Saturation Throughput Performance Research Articles

Pseudorandom sequence contention algorithm for IEEE 802.11ah based internet of things network.

The IEEE 802.11ah standard relies on the conventional distributed coordination function (DCF) as a backoff selection method. The DCF is utilized in the contention-based period of the newly introduced medium access control (MAC) mechanism, namely restricted access window (RAW). Despite various advantages of RAW, DCF still utilizes the legacy binary exponential backoff (BEB) algorithm, which suffers from a crucial disadvantage of being prone to high probability of collisions with high number of contending stations. To mitigate this issue, this paper investigates the possibility of replacing the existing exponential sequence (i.e., as in BEB) with a better pseudorandom sequence of integers. In particular, a new backoff algorithm, namely Pseudorandom Sequence Contention Algorithm (PRSCA) is proposed to update the CW size and minimize the collision probability. In addition, the proposed PRSCA incorporates a different approach of CW freezing mechanism and backoff stage reset process. An analytical model is derived for the proposed PRSCA and presented through a discrete 2-D Markov chain model. Performance evaluation demonstrates the efficiency of the proposed PRSCA in reducing collision probability and improving saturation throughput, network throughput, and access delay performance.

A Distributed Ambient Backscatter MAC Protocol for Internet-of-Things Networks

Ambient backscatter communication enabling device-to-device (D2D) communications via the ambient radio frequency (RF) signal has revealed its numerous application potential in the Internet-of-Things (IoT) networks. However, the work on the link layer for the backscatter communication is in its infancy due to the constraints of ultralow power and cost in such a system, especially a channel access protocol in the backscatter communication system for IoT networks is rarely mentioned. In this article, a distributed multiple access control (MAC) protocol is presented, which allows multiple backscatter devices (BDs) to connect with each other by relying on the ambient RF signal. By combining an analog channel sensing strategy with the dual-backoff mechanism, each BD can switch among the transmission, receiving, and energy harvesting (EH) states. Specifically, each BD starts a randomly designated time for EH once the channel is sensed to be busy. As the timer expires, the BD ceases the EH and continues its sensing and backoff procedures. With the consideration of the false alarm and the miss detection problems occurring while sensing, an enhanced 3-D Markov model is built to analyze the saturation throughput performance of the proposed MAC protocol. Extensive simulations verify the analysis and demonstrate the advantage of the proposed backscatter MAC protocol.

Saturation Throughput and Delay Performance Evaluation of the IEEE 802.11g/n for a Wireless Lossy Channel

Saturation Throughput and Delay Performance Evaluation of the IEEE 802.11g/n for a Wireless Lossy Channel

Saturation Throughput and Delay Performance Evaluation of the IEEE 802.11g/n for a Wireless Lossy Channel

Non-ideal channel conditions degrade the performance of wireless networks due to the occurrence of frame errors. Most of the well-known works compute the saturation throughput and packet delay for the IEEE 802.11 Distributed Coordination Function (DCF) protocol with the assumption that transmission is carried out via an ideal channel (i.e., no channel bit errors or hidden stations), and/or the errors exist only in data packets. Besides, there are no considerations for transmission errors in the control frames (i.e., Request to Send (RTS), Clear to Send (CTS), and Acknowledgement (ACK)). Considering the transmission errors in the control frames adds complexity to the existing analysis for the wireless networks. In this paper, an analytical model to evaluate the Medium Access Control (MAC) layer saturation throughput and packet delay of the IEEE 802.11g and IEEE 802.11n protocols in the presence of both collisions and transmission errors in a non-ideal wireless channel is provided. The derived analytical expressions reveal that the saturation throughput and packet delay are affected by the network size (n), packet size, minimum backoff window size (Wmin), maximum backoff stage (m), and bit error rate (BER). These results are important for protocol optimization and network planning in wireless networks.

