low-power and battery-driven devices in supporting manifold Internet-of-Things (IoT) services. To this end, prolific systems for highly energy-efficient radios have been widely deployed, but they impose a critical challenge of sacrificed data rates to preclude the applications that both require high energy efficiency and high data rates. Recently, this challenge has driven the concept of equipping two radio-chains on a low-power device, known as the primary connectivity radio (PCR) and companion connectivity radio (CCR). The PCR supports high data rate transmissions, and switches to the sleeping mode when no data should be received. In this case, the CCR stays awake to monitor traffic, and wakes up the PCR when data requiring to be received arrives. However, to practice such a concept, sophisticated operations in the physical (PHY) layer and medium access control (MAC) layers are required. Consequently, the IEEE 802.11 Task Group “ba” (TGba) has been formed to launch the normative works since 2017. In the normative development, the most challenging issue lies in the design of a new frame structure especially the preamble sequence, by which the CCR in a station (STA) can efficiently synchronize with an access point (AP) and the PCR can be promptly waken up when an AP wishes to transmit data to an STA. To comprehend such a crucial foundation for the next generation low-power IoT devices, this paper provides comprehensive knowledge of state-of-the-art PHY/MAC operations of IEEE 802.11ba. Most importantly, a preamble sequence design for synchronization is further proposed for the new frames supported in IEEE 802.11ba. Through comprehensively evaluating the performance of different designs (in terms of data rate configuration and synchronization sequences), we justify the outstanding performance of the proposed design in terms of the synchronization error rate and packet error rate, to satisfy the urgent demands in the normative works of IEEE 802.11ba.

Learning-Based Spatial Reuse for WLANs With Early Identification of Interfering Transmitters

In this paper, a reinforcement learning-based spatial reuse scheme for wireless local area networks (WLANs) is proposed and analyzed. In this scheme, when an access point (or a station) overhears an on-going transmission, it decodes the information in the frame header to identify the transmitter and decides whether or not to exploit spatial reuse accordingly. Specifically, it decides whether to stop receiving the remaining part of the frame and start its own transmission or to refrain from channel access until the detected transmission finishes. Through the repeated update Q-learning (RUQL) algorithm, the agent learns the optimal decision in the sense of reducing the media access control layer delay. Moreover, we compare the proposed scheme with the spatial reuse operation in IEEE 802.11ax, which makes the spatial reuse decision only based on a binary identification of the detected interferer, i.e., whether it is in my cell or neighboring cells. The proposed scheme, however, treats different interferers differently for exploiting spatial reuse. From a theoretical perspective, we derive a theoretical bound on the gains in the value function, i.e., the discounted sum of delay, due to making non-binary identifications. Simulation evaluations confirm that the proposed scheme achieves high throughput by reducing the time of freezing backoff counter while not increasing the time of failed transmissions.

Transparent dual band antenna with μ‐negative material loading for smart devices

AbstractA dual‐band optically transparent antenna having two slotted circular rings with partial ground plane is proposed for smart applications. The antenna has circular split ring resonators (SRRs) array which offers negative refractive index properties to the resonator. The antenna is fed using microstrip feed line which is matched at 50 Ω. The conducting patch, partial ground plane and two circular SRRs are made up of transparent conducting thin film AgHT‐8 having transparency of above 80%. Substrate in the form of Plexiglas is used for making the antenna structure completely transparent. Metamaterial is incorporated for achieving acceptable values of antenna gain. The patch design is engineered for antenna operation in IEEE a/b/g/n frequency bands working at 2.4 GHz and 5.5 GHz, respectively. The size of the proposed transparent antenna is 35 × 35 × 1.84 mm3 with measured impedance bandwidth of 13.27% and 5.28% achieved for lower frequency band of 2.4 GHz and the upper frequency band of 5.5 GHz, respectively. The proposed antenna is useful for smart devices communicating over WLAN frequency bands without need of extra board space due to the optical transparency of antenna.

