Showing papers on "Frame aggregation published in 2017"
TL;DR: Impact of HT-WLAN PHY and MAC layer enhancements on various transport and application layer protocols is discussed and several research works that use aforesaid enhancements effectively to boost up data rate of end-to-end protocols are summarized.
Abstract: Since the inception of IEEE 802.11 wireless local area networks (WLANs) in 1997, wireless networking technologies have tremendously grown in the last few decades. The fundamental IEEE 802.11 physical (PHY) and medium access control (MAC) protocols have continuously been enriched with new technologies to provide the last mile wireless broadband connectivity to end users. Consequently, several new amendments of the basic IEEE 802.11 gradually came up in the forms of IEEE 802.11a, IEEE 802.11b, and IEEE 802.11g. More recently, IEEE 802.11n, IEEE 802.11ac, and IEEE 802.11ad are introduced with enhanced PHY and MAC layers that boost up physical data rates to the order of Gigabit per second. So, these amendments are generally known as high throughput WLANs (HT-WLANs). In HT-WLANs, PHY layer is enhanced with multiple-input multiple-output antenna technologies, channel bonding, short guard intervals, enhanced modulation and coding schemes. The MAC sublayer overhead is reduced by introducing frame aggregation and block acknowledgement technologies. However, several existing studies reveal that, many a time, the aforesaid PHY and MAC enhancements yield negative impact on various upper layer protocols, that is end-to-end transport and application layer protocols. As a consequence, a large number of researchers have focused on improving the coordination among PHY/MAC and upper layer protocols. In this survey, we discuss impact of HT-WLAN PHY and MAC layer enhancements on various transport and application layer protocols. This paper also summarizes several research works that use aforesaid enhancements effectively to boost up data rate of end-to-end protocols. We also point out limitations of the existing researches and list down different open challenges that can be meaningfully explored for the development of the next generation HT-WLAN technologies.
93 citations
07 Aug 2017
TL;DR: This paper introduces new buffer management algorithms that allow participating APs to manage eachOthers' queues, rapidly quenching each others' transmissions and flushing each others', making the system effective at modern 802.11 bit rates that need frame aggregation to maintain high spectral efficiency.
Abstract: This paper presents the design and implementation of Wi-Fi Goes to Town, the first Wi-Fi based roadside hotspot network designed to operate at vehicular speeds with meter-sized picocells. Wi-Fi Goes to Town APs make delivery decisions to the vehicular clients they serve at millisecond-level granularities, exploiting path diversity in roadside networks. In order to accomplish this, we introduce new buffer management algorithms that allow participating APs to manage each others' queues, rapidly quenching each others' transmissions and flushing each others' queues. We furthermore integrate our fine-grained AP selection and queue management into 802.11's frame aggregation and block acknowledgement functions, making the system effective at modern 802.11 bit rates that need frame aggregation to maintain high spectral efficiency. We have implemented our system in an eight-AP network alongside a nearby road, and evaluate its performance with mobile clients moving at up to 35 mph. Depending on the clients' speed, Wi-Fi Goes to Town achieves a 2.4-4.7x TCP throughput improvement over a baseline fast handover protocol that captures the state of the art in Wi-Fi roaming, including the recent IEEE 802.11k and 802.11r standards.
32 citations
01 May 2017
TL;DR: STRALE, a standard-compliant and mobility-aware PHY rate and A-MPDU length adaptation scheme with ease of implementation, is developed and demonstrated that STRALE achieves up to 2.9x higher throughput, compared to a fixed duration setting according to IEEE 802.11 standard.
Abstract: IEEE 802.11n/ac wireless local area network (WLAN) supports frame aggregation, called aggregate medium access control (MAC) protocol data unit (A-MPDU), to enhance MAC efficiency by reducing protocol overhead. However, the current channel estimation process conducted only once during the preamble reception is known to be insufficient to ensure robust delivery of long A-MPDU frames in mobile environments. To cope with this problem, we first build a model which represents the impact of mobility with a noise vector in the I-Q plane, and then analyze how the mobility affects the A-MPDU reception performance. Based on our analysis, we develop STRALE, a standard-compliant and mobility-aware PHY rate and A-MPDU length adaptation scheme with ease of implementation. Through extensive simulations with 802.11ac using ns-3 and prototype implementation with commercial 802.11n devices, we demonstrate that STRALE achieves up to 2.9x higher throughput, compared to a fixed duration setting according to IEEE 802.11 standard.