Saturation Throughput Analysis of an Asymmetric Full-Duplex MAC Protocol in WLANs With Hidden Terminals

The wireless in-band full-duplex technique enables wireless nodes to transmit and receive in the same channel simultaneously. To fully and effectively leverage this capability of the IBFD technique, new full-duplex medium access control (FD MAC) protocols that accommodate the features of the IBFD technique must be designed and analyzed. In this paper, we first propose an asymmetric FD MAC protocol, and then we develop an analytical model for the proposed protocol to evaluate the saturation throughput performance of wireless local area networks in the presence of hidden terminals. In the proposed protocol, asymmetric full-duplex transmissions can be established with the access point (AP) and two stations that hidden from each other. Thus, the well-known interstation interference problem in asymmetric full-duplex transmissions can be overcome. In the developed model, we adopt the stationary distribution of the backoff counter values at the beginning of a generic transmission to characterize the behavior of a node. The saturation throughput is then derived based on the stationary distribution. The accuracy of the proposed analytical model is verified through simulations. Using the proposed analytical model, the saturation throughput performance of the FD MAC protocols is studied with respect to different numbers of stations in each region and the minimum contention windows. In addition, the effects of hidden terminals on performance are thoroughly investigated, since the hidden terminals play an important role in the saturation throughput. Moreover, we compare the saturation throughput performance between symmetric and asymmetric FD MAC protocols to demonstrate the gains provided by asymmetric full-duplex transmissions.

A non-blocking wavelength routing ONoC based on two-dimension bus architecture

With the improvement of silicon-based optical devices and on-chip optical technologies, optical network-on-chip (ONoC) is becoming a significant interconnection solution for its high bandwidth, low network latency and efficient energy utilization. Some bus-based ONoCs face the problems of high bus congestion, low network utilization, which leads to high network latency and an extra overhead in power dissipation. In this paper, a non-blocking wavelength routing ONoC based on two-dimension bus architecture (2DWR-bus) is proposed to solve the problem face by previous bus-based ONoCs, realize multiple IP cores communicating with the same destination IP core simultaneously. The network simulation is carried out for the 16 cores and 64 cores ONoC under synthetic traffics. The end-to-end (ETE) delay and saturation throughput performance are evaluated and compared between 2DWR-bus and similarly-configured ONoCs. Netrace is used in the simulation to evaluate the network performance under realistic scientific application benchmarks. The insertion loss and required laser power for 2DWR-bus is calculated and made a comparison. The evaluation result shows that 2DWR-bus ONoC has better network performance when compared with other equivalent ONoCs, especially under high network offered load.

Saturation Throughput Analysis of IEEE 802.11 DCF with Heterogeneous Node Transmit Powers and Capture Effect

The transmit power control schemes allow the wireless nodes to select a minimum required transmit power from all available power levels to access the medium. In this paper, we focus on analysing the saturation throughput performance of IEEE 802.11 DCF networks with heterogeneous node transmit power levels and the capture effect. We first analyse the capture effect among packets sent at different power levels and derive the analytical expression of the capture probability. Then, we propose a three-dimensional Markov chain to model the backoff procedure performed by a tagged sending node under the condition of heterogeneous transmit power levels, and compute the total saturation throughput of the network with the previously derived capture probability. Finally, we validate the accuracy of our model by comparing the analytical results with the simulation results, and analyse the impact of the capture effect on the saturation throughput performance of IEEE 802.11 DCF networks.

