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The Quality of Service (QoS) on the traffic environment with high mobility, dynamic topology, and change trajectory is one of the challenges in the use of Vehicular Ad-Hoc Networks (VANET) Routing Protocols. PUMA routing protocol presents multicast work mechanism based on shared mesh topology. It always dynamically adapt to VANET traffic conditions. In this paper, we evaluated the PUMA routing protocol...
In this paper, we develop a queueing analysis for opportunistic decode-and-forward (DF) relay networks. It is assumed that the networks undergo Nakagami-m fading and that the external arrival process follows a Poisson distribution. By selecting the best relay according to the opportunistic relaying scheme, the source first transmits its signal to the best relay which then attempts to decode the reception...
A relay diversity scheme is proposed to provide diversity gain and better system performance in wireless fading environment. The hybrid relay diversity (HRD) scheme combines the concept of distributed space-time block coding (DSTBC) and relay cyclic delay diversity (RCDD) for OFDM-based relay communication network with more than one relay nodes. The scheme addresses the issue of achieving maximum...
In-band spectrum sensing requires that the secondary users (SU) periodically suspend their communication in order to determine whether the primary user (PU) has started to utilize the channel or not. In contrast, in spectrum monitoring the SU can detect the emergence of the PU from its own receiver statistics such as receiver error count (REC). Previously it is shown that in AWGN channels, a hybrid...
Time-reversed orthogonal frequency division multiplexing (TR-OFDM) has recently received attention as a promising scheme for supporting single-input multiple-output (SIMO) communications over time-dispersive fading channels. In TR-OFDM, the time reversal processing cleverly converts multiple time-dispersive fading channels associated with SIMO-OFDM into a single channel with generally smaller time...
Traditional OFDM systems present some embedded features that may be exploited in order to intercept the wireless transmitted signal. However, such a possibility is not accepted in military applications where security is a very important issue. Cyclic prefix is one of the most obvious OFDM parameters that induce cyclostationarity features. Aiming to suppress these features, some classical solutions...
In this paper, we analyse the delay performance of a point-to-multipoint cognitive radio network which is sharing the spectrum with a point-to-multipoint primary network. The channel is assumed to be independent but not identically distributed and has Nakagami-m fading. A constraint on the peak transmit power of the secondary user transmitter (SU-Tx) is also considered in addition to the peak interference...
In this paper bit error rate (BER) performances of the built-in MATLAB multipath fading simulator, which recreates a theoretical channel based on user's specified parameters, have been compared to that of a ‘playback’ based channel simulator. The MATLAB fading simulator has been configured with parameters estimated from the same radio channel measurements used by the ‘playback’ based simulator. The...
In recent years, the performance analysis of UWB (Ultra-Wide Band) systems has been an area of considerable interest. To understand the fading in UWB caused by the multipath propagation in complicated environment of underground mines, a precise model of the channel response is expected for designing a UWB system. This paper presents the comparison between the UWB channel proposed by study group IEEE...
TH (Tomlinson-Harashima) precoding is an important nonlinear precoding method. In this paper, the bit error rate (BER) performance for the TH precoding system is investigated over time varying and dispersive Ricean fading channels. Assuming that there exists a certain delay introduced by the feedback channel, we first model the feedback error of channel station information (CSI) due to the feedback...
In this paper, confronting the frequency-selective fading in the channel of unmanned aerial vehicle (UAV), the technology of single-carrier frequency domain equalization (SCFDE) which can resist to the frequency selective fading is discussed for minimum shift keying (MSK). And then, a channel model is discussed for UAV and the composition of the UAV communication channel is analyzed. What's more,...
Coordinated multi-point (CoMP) transmission is considered as an efficient technique to improve cell-edge performance as well as system spectrum efficiency. In CoMP-enabled systems, a cluster of coordinated base stations (BSs) are typically assumed to be connected to a control unit (CU) via backhaul links, and the provided performance gain relies heavily on the quality of the channel state information...
In this paper, we examine the performance of multiple-input multiple-output (MIMO) cognitive amplify-and-forward (AF) relay systems with maximum ratio transmission (MRT). In particular, closed-form expressions in terms of a tight upper bound for outage probability (OP) and symbol error rate (SER) of the system are derived when considering channel estimation error (CEE) and feedback delay (FD) in our...
This paper studies a spectrum sharing cognitive radio (CR) network coexisting with a primary network. In particular, the channel state information (CSI) between the secondary transmitter (STx) and the primary receiver (PRx) is assumed to be outdated due to channel feedback latency. We assume that the secondary user (SU) shall satisfy a given delay quality-of-service (QoS) constraint as well as the...
Carrier aggregation (CA) has been proposed as a key feature of the 4G cellular networks to achieve the very high data rates. It is known that the correlation between the subchannels, including both small- and large-scale fading, is critical in determining the performance gain we can obtain from the multicarrier transmission. However, due to the prohibitively high complexity and cost in simultaneously...
This paper considers multiuser cooperative relay networks with user selection at the mobile station, where both the relay and mobile users are corrupted by a finite number of co-channel interferers. We study the impact of the outdated channel state information (CSI) on the system performances over time-varying Rayleigh fading channels by deriving the tight lower bounds for the outage probability and...
In this paper we propose an algorithm to achieve hard delay constraints in OFDMA systems. The resource scheduler has to ensure that delay deadlines of the packets get achieved and the resources are also not under utilized. This is a very difficult task since the channel and packet arrival in user queues are time varying in nature. The instantaneous decisions of scheduler depend on current as well...
We propose a new transmission protocol for two-hop transmission employing rateless coding in the first hop and rateless-network coding in the second hop. In this protocol, communicating pairs (CP) and also relays are partitioned into small clusters; afterwards, each CP-cluster is assigned one relay cluster to improve data transmission. This scheme increases the diversity order (in comparison to the...
Multiple Description (MD) source coding is a technique that breaks a media stream into equally important sub-streams which can be sent over different paths for protection against channel errors in wireless networks. In this paper, we explore the possibility of sending the descriptions through different paths and intermediately merging them to exploit recovery of the corrupted descriptions from the...
The impulse ultra-wideband (UWB) channels covering the frequency range from 2 to 10 GHz, it covers indoor residential, door office, outdoor, industrial, and open outdoor environments. UWB communications systems share the spectrum with other systems in an unlicensed manner. This has caused a strict spectral constraint. In order to discuss power spectrum distribution, it analyzed the channel modeling...
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