Showing papers on "Frame aggregation published in 2006"
01 Nov 2006
TL;DR: An analytical model is proposed to study the performance improvement of the MAC protocol by using the two frame aggregation techniques, namely A-MPDU and A-MSDU (MAC Service Data Unit Aggregation) and results show that the network throughput performance is significant improved when compared with both randomized and fixed frame aggregation algorithms.
Abstract: The IEEE 802.11a/b/g have been widely accepted as the de facto standards for wireless local area networks (WLANs). The recent IEEE 802.11n proposals aim at providing a physical layer transmission rate of up to 600 Mbps. However, to fully utilize this high data rate, the current IEEE 802.11 medium access control (MAC) needs to be enhanced. In this paper, we investigate the performance improvement of the MAC protocol by using the two frame aggregation techniques, namely A-MPDU (MAC Protocol Data Unit Aggregation) and A-MSDU (MAC Service Data Unit Aggregation). We first propose an analytical model to study the performance under uni-directional and bi-directional data transfer. Our proposed model incorporates packet loss either from collisions or channel errors. Comparison with simulation results show that the model is accurate in predicting the network throughput. We also propose an optimal frame size adaptation algorithm with A-MSDU under error-prone channels. Simulation results show that the network throughput performance is significant improved when compared with both randomized and fixed frame aggregation algorithms.
239 citations
11 Dec 2006
TL;DR: The results indicate that the choice of aggregate size not only depends on the traffic arrival rate, but also on data frame sizes, which calls for a dynamic assignment of aggregate sizes.
Abstract: Frame aggregation is one of the several enhancements proposed by IEEE 802.11 Task Group n to improve channel utilization. In frame aggregation, more than one data frame is encapsulated to form an aggregate, and once an aggregate is formed, a station contends to access the medium to transmit the entire aggregate. We refer to the number of data frames encapsulated within an aggregated frame as aggregate size. We claim that a static assignment of aggregate size leads to the following performance trade-off: a small value might be insufficient to mitigate the transmission overheads, thereby nullifying the whole purpose of frame aggregation; whereas, a large value might affect the quality of service experienced by higher layers due to the extra wait time to build an aggregate. In this paper, we characterize this trade-off by studying the impact of aggregate size on metrics like frame latency and channel utilization. To estimate these metrics, we model the transmission queue of an 802.11n station as a bulk service queuing system. We study the impact of aggregate size over a wide range of operating conditions covering several traffic arrival rates from higher layers, service distribution and data frame sizes. Apart from validating the existence of above-mentioned performance trade-off, our results indicate that the choice of aggregate size not only depends on the traffic arrival rate, but also (more interestingly) on data frame sizes. This calls for a dynamic assignment of aggregate size.
46 citations
14 Nov 2006
TL;DR: A queuing system approach is used to extend the discussions of IEEE 802.11 protocol throughput and delay limits to the situation that arbitrary non-saturated background traffic is present in the network, and derive analytical models to quantify the performance limits.
Abstract: Recent advance in IEEE 802.11 based standard has pushed the wireless bandwidth up to 600Mbps while keeping the same wireless medium access control (MAC) schemes for full backward compatibility. However, it has been shown that the inefficient protocol overhead casts a theoretical throughput upper limit and delay lower limit for the IEEE 802.11 based protocols, even the wireless data rate goes to infinitely high. Such limits are important to understand the bottleneck of the current technology and develop insight for protocol performance improvements. This paper uses a queuing system approach to extend the discussions of IEEE 802.11 protocol throughput and delay limits to the situation that arbitrary non-saturated background traffic is present in the network. We derive analytical models to quantify the performance limits for Distributed Coordination Function (DCF) of legacy 802.11a/b/g and Enhanced Distributed Coordination Access (EDCA) of IEEE 802.11e. We find such limits are functions of the underlying MAC layer backoff parameters and algorithms, and are highly dependent on the load that background traffic injects into the network. Depending on the rate of arrival traffic, the packet delay limit may become unbounded such that no delay sensitive services can be operated under such condition. Moreover, we also discuss the effects of different frame aggregation schemes on the performance limits when data rate is infinite. The developed model and analysis provide a comprehensive understanding of the performance limitations for IEEE 802.11 MAC, and are useful in gauging the expected QoS for the purposes such as admission control.
38 citations
11 Dec 2006
TL;DR: This paper argues that existing opportunistic schemes are not optimal when frame aggregation is used, and proposes new scheduling approaches that combine channel states with queue states that offer significant improvement in network throughput over non-opportunistic and greedy schedulers.
