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In cellular networks, proximity users may communicate directly without going through the infrastructure such as the base station (BS), which is device-to-device (D2D) communications, and it can improve spectral efficiency. However, enabling D2D communications in a cellular network poses two major challenges. First, the BS is suffered from signaling overhead. Second, D2D transmitters may cause harmful...
We consider a system of two nodes transmitting to an access point on quasi-static Rayleigh fading channels. We use signal-to-noise ratio (SNR) thresholds to characterize the requirements of each node, in terms of throughput and reliability, and we study their impact on outage probability. Given the average quality of the uplink channels, we formulate conditions on the SNR thresholds for decode-and-forward...
In this paper, an opportunistic cooperative HARQ system is analyzed. Different from prior analyses, time correlated fading channels are considered. Based on moment generation function and Laplace transform, the outage probability and throughput in terms of long-term average transmission rate (LATR) of this opportunistic cooperative HARQ system are derived in closed-forms. The accuracy of the analytical...
This paper proposes a scalable prototype surveillance/alarm ITS (Intelligent Transportation System) for roadways safety applications over roadway environments with emphasis given in the wireless vehicular communication inside a tunnel after an emergency event. A heterogeneous hybrid vehicular wireless network consisted of IEEE 802.11b/g/e and IEEE 802.16e is being deployed inside a tunnel environment...
In this paper buffer-aided Opportunistic Routing (OR) was designed with the aid of the novel concept of linear Transmission Activation Probability Space (TAPS) partitioning invoked for relay-assisted networks, which combines the benefits of both OR~\cite{ExOR2004} and of buffer-aided transmissions~\cite{6189806}. More specifically, a packet may be transmitted from the Source Node (SN) to the Destination...
Recently, we have studied frequency-domain space-time block coded joint transmit/receive diversity (FD-STBC-JTRD) for distributed antenna network (DAN). The channel of DAN can be modeled as doubly-selective (time- and frequency-selective) Nakagami-Rice fading channel. FD-STBC-JTRD requires accurate channel state information (CSI). However, in a high mobility environment, channel estimation is a problem...
Transmission over a half-duplex relay channel with secrecy and quality-of-service (QoS) constraints is studied. It is assumed that data is stored in buffers prior to transmission and transmitters operate with a constraint on the buffer overflow probability. Using the effective capacity formulation, secrecy throughput is derived for the half duplex two-hop fading relay system operating in the presence...
We introduce a modulated interfering signal in the guard band of a wireless packet based (infrastructure) network. Wireless networks, such as LTE, utilize orthogonal frequency division multiplexing (OFDM) and adaptive modulation and coding (AMC) at the physical layer, hybrid auto-repeat-request (HARQ) at the data-link layer, and cross-layer optimization to increase performance. Both the target and...
Proportional fair (PF) scheduling is known to provide a balance between overall throughput maximization and fairness, by ensuring that users are served at one point in time, even if they experience poor channel conditions. In this regard, the PF scheduler accounts for the current channel state as well as for the throughput a user previously obtained. However, in slow fading scenarios with feedback...
Coordinated multiple point transmission (CoMP) technology becomes popular due to its potential for improving the performance of cell-edge UEs who undergo strong inter-cell interference (ICI). To fully exploit the potential CoMP gain, the appropriate method to converge cells into cluster is a prerequisite. However, the majority of existing research are based on theoretical hexagonal cell grid model...
In this paper we investigate the role of tilt angle adjustment in next generation LTE networks where SIMO receivers and adaptive OFDM/TDMA transmission scheduling may additionally be used to mitigate interference. We present detailed performance measurements when (i) optimal fair tilt angle adjustment is applied in combination with SIMO receivers using Linear Minimum Mean Square Error (LMMSE) detection...
This paper discusses methods for improving the effectiveness of delivering voice traffic over High-Speed Downlink Packet Access (HSDPA) network by employing transmission diversity with Single-Frequency Dual-Cell (SF-DC) Aggregation that is part of the Multiflow specification. SF-DC Aggregation allows the user to be served at the same time by two different cells. The enhancements discussed in the paper...
Multi-hop relaying is an effective technique to combat the negative impacts of channel fading by providing shorter hops between peers in wireless networks. This paper investigates the modeling of a multi-hop Automatic Repeat reQuest (ARQ) system with Decode and Forward (DF) relaying. We propose a three-state Markov model, which is suitable for Rayleigh block fading channels. Analytical throughput...
There are advantages to retrieve information from the Wireless Sensor Network (WSN) for UAVs (Unmanned Aerial Vehicles). However, the UAV-WSN system has some differences with conventional WSN system. So it is important to design an appropriate scheme to control the transmission in a UAV-WSN system. In this paper we proposed a protocol called A-OAloha (Adaptive-Opportunistic Aloha) for UAV-UAV-WSN...
This work considers an simulated energy management for energy harvesting sensor nodes. There are four energy management, that is Optimal Offline Policy, Optimal Online Policy, Constant Water Level Policy, Adaptive Energy WF Policy, and Time-Adaptive Energy WF Policy. Energy harvest source that used in this paper is the sun energy. Optimal energy management is energy management that is able to keep...
Several technologies have been added to wireless communication systems that increase reliability of these systems and afford them higher data rates. These new technologies when combined with the multiple layers of a communications network make the analysis of these systems increasingly complex. The work here analyzes the impact of placing a modulated interfering transmission in the guard band of a...
Diversity gain can be achieved when cooperative transmission adopted in the wireless networks, which can provide much help to weak channel communication. Much has been done on the cooperative protocol and the performance analysis. In this paper, a new cooperative schedule is proposed. In which we have discussed three issues: when cooperative transmission should be adopted, how to choose the relay...
This paper investigates the achievable very high throughput (VHT) of the emerging IEEE 802.11ad standard operating at 60 GHz ISM band. The specified modulation and coding schemes are evaluated in a 60 GHz conference room channel. Two IEEE 802.11ad physical layers were considered namely, orthogonal frequency division multiplex (OFDM) physical layer and single carrier (SC). Evaluation was conducted...
CSMA/CA protocol shows poor performance for multi-hop transmission due to intra-flow interference (IFI) caused by hidden terminal (HT) problem. We propose an IFI-cancelling (IFIC) multi-hop transmission scheme which can efficiently relay packets under high traffic load and fading environment by using a Known interference cancellation technique. It employs the least mean square (LMS) equalization process...
This paper proposes a novel relay selection strategy based on the feedback beamforming (BF) information for 60GHz millimeter-wave (mmWave) wireless communication systems under non-line-of-sight (NLoS) condition. First, an approach of collecting instantaneous channel state information (CSI) through overheard during BF is devised. Second, with the aim of maximizing overall network throughput capacity,...
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