32 citations
01 Feb 2017
TL;DR: In this article, a new dynamic frame aggregation (DFA) scheduler is proposed to provide QoS satisfaction to real-time services over IEEE 802.11n, where new scheduling parameters such as QoS delays are defined to avoid accumulation of non-scheduled packets.
Abstract: Providing Quality of Service (QoS) to real time applications over Wireless Local Area Networks (WLANs) is becoming a very challenging task due to the diversity of multimedia applications. Concurrently, there are numerous WLANs devices that are rising recently. Mainly, we focus on IEEE 802.11n since it was designed to support a high data transmission rate (toward 600 Mbps) based on frame aggregation schemes. The aggregation mechanism accumulates many frames before transmitting them into a single larger frame, thus reducing overhead and increasing efficiency and throughput. Yet, this scheme cannot provide QoS satisfaction for delay sensitive application even if it supports higher throughputs. Indeed, aggregation headers cause supplementary delays particularly when aggregating unfrequent packets with small sizes. To overcome this limitation, we propose in this paper a new Dynamic Frame Aggregation (DFA) scheduler to provide QoS satisfaction to real time services. To achieve this goal, we defined new scheduling parameters such as QoS delays to avoid accumulation of non-scheduled packets. Hence, the DFA scheduler serves packets and dynamically adjusts the aggregated frame size based on these QoS delays. Conducted simulations illustrate the performance of our proposed DFA scheduler in term of satisfying QoS, throughput, loss and delay requirements of voice and video traffics.
31 citations
TL;DR: An adaptive frame length aggregation scheme (AFLAS) for VANETs is proposed, which is designed to improve transmission efficiency and increase data throughput and exhibits significant improvement results in data throughput, retransmissions, overheads, and transmission efficiency in comparison with nonadaptive aggregation schemes.
Abstract: Vehicular ad hoc networks (VANETs) experience large-scale high-speed mobility and volatile topology. VANETs may therefore experience intermittent connections and may occasionally be unable to guarantee end-to-end connections. This gives the medium access control (MAC) layer the opportunity to adapt its transmission strategy to the current unstable wireless connections to improve transmission efficiency. In this paper, we propose an adaptive frame length aggregation scheme (AFLAS) for VANETs, which is designed to improve transmission efficiency and increase data throughput. In our scheme, the incoming data packets from higher layers are queued separately in the MAC layer to wait for transmission opportunities. Suitable aggregation frame lengths are calculated according to the current wireless status and applied in the MAC layer at the onset of data transmissions. In this paper, we analyze and apply our AFLAS strategy to two current frame aggregation schemes in IEEE 802.11. We also report on the performance evaluation of our scheme. Our results exhibit significant improvement results in data throughput, retransmissions, overheads, and transmission efficiency in comparison with nonadaptive aggregation schemes.
29 citations
TL;DR: A frame aggregation scheme by using the aggregated-MAC protocol data unit (A-MPDU) which works with the IEEE 802.15.4 MAC layer is proposed which provides the optimal performance considering the required QoS.