Abstract: The multiuser diversity phenomenon is exploited via opportunistic scheduling for increasing system throughput in wireless networks. Another method to enhance system throughput is through frame aggregation, which increases MAC efficiency. We consider opportunistic scheduling jointly with frame aggregation. In this paper, we argue that existing opportunistic schemes are not optimal when frame aggregation is used. We propose new scheduling approaches that combine channel states with queue states. Through detailed simulations, we show that our new algorithms offer significant improvement in network throughput over non-opportunistic and greedy schedulers. Our algorithms also provide a good compromise between throughput and fairness.
15 citations
TL;DR: A novel frame aggregation scheme to improve MAC efficiency was proposed and it was found that the measured throughput of more than 170Mbit/sec was achieved using the proposed frame aggregation.
Abstract: We developed a high speed wireless LAN prototype in the 5GHz band. Maximum transmission rate of the developed WLAN equipment was 324Mbit/sec using 6 multi-channels of 802.11a. We proposed a novel frame aggregation scheme to improve MAC efficiency. The proposed frame aggregation scheme had a feature of an adaptive aggregation size selection depending on thewireless channel conditions and application requirements. Throughput performance was obtained from simulation using a multiple station system with the proposed frame aggregation. A throughput of more than 150Mbit/sec was achieved with an evaluated system of 10 STAs. We also found that the measured throughput of more than 170Mbit/sec was achieved using the proposed frame aggregation.
14 citations
Journal Article•
TL;DR: This paper proposes an efficient design of CCMP for IEEE 802.11i to support new MAC mechanisms and adopts the mode toggling approach, in which MIC calculation and data encryption are sequentially performed for each 128 bits of the packet in only one AESCCM core.
Abstract: For high data rate, new mechanisms such as Block Ack and frame aggregation are currently being discussed in IEEE 802.1 1e and IEEE 802.1In, respectively. These mechanisms need a short response time in each MPDU processing. In this paper, we propose an efficient design of CCMP for IEEE 802. 11i to support these new MAC mechanisms. The proposed design adopts the mode toggling approach, in which MIC calculation and data encryption are sequentially performed for each 128 bits of the packet in only one AES-CCM core. In our design, the response time is reduced to a short constant period, which takes only 44 clock cycles. In addition, we can reduce hardware complexity and power consumption, because our design uses one AES-CCM core and obtains the reasonable data throughput and response time at even low clock frequency. We have implemented the proposed design, which is targeted to Altera Stratix FPGA device. As a result of the experiments, the CCMP features 285 Mbps data throughput and 0.88 us response time at 50 MHz frequency.
11 citations
03 Jul 2006
TL;DR: This article extends the established 802.11 analytical models to include the frame bursting feature and presents guidelines for implementing fair adaptive algorithms that use TXOP.
Abstract: Several enhancements to the Medium Access Control (MAC) layer of the IEEE 802.11 standard have been recommended in the new 802.11e standard. One main enhancement is the possibility to send bursts of frames during a limited duration called Transmission Opportunity (TXOP). Similar MAC efficiency enhancements such as Frame Aggregation have also been proposed for the upcoming 802.11n standard. We analyze the application of this feature to the existing 802.11 MAC and evaluate its performance under different network conditions. The frame bursting feature can increase the total capacity of an 802.11 network by reducing the contention and collision for bursty traffic sources. We extend the established 802.11 analytical models to include the frame bursting feature. Through simulation experiments we analyze the delay performance of the network under different frame bursting options and show that while in general frame bursting is useful and can increase the system capacity, it might cause excessive unfairness in certain cases. Using the findings of this article we present guidelines for implementing fair adaptive algorithms that use TXOP.
10 citations
11 Dec 2006
TL;DR: It is found that throughput of the developed equipment was measured to be more than 170 Mbit/sec using the proposed frame aggregation, which had a feature of an adaptive aggregation size selection depending on wireless channel conditions and application requirements.
Abstract: We developed a high speed wireless LAN prototype in the 5 GHz band. Maximum transmission rate of the developed WLAN equipment was 324 Mbit/sec using 6 multi-channels of 802.11a. We proposed a novel frame aggregation scheme to improve MAC efficiency. The proposed frame aggregation scheme had a feature of an adaptive aggregation size selection depending on wireless channel conditions and application requirements. Throughput performance was simulated in the case of multiple stations with the proposed frame aggregation. The evaluated system throughput was achieved more than 150 Mbit/sec in the case of 10 STAs. It is found that throughput of the developed equipment was measured to be more than 170 Mbit/sec using the proposed frame aggregation
10 citations
Patent•
12 May 2006
TL;DR: In this paper, a frame aggregation format and method for efficient data transmission in wireless communications is proposed, which is not backward compatible with existing frame formats, but provides a new structure for a MAC Protocol Data Unit (MPDU).