A novel method for mitigating the effects of dynamic coexistence on the operation of IEEE 802.15.4‐based mobile WSNs

AbstractWireless networks dynamically coexist when their transmission ranges overlap as a result of mobility. Mobile wireless sensor networks (WSNs) may suffer from significant degradation of performance due to the interference caused by dynamic coexistence, which is particularly critical for health monitoring WSNs. In this paper, we propose a novel method to detect and mitigate the harmful effects of dynamic coexistence on the operation of IEEE 802.15.4‐based mobile health monitoring WSNs. IEEE 802.15.4 uses the guaranteed time slots (GTS) mechanism to eliminate contention; however, successful transmissions cannot be guaranteed for coexisting WSNs. We show that using limited clear channel assessments at the beginning of the GTS enables the mobile WSNs to avoid collisions with minimum overhead. This method can also be used in combination with the previously proposed mechanisms for coexistence management. We analytically investigate the effects of using this method on the performance of the dynamically coexisting WSNs. We use OPNET simulation to investigate the coexistence of health monitoring WSNs and also to validate the proposed method. Our results indicate that using the proposed mechanism, 2–10 coexisting mobile WSNs with relatively high transmission rates (20–30% of maximum throughput) can achieve 20–90% higher rates of successful transmissions, with less than 10% increase in power consumption. Copyright © 2014 John Wiley & Sons, Ltd.

Performance evaluation for delay time estimation in IEEE 802.16m sleep mode

Frequent use of various mobile application services consumes a great amount of battery power in mobile devices. In order to satisfy user convenience and keep the portability of mobile devices, a power saving mechanism is essential for the success of mobile communication technologies. This paper evaluates performances of the power saving mechanism of IEEE 802.16m, one of the solutions for the fourth generation mobile communication technology. When a mobile device does not communicate with a base station, it temporarily shuts down communication-related modules and circuits in order to save the battery power. During that period, the device cannot listen to incoming traffic from the base station, which causes an inevitable delay at the expense of reducing power consumption. Arriving packets are transmitted only after the device enters either the awake mode or the listening window in the sleep mode. Four power saving mechanisms are examined in the simulation:1) fixed maximum operating parameters, 2) fixed minimum operating parameters, 3) moving average policy, and 4) exponential increase policy. To evaluate the performance of the sleep mode operation in IEEE 802.16m, an analytical model is developed for delay time based on M/D/1 queueing system. Performances of the power saving mechanisms are evaluated with Poisson and traffic models for five applications: WEB, FTP, GAME, VIDEO, and VOICE, which reflects real service environment.

WiFi 트래픽의 간섭환경에서 IEEE 802.15.4 노드의 프레임 전송 및 채널변경 방법

이 논문에서는 WiFi 트래픽으로 인해 IEEE 802.15.4 노드에서 프레임 전송에 장애가 발생할 때, IEEE 802.15.4 네트워크의 노드들을 새로운 채널에서 동작시키기 위한 프레임 전송방법과 특성에 연구되었다. WiFi 트래픽의 간섭에 대한 평가, 간섭이 적거나 없는 새로운 채널의 탐색 및 동작채널을 변경하기 위한 연구들에 대해 분석하였다. IEEE 802.11 네트워크와 중첩된 무선채널에서 IEEE 802.15.4 프레임의 전송지연과 CSMA-CA 알고리즘을 적용하지 않은 IEEE 802.15.4 프레임 전송시 프레임들의 충돌 및 IEEE 802.11 노드들의 동작에 대해 설명하였다. 충돌된 IEEE 802.15.4 프레임의 잔여부분을 사용하기 위해 프레임형식코드블럭들을 포함한 프레임의 전송방법이 제안되었다. 제안된 방법의 실험을 통해, 충돌시 프레임형식코드블럭들이 수신기에서 동기화되어 수신되는 현상을 관찰하고, IEEE 802.15.4 프레임에서 충돌을 겪는 위치, 프레임수신율에 대한 특성이 분석되었다. WiFi 트래픽의 간섭을 피하기 위해 IEEE 802.15.4 네트워크의 채널변경명령을 전송하고 응답을 얻기까지 걸리는 시간을 측정한 실험결과는 제안된 방법이 기존의 방법보다 개선된 성능을 나타낸다. In this paper, a frame transmission method to make IEEE 802.15.4 nodes run at a new channel and its characteristics are studied when they experience difficulties in transmission of frames due to WiFi traffic. The researches on evaluating the interference from WiFi traffic, searching for a new channel with little interference or not, and changing the operating channel are analyzed. In an wireless channel overlapped with IEEE 802.11 network, the transmission delay of IEEE 802.15.4 frames, the collision of frames in sending IEEE 802.15.4 frames without applying CSMA-CA algorithm, and the operation of IEEE 802.11 nodes are explained. A transmission method of frames including frame-formated code blocks in order to use the rest part of collided IEEE 802.15.4 frame is proposed. In the experiments of the proposed method, it is observed that frame-formated code blocks are synchronized and received by receivers in case of collision, and then the collided positions in IEEE 802.15.4 frame and the characteristics of frame reception rate are analyzed. The experimental results show that the performance of the proposed method is improved in comparison to an existing method when we measure the time taken to send a channel change command and get the response in order to avoid the interference from WiFi traffic.