Abstract: In wireless body area sensor networks (WBASNs), Quality of Service (QoS) provision for patient monitoring systems in terms of time-critical deadlines, high throughput and energy efficiency is a challenging task. The periodic data from these systems generates a large number of small packets in a short time period which needs an efficient channel access mechanism. The IEEE 802.15.4 standard is recommended for low power devices and widely used for many wireless sensor networks applications. It provides a hybrid channel access mechanism at the Media Access Control (MAC) layer which plays a key role in overall successful transmission in WBASNs. There are many WBASN’s MAC protocols that use this hybrid channel access mechanism in variety of sensor applications. However, these protocols are less efficient for patient monitoring systems where life critical data requires limited delay, high throughput and energy efficient communication simultaneously. To address these issues, this paper proposes a frame aggregation scheme by using the aggregated-MAC protocol data unit (A-MPDU) which works with the IEEE 802.15.4 MAC layer. To implement the scheme accurately, we develop a traffic patterns analysis mechanism to understand the requirements of the sensor nodes in patient monitoring systems, then model the channel access to find the performance gap on the basis of obtained requirements, finally propose the design based on the needs of patient monitoring systems. The mechanism is initially verified using numerical modelling and then simulation is conducted using NS2.29, Castalia 3.2 and OMNeT++. The proposed scheme provides the optimal performance considering the required QoS.
22 citations
TL;DR: The results show that aggregation parameters can be tuned in order to keep latency in low levels, with a low throughput penalty.
Abstract: Frame aggregation is widely used in 802.11 WLANs in order to provide a significant throughput improvement. However, the latency increase that comes as a counterpart can reduce the quality experienced by the users of applications with real-time constraints. This letter explores the throughput versus latency tradeoff in the context of central controlled solutions (e.g. SDWN-based). First, a scenario with a single Access Point (AP) is used to illustrate the problem and to propose two possible solutions. Then, a centralized algorithm that dynamically (de)activates aggregation is tested in a scenario with a number of APs. The results show that aggregation parameters can be tuned in order to keep latency in low levels, with a low throughput penalty.
20 citations
Posted Content•
TL;DR: The impact of enhancements of PHY/MAC layer in HT-WLANs over transport/application layer protocols is discussed and different open challenges that can be explored for the development of next generation HT- WLAN technologies are list down.
Abstract: Since the inception of Wireless Local Area Networks (WLANs) in the year 1997, it has tremendously grown in the last few years. IEEE 802.11 is popularly known as WLAN. To provide the last mile wireless broadband connectivity to users, IEEE 802.11 is enriched with IEEE 802.11a, IEEE 802.11b and IEEE 802.11g. More recently, IEEE 802.11n, IEEE 802.11ac and IEEE 802.11ad are introduced with enhancements to the physical (PHY) layer and medium access control (MAC) sublayer to provide much higher data rates and thus these amendments are called High Throughput WLANs (HT-WLANs). For both standards, PHY is enhanced with multiple-input multiple-output (MIMO) antenna technologies, channel bonding, short guard intervals (SGI), enhanced modulation and coding schemes (MCS). At the same time, MAC layer overhead is reduced by introducing frame aggregation and block acknowledgement technologies. However, existing studies reveal that although PHY and MAC enhancements promise to improve physical data rate significantly, they yield negative impact over upper layer protocols -- mainly for reliable end-to-end transport/application layer protocols. As a consequence, a large number of schools have focused researches on HT-WLANs to improve the coordination among PHY/MAC and upper layer protocols and thus, boost up the performance benefit. In this survey, we discuss the impact of enhancements of PHY/MAC layer in HT-WLANs over transport/application layer protocols. list down different open challenges that can be explored for the development of next generation HT-WLAN technologies.
19 citations
TL;DR: An adaptive automated on-line learning mechanism, called “Smart Link Adaptation” (SmartLA), for dynamic selection of link parameters, motivated by “State-Action-Reward- state-Action (SARSA) model) model, a variant of reinforcement learning is designed.
17 citations
12 Jun 2017
TL;DR: It is shown not only how frame aggregation breaks existing lightweight mechanisms for link characterization but also how to carefully construct packet sequences that induce frame aggregation to capture the WiFi available bandwidth.
Abstract: WiFi has emerged as a pivotal technology for mobile devices offering the potential for exceptional connectivity speeds. Unfortunately, the performance of WiFi may vary significantly making WiFi link characterization (and more broadly the path characterization) an essential element of the user Quality of Experience (QoE). The key challenge that emerges with respect to link characterization is how to characterize performance in an efficient manner. In this paper, we explore how the existing frame aggregation mechanisms introduced by 802.11e can be leveraged to achieve such a goal. We show not only how frame aggregation breaks existing lightweight mechanisms for link characterization but also how to carefully construct packet sequences that induce frame aggregation to capture the WiFi available bandwidth. We construct a proof of concept system, AIWC (Aggregation Intensity based Wifi Characterization), to demonstrate the aforementioned concepts with significant improvements versus prior work.
