The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, we investigate the outage performance of decode-and-forward (DF) based opportunistic cooperative communications with channel estimation errors at the receivers under Rayleigh fading channels, in which the effect of the direct link has been explicitly evaluated. To be specific, the exact expression of outage probability has been derived for arbitrary values of signal-to-noise ratio (SNR)...
Long Term Evolution (LTE) is the latest step towards the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the possibility to transmit Multimedia Broadcast multicast service over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted...
IEEE 802.11 Wireless Local Area Network (WLAN) Physical Layer (PHY) offers multiple data rates. In multi-rate WLANs, 802.11 Medium Access Control (MAC) protocol, Distributed Coordination Function (DCF), essentially provides equal transmission opportunities to each sender host, causing the degradation of system throughput due to some hosts using low rates. In this paper we propose a cross-layer link...
The next generation wireless networks will comprise interworking heterogeneous wireless access network technologies. The interworking of these networks will enable access ubiquity, hence mobility, particularly vertical handover between the networks becomes topical. Thus, coordination within this diverse environment in terms of handover management is required to improve the handover performance. Furthermore,...
While Performance Enhancement Proxy (PEP) is a promising solution for TCP's performance issues over satellite links, it has a serious constraint in terms of a translation table limit of 500 entries that proved to be detrimental when a large number of TCP sessions need to be maintained between endpoints. We experienced one of these cases in Saudi Aramco where web-based drilling applications were establishing...
Selective decode and forward (SDF) based cooperative relaying protocol can provide full diversity. But SDF protocol requires bandwidth consuming cyclic redundancy check (CRC) bits to prevent error propagation from the relay. Link adaptive regenerative relaying (LAR) scheme avoids the need for CRC bits to reduce the error propagation from relay and can provide full diversity. But in the conventional...
Cooperative communications achieve tremendous improvements in system performance. Meanwhile, it tends to change the conventional access and transmission schemes in wireless networks. Thus, CoopMAC is proposed and analyzed for fully connected WLANs. It improves the performance of the network dramatically by enabling additional collaboration from other nodes. However, how does it work in multi-hop Ad...
This paper proposes a novel interference cancellation algorithm for the two-path succussive relay system using network coding. The two-path succussive relay scheme was proposed recently to achieve full date rate transmission with half-duplex relays. Due to the simultaneous data transmission at the relay and source nodes, the two-path relay suffers from the so-called inter-relay interference (IRI)...
P2P SIP (peer to peer session initiation protocol) systems have emerged as a new trend in multimedia realm due to their abilities to overcome the shortcomings of conventional SIP systems. Most of P2P SIP systems were implemented using Chord, a Distributed Hash Table (DHT) based routing algorithm which can provide scalability and reliability. Previous studies on P2P SIP systems did not address node...
MCN-MR (Multi-hop Cellular Network - Mobile Relay) has been proposed as a promising technology for future Beyond 3G and 4G systems due to its foreseen capacity to increase transmission rates and provide homogeneous quality of service levels in the service area. To this aim, mobile nodes are required to cooperate in the relaying of information of other nodes. As a result, selfish nodes refusing to...
Barrage relay networks (BRNs) are mobile ad hoc networks designed from the ground up to meet the demands of tactical edge communications. The fundamental building block of BRNs is not a point-to-point wireless link, but rather a rapid and robust broadcast mechanism that employs an autonomous cooperative communications scheme. Following a summary of basic BRN concepts, this paper demonstrates how the...
In wireless ad hoc networks, multiple access interference is the limiting factor for the overall system performance. The lack of any central control unit necessitates a careful joint design of both, the physical and the MAC layer. Two promising technologies that address this problem are power control based cross-layer design and multiuser detection based cross-layer design. While approaches in the...
The paper proposes a network coded cooperation protocol for the uplink transmission of relay assisted cellular networks characterized by non-ideal source - relay links. The proposed protocol employs Reed Solomon codes as network codes in order to improve the Block Error Rate (BLER) and Bit Error Rate (BER) performance over the slow varying fading channels. The paper presents also an algorithm for...
A base station (BS) transmits (Tx) and receives (Rx) signals to and from multiple mobile users (MU) through a two-way amplify and forward (AF) relay station (RS) using a two-phase protocol. The BS and the RS are both equipped with multiple antennas. In the first phase (time or frequency), the BS and all MU transmit their signals to the RS. In the second phase, the relay transmits towards the BS and...
In this paper, we propose a double space-time transmit diversity (DSTTD)-based two-path relay system with power allocation and link combining methods. The two-path relaying protocol can restore spectral efficiency decreased due to the half-duplexing at the relay nodes and the DSTTD method can appropriately achieve the diversity gain from the two paths. To circumvent severe performance degradation...
This paper presents a new cooperative ARQ with a distributed relay selection that exploits overhearing of inter-relay channels to achieve higher diversity during retransmission. The relays employ decode and forward (DF) to establish the link between the source and the destination. Upon reception from the source, the number of relays available to contend for transmission depends on the conditions of...
A two-way relay channel with independent parallel Gaussian channels between the relay and the two terminals is considered. Focusing on the decode-and-forward protocol, the second phase of the communication, in which the relay broadcasts the two messages to their respective receivers, is studied. Precisely, the problem of computing the power allocation among the parallel channels that maximizes the...
This paper addresses the fairness of Medium Access Control (MAC) protocols that are capable of handling interference on the physical layer to a varying extent. The variation addressed is thereby not based on different physical layer techniques applied, but on differing attribute levels of the same physical layer technique. This can e.g., be a varying number of antennas at each node in case of Multiple...
For multicast applications with large-scale groups in large-scale wireless sensor networks, it is an important issue for energy saving in geographic multicasting both to obtain location information of destination nodes and to construct the geographic multicast tree efficiently. To address this issue, there have been proposed global search based hierarchical geographic multicasting protocols. Such...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.