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In this paper, we investigate automatic repeat request (ARQ) protocols for a two-way amplify-and-forward relaying system. We first propose an outage-efficient ARQ protocol which exploits two-way retransmission for failure of reception at both terminals and one-way retransmission for failure of reception at only one terminal. This scheme significantly reduces the outage probability of the system at...
Heterogeneous Network (HetNet) where small cells served by Low Power Nodes (LPNs) are overlaid onto conventional macro cells is considered to meet the requirements of the increasing need for higher data rates. In this paper, we investigate the uplink interference situation in 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) HetNet and the corresponding impacts on the efficiency...
One of the challenges facing the next-generation wireless networks is to cope with the expected demand for data. This calls for an efficient spectrum regulation that can enable mobile subscribers to support high quality of service (QoS) and mobile network operators (MNOs) to leverage their profit streams. In this paper, we present a new spectrum allocation policy in a monopoly situation. The problem...
In this paper, transmit antenna selection (TAS) is applied to space shift keying (SSK) modulation to obtain diversity gain. The receiver selects a transmit antenna subset in each transmission block according to the channel state information (CSI) and sends the subset index to the transmitter through feedback. Several antenna selection schemes are evaluated for SSK from perspectives of performance,...
This paper proposes a relaying protocol which combines a network coding with a mobility of small unmanned aircraft (UA) for wireless relay networks. We consider the scenario where the UA circles above around the networks automatically and bridges the signals between ground access points (GAPs) of the distant networks. Such wireless relay networks using UA can be considered particularly useful for...
This paper adresses the problem of cooperation application in an existing non-cooperative wireless sensor network. Sensors are low-energy and low-data rate devices. They transmit small independent individually-encoded information packets to the same destination. The cooperation scheme is based on a product code distributed among sources and relays and turbodecoded at the destination. We propose a...
Recent advances in wireless technologies have enabled many new applications in Intelligent Transportation Systems (ITS) such as collision avoidance, cooperative driving, congestion avoidance, and traffic optimization. Due to the vulnerable nature of wireless communication against interference and intentional jamming, ITS face new challenges to ensure the reliability and the safety of the overall system...
Vehicular channels are among the most challenging wireless channels due to their high Doppler frequencies and multiple path delays. To meet these challenges, the IEEE standard 802.11p was developed. To improve performance, a vast variety of extended receiver concepts has been proposed and evaluated under different test conditions. In this paper, we study the two most promising standard-compliant receiver...
In this paper it is presented a proposal to increase the capacity of Down-Link (DL) transmissions in Long Term Evolution (LTE) like systems based on Multiple-Input Multiple-Output (MIMO)-Orthogonal Frequency Division Multiplexing (OFDM). The augment of the data rate is achieved with the total or partial suppression of the Cyclic Prefix (CP), which requires the use of a variable number of samples without...
Abstract--- Limited feedback precoding (LFP) significantly improves multiple-input multiple-output (MIMO) spatial multiplexing link reliability with a small amount of feedback from the receiver back to the transmitter. One of the key problems linked to LFP is how to select an optimal precoder from a pre- determined unitary codebook. We find that the conventional precoder selection criteria are not...
Single carrier frequency division multiple access (SC-FDMA), a multiple user access scheme based on the single carrier frequency domain equalization (SC-FDE) technique, has been proposed for the uplink in fourth generation (4G) mobile communications. SC- FDE requires reliable channel estimates to maintain an acceptable bit error rate (BER) performance. Much research focuses on the use of pilot symbols...
Modern vehicles will have strong requirements with regard to seamless mobility support in future cellular systems, in order to enable advanced cooperative driver assistance and infotainment systems that guarantee traffic safety and efficiency. In this work, we introduce street-specific handover parameters for vehicular terminals. In particular, we propose an adaptive optimization algorithm that exploits...
In this paper, we study single cell multi-user downlink distributed antenna systems (DAS) where antenna ports are geographically separated in a cell. First, we derive an expression of the ergodic sum rate for the DAS in the presence of pathloss. Then, we propose a transmission selection scheme based on the derived expressions which does not require channel state information at the transmitter. Utilizing...
Estimating the available bandwidth in IEEE 802.15.4-based networks is a difficult and challenging task due to the shared nature of the wireless communication medium. The MAC layer decides the sharing of a communication medium, therefore the MAC layer dictates the amount of bandwidth available to a node. Some recent solutions consider the impact of the MAC layer back-off due to collision and transmitter...
In multi-user MIMO systems, coordinated beam- forming can be used to relax the dimensional constraint of block diagonalization and accommodate more users. However, coor- dinated beamforming and other similar beamforming schemes require coordination of information from the base station to the users, which requires user specific reference signals. Moreover, coordinated beamforming methods have high...
Wireless Mesh Networks (WMNs) integrate fast deployable backbone networks and distributed mobile ad hoc networks with self-healing, self-organization and self-configuration features. These capabilities make WMNs a promising technology for emergency management communications. An incident area network needs reliable routing paths during disaster recovery and emergency response operations, when pre-existing...
The main challenge when providing quality of services in future mobile networks is the low signal quality regimes, mainly experienced by the users located at the cell edge. The deployment of relay nodes promises significant improvement of the received signal quality and enables the establishment of QoS-aware services for such users. In this work, we propose and study the performance of a novel QoS-aware...
In this paper, the analysis for the average bit error probability (ABEP) of a dual-hop fixed-gain relay network is conducted. To this end, we consider two different scenarios: 1) the second hop (relay- destination link) is subject to composite multipath/shadowing and the first hop (source-relay link) experiences only multipath fading; 2) the first hop is perturbed by the composite multipath/shadowing...
This paper investigates the influence of channel state information (CSI) error at the transmitter on the achievable throughput of our previously reported layered partially non-orthogonal block diagonalization (BD) precoding method with adaptive interference admission control (AIAC) for downlink multiuser (MU) multiple-input multiple-output (MIMO) transmission employing multiple base station (BS) cooperation...
In this paper, we investigate the impact of channel estimation error on LTE-Advanced (LTE-A) uplink using coordinated multipoint (CoMP) joint reception (JR) in a heterogeneous network (HetNet). The uplink CoMP capacity in bits/sec/Hz/m2 in principle increases in proportional to the number/density of CoMP reception points (RPs). However, the data capacity is limited due to reference signal (RS) capacity...
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