16 citations
21 May 2017
TL;DR: It is shown that the spectrum utilization increases when it is divided into multiple narrow channels instead of fewer wide channels, and this increase is very significant when the frame aggregation is disabled.
Abstract: IEEE 802.11ac is a recent amendment that enhances the throughput of WLANs. It uses spatial diversity, new modulation and coding schemes (MCS), and channel bonding to increase the data rate. The channel bonding allows 802.11ac stations, also called Very High Throughput (VHT) stations, to operate on channels wider than the legacy 20 MHz channel in the 5 GHz band. Particularly, a VHT station may support up to 160 MHz transmissions. Increasing the channel width enhances the data rate but reduces the number of non-overlapping channels. For example, the 5 GHz spectrum in Europe offers either 19 nonoverlapping 20 MHz channels or only two 160 MHz channels. In dense WLAN deployment environments, the use of channel bonding increases the number of networks and stations sharing the same medium, and may increase the collisions rate. In this paper we show that the spectrum utilization increases when it is divided into multiple narrow channels instead of fewer wide channels. This increase is very significant when the frame aggregation is disabled. We show that 8 × 20 MHz channels may offer 252 Mbps compared to only 51 Mbps in a 160 MHz channel.
01 Feb 2017
TL;DR: This paper implemented an aggregation scheme by combining these two types of mechanism an analyzed its performance by using NS-3 in multi-client mode and found the simulation result outperformed in case of throughput.
Abstract: IEEE 802.11 based Wireless Local Area Networks (WLANs) are widely used because of its flexibility. IEEE 802.11n is the latest inclusion in IEEE 802.11 standard. High throughput can be gained by enhancing the performance medium access control (MAC) layer. In that case MAC layer Frame Aggregation Mechanism can be used. Two types of frame aggregation are introduced by this standard namely MAC Service Data Unit (MSDU) aggregation and MAC Proto-col Data Unit (MPDU) aggregation. In this paper we have implemented an aggregation scheme by combining these two types of mechanism an analyzed its performance by using NS-3 in multi-client mode. The simulation result outperformed in case of throughput.
01 Oct 2017
TL;DR: This paper proposes an adaptive learning mechanism, HT-MobiRate, for high throughput dynamic link adaptation under mobile scenario and recognizes that it performs considerably better than other competing schemes proposed in the literature for link adaptation in static environment.
Abstract: High fluctuation of signal strength is evident in wireless channel under mobile environment. IEEE 802.11n and IEEE 802.11ac based wireless technologies experience a challenge for selecting link configuration parameters, like number of spatial streams, channel bonding, advanced modulation and coding schemes, frame aggregation etc., dynamically under mobility. Selection of the best possible data rate by tuning link parameters is a challenging issue due to the channel asymmetry in mobile environment. In this paper, we propose an adaptive learning mechanism, HT-MobiRate, for high throughput dynamic link adaptation under mobile scenario. HT-MobiRate is based on Thompson sampling and inspired from multi-armed bandit approach. To the best of our knowledge, this invention is first in the direction of link adaptation for IEEE 802.11ac under mobile environment. We analyze the performance of HT-MobiRate with a practical high throughput wireless testbed built over 6 IEEE 802.11ac supported access points and 20 IEEE 802.11ac clients (both client boards as well as smart-phones). We recognize that it performs considerably better than other competing schemes proposed in the literature for link adaptation in static environment.
01 Mar 2017
TL;DR: These techniques are described as well as an analytical relationship between saturation throughput of the network and other network parameters such as-Aggregation Size, Signal to Noise Ratio (SNR) etc are established.
