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When a mobile host transmitting real-time video traffic using DCCP CCID3 moves between two wireless LAN access points with different congestion situations, it is difficult to quickly change the transmission rate according to the changes of communication environment because controlling the sending rate depends on feedback information. To solve this problem, we recently proposed a predictive rate control...
In this paper, we discuss the challenges associated with integrating multiuser OFDMA in a single cell IEEE 802.11 based wireless ad hoc network and propose a new, dynamic and robust approach to improve it. Our new MAC, using OFDMA in the physical layer, can incorporate multiple concurrent transmissions or receptions in a dynamic manner and can adjust the collision probability based on the traffic...
In this paper we address the Quality of Service (QoS) issues for applications such as voice and video that generate bursty traffic in mobile ad hoc networks while asynchronous power saving protocols are applied to wireless hosts. To provide QoS, we propose our new quorum-based power saving protocol called "consecutive quorum-based power saving (CQPS)". Within this torus-based protocol each...
DCF (distributed coordination function) of IEEE802.11 MAC protocols uses binary exponential increasing mechanism, called BEB (binary exponential backoff) algorithm. Due to the lack of a mechanism evaluating the channel condition, it can not tune the value of contention windows adaptively, according to the actual network traffic. By introducing the network allocation vector count in routing protocol...
Nowadays, wireless networks have been deploying everywhere, with IEEE 802.11 as the most popular standard. However, wireless resources are scarce and wireless condition varies often. These limitations are crucial for applications with tight QoS requirements such as video or voice over IP. To cope with the problems, the standard has provided many features including multi-rate capability, which is the...
In this paper, we investigate a hybrid network coding technique to be used at a wireless base station (BS) or access point (AP) to increase the throughput efficiency of single-hop wireless networks. Traditionally, to provide reliability, lost packets from different flows (applications) are retransmitted separately, leading to inefficient use of wireless bandwidth. Using the proposed hybrid network...
In this paper, we introduce and evaluate ScaleMesh, a scalable miniaturized dual-radio wireless mesh testbed based on IEEE 802.11b/g technology- ScaleMesh can emulate large-scale mesh networks within a miniaturized experimentation area by adaptively shrinking the transmission range of mesh nodes by means of variable signal attenuators. To this end, we derive a theoretical formula for approximating...
In this work, we focus on a WLANs mesh, i.e., an ad hoc, IEEE 802.11-based network whose nodes are either user devices or access points providing access to the mesh network or to the Internet. By relying on some work about IEEE 802.11 MAC analysis, we consider mesh-DQDC protocol and present an analytical model of the MAC scheme, through which we show that the protocol achieves high throughput both...
Knowledge of the error process and related channel parameters in wireless networks is invaluable and highly instrumental in a broad range of applications. Under the IEEE 802.15.4 Low Rate-Wireless Personal Area Networks (LR- WPAN) standard, compliant devices are capable of providing two pieces of information about the channel conditions along with each received packet, the Link Quality Indication...
With recent improvements in physical layer (PHY) techniques, the achievable capacity for wireless LANs (WLANs) has grown significantly. However, the overhead of IEEE 802.11 MAC layer has limited the actual throughput of a WLAN. A-MPDU aggregation suggested in IEEE 802.11n draft is a key enhancement reducing the protocol timing overheads that enables aggregation of several MAC-level protocol data units...
In this paper, we address the issue of transmission power control (TPC) in wireless ad hoc networks. Power control plays an important role in energy saving and network performance enhancement. However, the existing TPC schemes either face the problem of hidden and exposed terminal or have additional hardware requirements. We propose a novel distributed power control protocol, called Receiver Initiated...
In this paper, we propose an adaptive pacing scheme at the link layer for IEEE 802.11 based multihop wireless networks. Our objective is to improve the performance of higher layer protocols without any modifications to them. Our adaptive pacing scheme estimates the four-hop transmission delay in the network path without incurring any additional overheads, and accordingly paces the packets to reduce...
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