Abstract: In a wireless mesh network (10) a frame aggregation format and method for efficient data transmission in wireless communications. The frame aggregation is not required to be backward compatible with existing frame formats, but provides a new structure for a MAC Protocol Data Unit (MPDU) .
10 citations
03 Apr 2006
TL;DR: Implementation and analysis of frame aggregation show that it improves the performance of voice over IP (VoIP) operating on IEEE 802.11 considerably.
Abstract: In recent years, there has been a lot of interest in using wireless local area networks (WLAN) for voice communications with the expanded coverage of hot spots. This paper describes packet aggregation method that increases the throughput of WLAN for voice communication by decreasing the overhead of backoff at the beginning of each packet transmission. Aggregation allows AP to acquire the channel and send its packets inside a multicast packet or back-to-back. Implementation and analysis of frame aggregation show that it improves the performance of voice over IP (VoIP) operating on IEEE 802.11 considerably
10 citations
13 Feb 2006
TL;DR: It is found that high throughput of more than 170Mbit/sec was achieved using the proposed frame aggregation, which features an adaptive aggregation size selection depending on wireless channel conditions and application requirements.
Abstract: We developed a high speed wireless LAN prototype in the 5GHz band that is backward compatible with legacy IEEE802.11a. The developed WLAN equipment has a data rate of 324Mbit/sec using 6 PHY transmission channels of 802.11a. We propose frame aggregation to improve MAC efficiency. The proposed frame aggregation features an adaptive aggregation size selection depending on wireless channel conditions and application requirements. The optimal frame aggregation size for the PHY data rate is evaluated by using computer simulation. MAC throughput as a function of aggregation size was simulated and measured. We find that high throughput of more than 170Mbit/sec was achieved using the proposed frame aggregation.
Patent•
23 Feb 2006
TL;DR: In this article, the authors present methods, devices and computer program products for scheduling of acknowledgement by a communication station that is configured to operate in a communications system that supports frame aggregation.
Abstract: Methods, devices and computer program products for scheduling of acknowledgement by a communication station that is configured to operate in a communications system that supports frame aggregation. Communication stations can determine when to schedule acknowledgements based on aggregated frame information.
26 Jun 2006
TL;DR: This paper shows that over IEEE 802.11 WLANs, voice frame aggregation should better be done at the AP, over a single call, and without additional delay, and demonstrates through simulation and analysis that this particular implementation choice enables us to support far more VoIP calls on 802.12b than other choices.
Abstract: To solve the poor bandwidth efficiency problem of VoIP over IEEE 802.11 wireless LANs (WLANs), the literature frequently suggests elongating voice payload size. Such "voice frame aggregation" can be performed (1) over a single call or multiple calls, (2) at the voice source or at the wireless access point (AP), and (3) with additional repacketization delay or without it. This paper shows that over IEEE 802.11 WLANs, voice frame aggregation should better be done at the AP, over a single call, and without additional delay. We demonstrate through simulation and analysis that this particular implementation choice enables us to support far more VoIP calls on 802.11 WLANs than other choices. For one instance, we show that 100 or more G.729 calls are possible on 802.11b within ITU-T recommended delay bounds.
Patent•
20 Dec 2006TL;DR: In this paper, the current state of a terminal is converted into sleep mode after the terminal collectively processes data transceiving by periodically or non-periodically waking up according to each service characteristic.
Abstract: A power-saving device in a wireless communication system and a method thereof are provided to make the current state of a terminal converted into a sleep mode after the terminal collectively processes data transceiving by periodically or non-periodically waking up according to each service characteristic, thereby reducing power consumption of the terminal. A protocol controller(205) generates the first control information frame which notifies an access point of wake-up when the wake-up occurs in sleep mode, and generates the third control information frame which includes receivable period information when the second control information frame, including requested transmission period information of the access point, is received. A frame aggregation controller(207) aggregates the third control information frame and user data frames to be transmitted, into one protocol data unit, and delivers the aggregated protocol data unit to a physical layer.
25 Oct 2006
TL;DR: A novel MAC scheme is proposed that utilizes MIMO distributed spatial multiplexing to solve all the aforementioned problems, resulting in high throughput and fairness in multi-hop wireless ad hoc networks, and can be integrated with frame aggregation to further enhance the network performance.