Abstract: IEEE 802.11n and IEEE 802.11ac are called next generation Wireless LANs (WLANs) for their revolutionary improvement in performance. Two key techniques that enhance the performances of these standards are frame aggregation and Block Acknowledgement (BLOCK ACK). In this paper, we describe these techniques as well as establish an analytical relationship between saturation throughput of the network and other network parameters such as-Aggregation Size, Signal to Noise Ratio (SNR) etc. We validate our analysis using network simulator-3 (ns-3) simulations. Additionally, we examine the performance of frame aggregation and Block ACK mechanism using the same. The analysis and simulation led us to enlist some open issues regarding frame aggregation in the concluding section.
TL;DR: This paper discusses the main PHY and MAC layer amendments proposed for IEEE 802.11ah, and investigates the operability of the aforementioned standard as a backhaul link to connect devices over a long range.
Abstract: The most essential part of Internet of Things (IoT) infrastructure is the wireless communication system that acts as a bridge for the delivery of data and control messages. However, the existing wireless technologies lack the ability to support a huge amount of data exchange from many battery driven devices spread over a wide area. In order to support the IoT paradigm, the IEEE 802.11 standard committee is in process of introducing a new standard, called IEEE 802.11ah. This is one of the most promising and appealing standards, which aims to bridge the gap between traditional mobile networks and the demands of the IoT. In this paper, we first discuss the main PHY and MAC layer amendments proposed for IEEE 802.11ah. Furthermore, we investigate the operability of IEEE 802.11ah as a backhaul link to connect devices over a long range. Additionally, we compare the aforementioned standard with previous notable IEEE 802.11 amendments (i.e. IEEE 802.11n and IEEE 802.11ac) in terms of throughput (with and without frame aggregation) by utilizing the most robust modulation schemes. The results show an improved performance of IEEE 802.11ah (in terms of power received at long range while experiencing different packet error rates) as compared to previous IEEE 802.11 standards.
01 Jan 2017
TL;DR: This paper proposes a fronthaul frame aggregation strategy to improve the packet transmission efficiency while keeping the average fr onthaul queueing delay and jitter constant regardless of the percentage of fronnthaul traffic.
Abstract: Virtualization of the base station for the purpose of centralization is being actively studied and researched as an implementation option for 5G mobile networks. Proposed as Cloud radio access network, the technology is expected to facilitate easier operation and maintenance than regular radio access networks. However, the base stations traffic has stringent delay requirements. In this paper, we explore the possibility of multiplexing fronthaul traffic and traditional backhaul traffic as it traverses over the metropolitan network while keeping the average fronthaul queueing delay and jitter under control. We analyze and simulate the cases of a single fronthaul flow and multiple fronthaul flows arriving at the packet switch assuming strict priority for the fronthaul queue. We propose a fronthaul frame aggregation strategy to improve the packet transmission efficiency while keeping the average fronthaul queueing delay and jitter constant regardless of the percentage of fronthaul traffic. While the criteria for aggregation is different for the 2 cases, we show that the optimal number of basic frames to aggregate is between 3-10 frames assuming the Common Public Radio Interface protocol.
01 Jan 2017
TL;DR: This paper proposes a new method to determine the frame aggregation size considering both channel utilization and delay data frames suffer from in transmission queues, and shows that this method provides high channel efficiency with keeping transmission delay in a relatively small value.
Abstract: In order to improve the throughput over WLAN, the IEEE 802.11ac standard, which has been used recently, introduces the frame aggregation and MU-MIMO (multi-user multiple-input and multiple-output) mechanisms. The frame aggregation concatenates multiple data frames in one MAC data unit. MU-MIMO provides SDMA (space division multiple access), which allows multiple STAs (stations) to share space resources. In an 802.11ac WLAN, MU-MIMO is used in the downlink data transfer in a way that data frames to multiple STAs are aggregated separately and transmitted at the same time. When traffic loads to individual STAs are different, however, it is possible that there is a waste in space and time resources. In order to avoid this waste, several methods to control the frame aggregation size for MU-MIMO are proposed. Those methods focus mainly on increasing the channel utilization, and so they have a problem that there is a large delay in transmitting an aggregated data unit. In this paper, we propose a new method to determine the frame aggregation size considering both channel utilization and delay data frames suffer from in transmission queues. A performance evaluation result shows that our method provides high channel efficiency with keeping transmission delay in a relatively small value.