Adaptive Multimode Medium Access Control for Underwater Acoustic Networks

Standards such as 802.11 have played a key role in the success of terrestrial radio wireless communications. Similar standardization will be needed in underwater acoustic networks (UANs) of the future. One of the important aspects of standardization is UAN medium access control (MAC). Since no single protocol can satisfy the diverse requirements of a general UAN MAC, we explore the possibility of combining multiple MAC protocols into a suite. We also consider physical-layer adaptation techniques as they are closely related to the MAC adaptation. The suite's key protocol mode called MACA-EA is a novel, enhanced adaptation of multiple access with collision avoidance (MACA) as used in 802.11. The suite uses two other modes-a centrally polled mode called MACA-C and a simple DATA-ACK protocol. Using both simulations and mathematical analysis, we compare saturated throughput performance and waiting time performance (in case of Poisson arrivals) of the different MAC protocol modes. We also benchmark the performance against ideal time-division multiple access (TDMA) performance. We present suitable adaptation techniques to switch between the protocol modes based on network requirements, traffic intensity, and quality-of-service QoS) requirements such as maximum allowed waiting time for reliable transfer. We propose an adaptation algorithm for automatically varying the batch size in MACA-C and MACA-EA for optimum performance. A key observation is that for ad hoc UANs, the adaptation of the multiple modes can lead to near-optimal performance across a wider range of traffic intensity, as compared to what any single protocol can achieve.

Performance Anomaly of the IEEE 802.11 DCF in Different Frame Error Rate Conditions

We propose an analytic model to compute the station's saturated throughput and packet delay performance of the IEEE 802.11 DCF (Distributed Coordination Function) in which frame transmission error rates in the channel are different from each other. Our analytic model shows that a station experiencing worse frame error rates than the others suffers severe performance degradation below its deserved throughput and delay performance. 802.11 DCF adopts an exponential back-off scheme. When some stations suffer from high frame error rates, their back-off stages should be increased so that others get the benefit from the smaller collision probabilities. This impact is then recursively applied to degrade the performance of the victim stations. In particular, we show that the performance is considerably degraded even if the frame error rate of the victim station satisfies the receiver input level sensitivity that has been specified in the IEEE 802.11 standard. We also verify the analytic results by the OPNET simulations.

Saturation Throughput Performance Analysis of a Medium Transparent MAC Protocol for 60 GHz Radio-Over-Fiber Networks

We demonstrate an analytical model for calculating the saturation throughput performance of a medium transparent medium access control (MAC) protocol in 60 GHz radio-over-fiber (RoF) networks. The proposed model incorporates effectively the medium transparent MAC mechanism, assuming a finite number of terminals and ideal channel conditions. It takes into account contention both at the optical and wireless layer, ensuring seamless and dynamic capacity allocation over both transmission media. This model enables extensive saturation throughput performance analysis for the medium transparent MAC and has been applied to 60 GHz RoF network scenarios considering variable numbers of available optical wavelengths, wireless nodes and serving antenna elements and for two different data rate values, namely 155 Mbps and 1 Gbps. Comparison between the model-based throughput results and respective simulation-based outcomes reveals that our model is extremely accurate in predicting the system throughput. Moreover, it confirms that the proposed medium transparent MAC protocol can effectively operate in high-speed 60 GHz RoF LAN environments.

Collaborative User Number Selection Based on Saturation Throughput and Sensing Performance

The number of collaborative users in a cognitive radio network is selected by maximizing the effective throughput of the cognitive radio network that considers both the spectrum-sensing performance and the saturation throughput performance. Numerical results show that the optimum number of collaborating users depends on the physical-layer techniques used, the physical channel conditions, and the upper-layer network parameters. These results give useful guidance on choosing the number of collaborative users involved in collaborative spectrum sensing.

Markov Model of DCF Protocol Based on Fixed Slot in Multi-Hop Ad Hoc Networks

指出了现有的基于不定长时隙的DCF协议马尔可夫链模型的局限性,并在详细分析多跳ad hoc 网络环境中DCF 协议建模的难点问题基础上,提出了一种基于定长时隙的多跳ad hoc 网络DCF 协议马尔可夫链模型.通过模型的求解,得到了反映多跳ad hoc 网络饱和吞吐量性能的相关性能指标的理论值,并结合GloMoSim 网络仿真环境中的仿真实验,证明了模型的有效性.;This paper points out the limitations of the existing Markov model of DCF protocol based on un-fixed slot in ad hoc networks, and analyzes the difficulty of the modeling of DCF protocol in multi-hop ad hoc networks in detail. On the basis of this, this paper proposes a Markov model of DCF protocol based on fixed slot in multi-hop ad hoc networks. By solving this model, the theoretic value which reflects the saturated throughput performance of multi-hop ad hoc networks is obtained. The effectiveness of this model is demonstrated by the simulations in GloMoSim environment.