A Distributed Scheme to Manage The Dynamic Coexistence of IEEE 802.15.4-Based Health-Monitoring WBANs

The overlap of transmission ranges between wireless networks as a result of mobility is referred to as dynamic coexistence. The interference caused by coexistence may significantly affect the performance of wireless body area networks (WBANs) where reliability is particularly critical for health monitoring applications. In this paper, we analytically study the effects of dynamic coexistence on the operation of IEEE 802.15.4-based health monitoring WBANs. The current IEEE 802.15.4 standard lacks mechanisms for effectively managing the coexistence of mobile WBANs. Considering the specific characteristics and requirements of health monitoring WBANs, we propose the dynamic coexistence management (DCM) mechanism to make IEEE 802.15.4-based WBANs able to detect and mitigate the harmful effects of coexistence. We assess the effectiveness of this scheme using extensive OPNET simulations. Our results indicate that DCM improves the successful transmission rates of dynamically coexisting WBANs by 20%-25% for typical medical monitoring applications.

A Throughput Model of IEEE 802.11aa Intra-Access Category Prioritization

In this paper the first saturation throughput model of an IEEE 802.11 network is presented, which includes the intra-access category prioritization introduced in the recently approved IEEE 802.11aa standard. This new feature was proposed to support finer grained prioritization of audio video streams in comparison to the existing Enhanced Distributed Channel Access (EDCA) function. The presented model implements different transmission probabilities for the primary and alternate voice and video queues. Additionally, it includes such features as virtual collision handling, backoff differentiation, and Arbitration Inter-Frame Space differentiation. The presented results show the difference in the operation of IEEE 802.11aa intra-access category prioritization and EDCA inter-access category prioritization. They also allow to derive several novel conclusions.

Performance Modeling of Energy Saving Mechanism Using Batch Operation in IEEE 802.16e

IEEE 802.16e specifies power saving standards for energy efficient communication of a mobile subscriber station. This paper investigates analytically and evaluate the performance of the sleep mode operation of IEEE 802.16e for the power saving class type -I. We analyze a sleep mode mechanism using batch service queueing system with multiple vacations and changeover time. It is observed that in the sleep mode, a mobile subscriber stations sleeps for a sleep window and wakes up to check the number of pending download packets. We study the overall message delay in the downlink channel and performance of mean number of packets in the queue, queueing delay and probability of blocking. Numerical results show that our proposed approach achieves better energy management.

Joint paging area and location update optimization for IEEE 802.16m idle mode

As mobile devices are becoming smaller and users are desiring a longer battery life, the advanced power conservation mechanism, the idle mode, which is an enhanced version of the legacy IEEE 802.16 system’s idle mode, was proposed and adopted in IEEE 802.16m. Idle mode operation in IEEE 802.16m provides a lower location update overhead as well as a more efficient multiple paging-group operation compared to the legacy idle mode operation. However, there is a tradeoff between paging and location update overhead in the multiple paging-group operation. To address this issue, the paging-group location update timer (PG_LU_TIMER) was adopted in IEEE 802.16m. However, the manner in which this parameter balances the paging overhead and the location update overhead and the optimal value of the parameter are outside the scope of the IEEE 802.16m standard description. The main contribution of this paper is validation and further optimization of the joint paging area and location update proposed in the IEEE 802.16m air interface through analytical modeling and simulation of multiple paging-group operation with the PG_LU_TIMER. Our simulation results show that the PG_LU_TIMER can jointly reduce the location update overhead and paging overhead by up to 80.3% and 82.3% respectively. Furthermore our analysis shows that the proposed location update mechanism can save up to 640 μJ of energy compared to the legacy idle mode location update model.