01 Mar 2017
TL;DR: An analytical model is described to compute the maximum achievable throughput with two level MAC frame aggregation for various physical layer modulation and coding schemes and results show that frame aggregation is mandatory for 802.11ad WLAN systems.
Abstract: IEEE 802.11ad standard defines high data rate WLAN at 60 GHz. It uses a hybrid MAC protocol consists of CSMA/CA and TDMA. This paper investigates theoretical maximum throughput of IEEE 802.11ad milli meter Wave (mmWave) WLAN during contention based access period (CBAP). We describe an analytical model to compute the maximum achievable throughput with two level MAC frame aggregation for various physical layer modulation and coding schemes. ns-3 simulations are used for validating the result. MAC frame size which maximizes the throughput under error prone channels is also calculated. Numerical and simulation results show that frame aggregation is mandatory for 802.11ad WLAN systems.
Patent•
05 Oct 2017
TL;DR: In this paper, a method for configuring an aggregated frame for efficient wireless communication in a high density environment, and a wireless communication method using the same, is presented, the method comprising the steps of: generating aggregated MPDU (A-MPDU) containing a plurality of MAC protocol data unit (MPDUs) groups to which independent modulation and coding schemes are individually applied.
Abstract: The present invention relates to a method for configuring an aggregated frame for efficient wireless communication in a high density environment, and a wireless communication method using the same. To this end, the present invention provides a wireless communication method by a terminal and a wireless communication terminal using the same, the method comprising the steps of: generating an aggregated MPDU (A-MPDU) containing a plurality of MAC protocol data unit (MPDU) groups to which independent modulation and coding schemes are individually applied; and transmitting the generated A-MPDU.
Patent•
10 May 2017
TL;DR: In this article, the authors proposed a time period reduction-based fair access method for Terahertz wireless personal area networks (TPA) which can be used for mainly solving problems that a random access time period becomes redundant when a time slot request quantity is greater than the time slot quantity provided by two super frames.
Abstract: The invention belongs to the field of Terahertz wireless personal area networks and specifically relates to a time period reduction-based fair access method. The time period reduction-based fair access method can be used for mainly solving problems that a random access time period becomes redundant when a time slot request quantity is greater than a time slot quantity provided by two super frames via a relevant access method, that distributable time slots can hardly be completely distributed via a conventional fair access method, and that subsequent subframes are retransmitted unnecessarily via a conventional low time delay frame aggregation mechanism when length information of a subframe head is damaged; the method comprises operation of the following three time periods: beacon broadcast, data transmission and random access; in the beacon broadcast time period, the random access time period can be cancelled in a self-adaptive manner according to the size of the time slot request quantity, and time slots can be distributed to nodes in an ordered and fair way according to the size of the request quantity; in the data transmission time period, a frame aggregation mode is used for subjecting a subframe with maximum length to reverse aggregation operation, and therefore time slot utilization rates, network throughputs and data time delay performance can be improved while normal access to a Terahertz wireless personal area network can remain unaffected and node access fairness can be enuserd.
10 Jul 2017
TL;DR: A software-defined networking framework for link adaptation in mobile environment, that engages an adaptive learning-based methodology, ϵ--greedy policy, and observes that this approach provides a significant better performance compared to other competing schemes proposed in the literature.
Abstract: High throughput wireless access networks such as IEEE 802.11ac show a significant challenge in choosing link configuration parameters dynamically based on channel condition. It is due to a large pool of design set like channel bonding, number of spatial streams, guard intervals, different modulation and coding schemes, frame aggregation etc. Selection of such parameters is far challenging in mobile environment where signal strength fluctuates frequently. In this paper, we design a software-defined networking (SDN) framework for link adaptation in mobile environment, that engages an adaptive learning-based methodology, ϵ--greedy policy. The proposed link adaptation mechanism, Linkcon, explores several possible configuration options on the basis of their impact on network performance in various channel conditions. We analyze the performance of Linkcon from simulation results. We observe that this approach provides a significant better performance compared to other competing schemes proposed in the literature.