Performance Analysis of IEEE 802.11 DCF in a Multi-Rate WLAN

The IEEE 802.11 family of specifications is by far the most prominent and successful technique for accessing WLANs. Because the channel used by wireless devices is a time-varying broadcast medium, these devices need to have multi-rate and rate-adaptive capability to adapt to the changing channel so that better performance can be achieved. In this paper, we propose an analytical model, which we call Rate-Adaptive Markov Chains, to study the saturation throughput and delay performance of an 802.11 WLAN in which the mobile hosts have multi-rate support, will use the ARF protocol to adapt rates for different channel qualities, and follow the DCF protocol to contend for data transmissions in a slowly-varying channel. Simulation results are also provided to verify the correctness of the model.

Short-term non-uniform access in IEEE 802.11-compliant WLANs: A study on its impact on the saturation performance

Along with the success of IEEE 802.11-compliant WLANs, the distributed coordinated function (DCF) specified as the contention-based medium access mechanism in IEEE 802.11 has been widely used to support applications in new regimes. A thorough understanding of the characteristics of IEEE 802.11 DCF is therefore a research focus. DCF assumes the binary exponential backoff algorithm (BEBA) [D. Bertsekas, R. Gallager, Data Networks, Prentice Hall, 1992]. Several existing models that characterize BEBA as a p-persistent scheme have ignored several subtle protocol details. This has practically constrained the models from being applied in a broader range of configurations, e.g., small contention window, and from being further extended, e.g., 802.11e EDCA. In this paper, we develop an analytical model that captures the subtlety, and faithfully describes the channel activities as governed by DCF. Based on the devised model, we perform a rigorous analysis on the saturation throughput performance in a single-hop WLAN. We show that the stochastic property of the backoff time, r, may substantially impact the system performance. For example, setting the range of r to [1,CW] instead of [0,CW-1], can degrade the system throughput considerably. We also identify, by clearly defining and thus being able to differentiate the two terms, attempt probability and transmission probability, an erroneous extension made to Bianchi's model [G. Bianchi, Performance analysis of the IEEE 802.11 distributed coordination function, IEEE JSAC, 18(3) (2000) 535-547]. All the findings are corroborated by ns-2 simulation.

A new call admission control method for providing desired throughput and delay performance in IEEE802.11e wireless LANs

The draft IEEE 802.11e standard aims at providing quality of service (QoS) support in 802.11 wireless local area networks (WLANs). Enhanced distributed coordination function (EDCF), being the fundamental medium access control mechanism in IEEE 802.11e, can only provide service differentiation but offers no QoS guarantees. While service differentiation does not perform well under high traffic load conditions, call admission control (CAC) becomes necessary in order to provide and support the QoS of existing calls. In this paper, we first analyze the saturation throughput and mean access delay performance of differentiated service provided by EDCF. Specifically, we investigate the impact of transmission opportunity (TXOP) and wireless channel errors on the performance of the EDCF. Based on the results from this analysis, we propose a new CAC algorithm that provides the desired throughput and access delay performance. Simulated performance results demonstrate the effectiveness of the proposed CAC algorithm

Performance of an Aggregation-Based MAC Protocol for High-Data-Rate Ultrawideband Ad Hoc Networks