Abstract: Nowadays, the prevalence of multimedia applications mandates that wireless networks provide higher throughput and increased spatial efficiency. Aimed primarily at achieving this goal, the first IEEE 802.11n draft was recently approved. In the draft, MIMO and frame aggregation are utilized to improve the PHY and MAC layers in single-hop WLANs by achieving high raw rates and goodput. However, in the context of multi-hop wireless ad hoc networks, the hidden terminal, exposed terminal, and deafness problems remain unsolved by IEEE 802.11n. Consequently, this greatly degrades the MAC efficiency in multi-hop wireless ad hoc networks, even in the presence of frame aggregation. In this paper, we propose a novel MAC scheme that utilizes MIMO distributed spatial multiplexing to solve all the aforementioned problems, resulting in high throughput and fairness in multi-hop wireless ad hoc networks. Moreover, our scheme can be integrated with frame aggregation to further enhance the network performance.
TL;DR: To solve the energy-efficiency problem while still maintaining good quality of service, this paper proposes a TDMA-based Medium Access Control protocol, with enhanced features allowing to save energy such as deterministic scheduling and frame aggregation.
05 Oct 2006
TL;DR: The idle while counting down the backoff time was been converted to advantage for frame scheduling in this paper to eliminate the decomposition of aggregated frame to multi-destination.
Abstract: For the overheads of 802.11 WLAN, several frame aggregation mechanisms had been proposed to deal with this shortcoming. Since the rare consideration of QoS in these proposals, we took advantage of 802.11e queueing model to enhance the priority scheduling. This paper approaches to eliminate the decomposition of aggregated frame to multi-destination. The idle while counting down the backoff time was been converted to advantage for frame scheduling in this paper.
01 Sep 2006
TL;DR: The result shows that SCFA on 802.11-based multi-hop network can boost the number of calls approximately twofold, or extends the hop distance threefold for a given number of Calls to carry.
Abstract: In multi-hop wireless networks, the number of supportable VoIP calls can be surprisingly small due to the increased spatial interference. To mitigate the interference, voice frame aggregation can be used. In this paper, we depart from the traditional approaches that perform aggregation at the voice source, and propose a technique called the self-controlled frame aggregation (SCFA) that runs at wireless routers. The core idea of SCFA is to let the congestion itself control the degree of aggregation. Unlike existing frame aggregation approaches, SCFA does not incur fixed delay cost, since it is used only when and by exactly as much as it is needed. In this paper, we take the example of 802.11-based multi-hop network to show the impact of SCFA, since many emerging multi-hop networks are built on the 802.11 technology. The result shows that SCFA on 802.11-based multi-hop network can boost the number of calls approximately twofold, or extends the hop distance threefold for a given number of calls to carry.
TL;DR: A new mechanism for IEEE 802.11 infrastructure networks that allows to save energy on battery powered devices by adding some processing on the wireless Access Point (AP) by improving the link Quality of Service (QoS) by providing better throughput and latency for a given number of stations.
Abstract: This paper introduces a new mechanism for IEEE 802.11 infrastructure networks that allows to save energy on battery powered devices by adding some processing on the wireless Access Point (AP). Although the main advantage of this mechanism is energy efficiency, it aims at improving the link Quality of Service (QoS) by providing better throughput and latency for a given number of stations, in comparison to IEEE 802.11 regular performance. The power saving mode integrated in IEEE 802.11 standard is very power efficient, however it is not usable in realtime communications because it adds too much latency. In addition our optimisation can be implemented on an AP without preventing regular stations from operating with this AP, and it allows for mixed operation of both regular and optimised rotocols.
01 Jan 2006
TL;DR: An analytic method to estimate the utilization for RTS/CTS-based contention access mechanism with unidirectional or bidirectional aggregation with results to show the accuracy of the analytic model.
Abstract: The IEEE 802.11 MAC provides a method for multiple users to share the wireless media. The channel utilization is limited because of protocol overhead no matter how fast the payload is transmitted. To increase utilization, frame aggregation is a straightforward way to improve the channel efficiency. This paper presents an analytic method to estimate the utilization for RTS/CTS-based contention access mechanism with unidirectional or bidirectional aggregation. Simulation results are also provided to show the accuracy of the analytic model.
01 Nov 2006
TL;DR: A high-level architecture exploration methodology for real-time application, which is IEEE 802.11n, where MAC and PHY are considered to be implemented in BUS based multi-processor SoC platform and transaction level model of the total system is generated using SystemC.
Abstract: This paper proposes a high-level architecture exploration methodology for real-time application, which is IEEE 80211n Both MAC and PHY are considered to be implemented in BUS based multi-processor SoC platform DCF with frame aggregation is applied as operational case Transaction level model of the total system is generated using SystemC in order to evaluate the real-time constraint and the system performance by different configurations