01 Jun 2017
TL;DR: It is proved that voice streams particularity in terms of bandwidth, pattern and packet format has its own fallouts on the aggregation scheme, and a frame aggregation scheme for VoIP traffic over wireless local area network is proposed.
Abstract: This paper proposes a frame aggregation scheme for VoIP traffic over wireless local area network. In this context, we studied main attributes of VoIP in wireless systems, and recalled its basic requirements when it comes to quality of service. We proved that voice streams particularity in terms of bandwidth, pattern and packet format has its own fallouts on the aggregation scheme. This involves basically the aggregation method, the aggregate exchange and the frame sizing. A well fitted aggregation implies a limited aggregate size range to append tolerable delays to higher efficiency. A performance analysis illustrated better response in terms of delay, delay variation and spectral efficiency compared to a legacy non-aggregate scheme.
01 May 2017
TL;DR: It is posited that the recent introduction of frame aggregation by 802.11e can offer a compact and efficient representation of expected throughput for improving AP selection and it is shown that by conveying the characteristics of subframes during frame aggregation, it can uniquely embody the utilization, interference, and backlog traffic pressure for an access point.
Abstract: With the incredible rise in WiFi devices, proper assessment for performance is essential for Quality of Experience (QoE). In the past, many access point (AP) assessment metrics have been exploited to achieve optimal AP selection. However, these conventional metrics (e.g., throughput) are insufficient to capture the full dynamics of the AP load condition. In our paper, we posit that the recent introduction of frame aggregation by 802.11e can offer a compact and efficient representation of expected throughput for improving AP selection. We show that by conveying the characteristics of subframes during frame aggregation, we can uniquely embody the utilization, interference, and backlog traffic pressure for an access point. We validate the effectiveness of the proposed metrics with the commercial off the shelf (COTS) experiments. In addition, we explore an application case of using the metrics by adopting simple machine learning methods.
TL;DR: It is proved that a carefully chosen set of parameters can increase the throughput remarkably with the hybrid aggregation scheme A-MPDU of A-MSDU providing the best results for the chosen scenario.
Abstract: In this paper, we present the Very High Throughput (VHT) introduced for the first time by the standard IEEE 802.11ac. We show that we can find an optimized set of parameters which leads to the best performance. We analyze the performance of the standard, while taking into account several features of the PHY and the MAC layers in a MIMO channel, and we compute the throughput using an analytical model verified by simulation of the performance of different aggregation schemes, different modulation and coding schemes and various channel widths. We prove that a carefully chosen set of parameters can increase the throughput remarkably with the hybrid aggregation scheme A-MPDU of A-MSDU providing the best results for the chosen scenario.
Patent•
31 May 2017
TL;DR: In this article, an MAC layer queue scheduling method of a TDMA ad hoc network for mainly solving the problems of poor fairness, too long delay and waste of system resources in the prior art is presented.
Abstract: The invention discloses an MAC layer queue scheduling method of a TDMA ad hoc network for mainly solving the problems of poor fairness, too long delay and waste of system resources in the prior art. The scheme is as follows: selecting a business time slot of a present node, and performing queue scheduling: 1, judging whether a data frame with a waiting time exceeding a waiting threshold, judging whether a queue with a queue length exceeding a queue length critical value, if both of the two situations do not exist, counting the number of neighbor nodes having the maximum transmission unit value; 2, comparing queue priority and queue length in N neighbor nodes, and selecting a neighbor node to serve as destination neighbor node; and 3, determining the number of the sent data frames according to the maximum transmission unit value of the destination neighbor node, and sending the data frames in a frame aggregation manner. The MAC layer queue scheduling method disclosed by the invention has the advantages of high fairness, low delay, timely data processing and large throughput, and can be used for providing a scheduling mode with delay and throughput guarantee for MAC layer data transmission.
01 Oct 2017
TL;DR: Simulation and numerical results show the proposed scheme significantly improves the data throughput and the channel utilization, and decreases overheads and retransmissions in comparison to the fixed frame aggregation scheme.