Ultrawideband (UWB) communication is an emerging technology that promises to provide high data rate communication for wireless personal area networks. One of the critical challenges in UWB system design is the timing acquisition problem, i.e., a receiver needs a relative long time to synchronize with transmitted signals. Clearly, the timing acquisition overhead will significantly limit the throughput of high data rate UWB ad hoc networks. To resolve the timing acquisition problem, the authors proposed a general framework for medium access control (MAC) protocols in their previous work (K. Lu, D. Wu, and Y. Fang, "A novel framework for medium access control in ultra-wideband ad hoc networks," Dynamics of Continuous, Discrete and Impulsive Systems (Series B), vol. 12, no. 3, pp. 427-441, Jun. 2005); under the framework, a transmitting node can aggregate multiple upper layer packets into a burst frame at the MAC layer. In this paper, the authors propose an aggregation-based MAC protocol within the framework. Besides packet aggregation, they also design a novel retransmission scheme which is suitable for error-prone wireless environment, in which only the packets that encounter transmission errors will be retransmitted. To evaluate the performance of the protocol, they develop a three-dimensional Markov chain model for the saturated throughput performance. In addition, they also analyze the end-to-end delay performance through simulation. Extensive numerical and simulation results show that, compared to existing MAC protocols, in which upper layer packets are transmitted one by one, the proposed protocol can drastically reduce the timing acquisition overhead. Consequently, both the throughput and the end-to-end delay performance can be significantly improved

Saturation throughput analysis of error‐prone 802.11 wireless networks

AbstractIt is well known that the medium access control (MAC) layer is the main bottleneck for the IEEE 802.11 wireless LANs. Much work has been done on performance analysis of the 802.11 MAC. However, most of them assume that the wireless channel is error free. In this paper, we investigate the saturation throughput performance achieved at the MAC layer, in both congested and error‐prone channels. We provide a simple and accurate analytical model to calculate the MAC throughput. The model is validated through extensive simulation results. Our results show that channel errors have a significant impact on the system performance. Copyright © 2005 John Wiley & Sons, Ltd.

A Unified Model for the Performance Analysis of IEEE 802.11e EDCA

Rapid deployment of IEEE 802.11 wireless local area networks (WLANs) and their increasing quality of service (QoS) requirements motivate extensive performance evaluations of the upcoming 802.11e QoS-aware enhanced distributed coordination function (EDCA). Most of the analytical studies up-to-date have been based on one of the three major performance models in legacy distributed coordination function analysis, requiring a large degree of complexity in solving multidimensional Markov chains. Here, we expose the common guiding principle behind these three seemingly different models. Subsequently, by abstracting, unifying, and extending this common principle, we propose a new unified performance model and analysis method to study the saturation throughput and delay performance of EDCA, under the assumption of a finite number of stations and ideal channel conditions in a single-hop WLAN. This unified model combines the strengths of all three models, and thus, is easy to understand and apply; on the other hand, it helps increase the understanding of the existing performance analysis. Despite its appealing simplicity, our unified model and analysis are validated very well by simulation results. Ultimately, by means of the proposed model, we are able to precisely evaluate the differentiation effects of EDCA parameters on WLAN performance in very broad settings, a feature which is essential for network design.

Saturation Throughput Analysis of Collision Management Protocol in the HomePNA 3.0 Asynchronous MAC Mode

The Home Phoneline Networking Alliance (HomePNA) 3.0 technology is designed to provide high-speed backbones for home multimedia networks. This technology adopts a collision management protocol in an asynchronous medium access control (MAC) mode to reduce the number of collisions. In this letter, we present a simple analytical model to compute the saturation throughput performance of the collision management protocol, and compare the performance with that of HomePNA 2.0.

Performance Model of IEEE 802.11 DCF With Variable Packet Length

Few analytical models have been proposed to evaluate the hybrid of the basic and the RTS/CTS access mechanisms up to now. The main reason is that it is very difficult to study a scheme with variable packet length. In this letter, we propose a model to evaluate the saturation throughput performance of the hybrid access mechanism, assuming that the packet lengths are sampled from a general distribution function f(x).