A stochastic model for beaconless IEEE 802.15.4 MAC operation

IEEE 802.15.4 is a popular choice for MAC/PHY protocols in low power and low data rate wireless sensor networks. In this paper, we develop a stochastic model for the beaconless operation of IEEE 802.15.4 MAC protocol. Given the number of nodes competing for channel access and their packet generation rates, the model predicts the packet loss probability and the packet latency. The model can also account for the impact of hidden nodes in certain situations. We compared the model predictions with NS2 simulation results and found an excellent match between the two for a wide range of the packet generation rates and the number of competing nodes in the network.

IEEE 802.11 and 802.16 Cooperation Within Multi-Radio Stations

In this paper we consider a multi-radio wireless network client that is capable of simultaneous operation in IEEE 802.16 and IEEE 802.11 telecommunication networks. In order to enable the cooperati...

Stable operation of IEEE 802.11e EDCA: Interaction between offered load and MAC parameters

In this paper, we study impacts of TXOP allocation and AIFS parameter on one hop IEEE 802.11e EDCA network under varying offered load. Offered load is modified by changing the parameters of arrival process and node populations. Arrival process is varied by altering burst size distribution, mean burst size, frame size, and arrival rates. We investigate the effects of the offered load parameters on the network stability and non-saturation boundaries of IEEE 802.11e EDCA. Our results show interaction of offered load and MAC parameters. The results suggest the range of network parameters which preserve network stability and still achieve QoS differentiation.

Paging and Location Management in IEEE 802.16j Multihop Relay Network

IEEE 802.16j is an emerging wireless broadband networking standard that integrates infrastructure base stations with multihop relay technology. Based on the idle mode operation in IEEE 802.16j, we propose a novel location management and paging scheme. It integrates the paging area-based and the timer-based location update mechanism. In paging area-based scheme, an idle mode mobile station updates when it moves to a new paging area. In timer-based scheme, an idle mode MS updates when the location update timer expires. In this work, we formulate the mathematical model to evaluate the performance of the proposed paging scheme. A new random walk mobility model that is suitable for modeling in multihop relay network is created. Optimization of location update timer is also investigated.

Channel assignment schemes for infrastructure-based 802.11 WLANs: A survey

Efficient channel assignment is crucial for successful deployment and operation of IEEE 802.11-based WLANs. In this article we present a survey on the state of the art channel assignment schemes in IEEE 802.11-based WLANs. After detailing out all the schemes, we provide a qualitative comparison among different schemes in terms of algorithm execution behaviors, complexity, and scalability. We then conclude the survey with several research issues open for further investigation.

Performance study and system optimization on sleep mode operation in IEEE 802.16e

Energy efficiency in mobile devices remains a critical issue in the design of wireless communication system. In order to provide a high quality of service (QoS), the IEEE 802.16e-2005 standard supports three unique power saving classes (PSCs) which aim to reduce the power consumption of mobile devices based on the different types of traffic. Our goal is to design an optimal sleep mode selection scheme so as to maximize the energy efficiency in a mobile WiMAX system while providing a certain QoS guarantee. In this paper, we propose a theoretical framework based on the semi-Markov decision process along with a performance evaluation on the sleep mode operation. Based on this model, we formulate a stochastic optimization problem and solve it through our novel policy optimization algorithm, which is capable of finding the optimal policy for the selection of different PSCs. The numerical and simulation results demonstrate the validity of our proposed scheme under different QoS requirements such as the packet delay and energy consumption level. We believe that our scheme has achieved a high energy efficiency and is best fit to the IEEE 802.16e mobile system.

The Effect of Terminal Movement on the Performance of IEEE 802.11 g Wireless LAN Systems in Simulated Radio Channels

The effect of terminal movement on the performance of the IEEE 802.11 g wireless LAN (WLAN) system is evaluated using a measurement set-up including a radio channel simulator. The evaluation is based on laboratory measurements of WLAN PC cards in different simulated radio environments. In the measurements, two different radio channel models are used; the exponential channel model and the UMTS vehicular channel model. The measurement results indicate promising operation of IEEE 802.11 g WLAN systems as such. However, the use of different packet sizes has a significant effect on the system behaviour. With large packets the terminal is more likely to experience channel estimation errors than with small packets. This is due to the fact that the IEEE 802.11 g receiver estimates the channel only once per frame, and uses this estimation over the entire frame. Based on the measurement results we suggest a modification to the medium access control (MAC) layer operation that overcomes this problem: the use of optimized fragmentation.