Abstract: Due to the volatile network topology and time-varying channel conditions, high-efficient data transmission in Vehicular Ad-hoc Networks (VANETs), especially for error-prone channels, is a challenging task. In the paper, we investigate traffic scheduling based on the Remaining Delay (RD) and propose an adaptive frame length aggregation stategy with the RD limit in VANETs. In our scheme, we classify the incoming packets from upper layer into three priority queues according to the maximum tolerable delay of the traffic flows, and the traffic flows which have the lowest RD are given the higher priority to be transmitted. Also, an theoretical analysis which reveals the relationship between the saturated throughput and Bit Error Rate (BER) is obtained to calculate an optimal aggregated frame length under the RD limit for MAC Service Data Unit Aggregation (A-MSDU) scheme. Simulation and numerical results show the proposed scheme significantly improves the data throughput and the channel utilization, and decreases overheads and retransmissions in comparison to the fixed frame aggregation scheme.
TL;DR: Simulation results validate the efficiency of the suggested MAC aggregation mechanism and aggregation sizes are adapted to achieve throughput optimization and shows significant improvement between measurement defined by the draft of IEEE802.11n and the proposed methodology.
Abstract: One of the promising candidate access technology for wireless communication in present and the future scenario is based on IEEE 802.11 Wireless LAN (WLAN) standard. The popularity of WLAN is furthe...
Posted Content•
TL;DR: Evaluations on a model show that instead of implementing a complex adaptive AM SDU frame aggregation mechanism which impact queuing and other implementation aspects, it is easier to influence packet error rate with traditional mechanisms while keeping the AMSDU aggregation logic simple.
Abstract: Frame aggregation is a mechanism by which multiple frames are combined into a single transmission unit over the air. Frames aggregated at the AMSDU level use a common CRC check to enforce integrity. For longer aggregated AMSDU frames, the packet error rate increases significantly for the same bit error rate. Hence, multiple studies have proposed doing AMSDU aggregation adaptively based on the error rate. This study evaluates if there is a \emph{practical} advantage in doing adaptive AMSDU aggregation based on the link bit error rate. Evaluations on a model show that instead of implementing a complex adaptive AMSDU frame aggregation mechanism which impact queuing and other implementation aspects, it is easier to influence packet error rate with traditional mechanisms while keeping the AMSDU aggregation logic simple.
Journal Article•
TL;DR: Simulation results show that frame aggregation is a powerful mechanism in terms of increasing system throughput through reducing overhead in MAC layer and the impact of frame aggregation on the system throughput is studied.
Abstract: Recently, the very high throughput (VHT) IEEE 802.11ac amendment has emerged as the fifth generation of wireless local area networks (WLANs). Enhancements to the physical and MAC layers have been defined which elevate the data rate to 6.933 Gbps. The 802.11ac amendment extends the frame size from 8000 bytes to approximately 11454 bytes, which increases the ability to aggregate frames from upper layers. Moreover, frame aggregation is employed in 802.11ac which states that all MAC protocol data units (MPDU) must use the aggregate MPDU (A-MPDU) format. In this paper we evaluate the techniques of frame aggregation adopted by IEEE 802.11ac. In particular, we study the impact of frame aggregation on the system throughput. Simulation results show that frame aggregation is a powerful mechanism in terms of increasing system throughput through reducing overhead in MAC layer.
TL;DR: Simulation results show that the proposed FAB scheme can significantly improve the performance of inter-vehicle communications.
Abstract: In vehicular ad hoc networks (VANETs), due to highly mobile and frequently changing topology, available resources and transmission opportunities are restricted. To address this, we propose a burst transmission and frame aggregation (FAB) scheme to enhance transmission opportunity (TXOP) efficiency of IEEE 802.11p. Aggregation and TXOP techniques are useful for improving transmission performance. FAB aggregates frames in the relay node and utilizes the TXOP to transmit these frames to the next hop with a burst transmission. Simulation results show that the proposed FAB scheme can significantly improve the performance of inter-vehicle communications.