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.
The standardization for the fifth generation (5G) of mobile and wireless networks is at its early phase and has recently completed the first study item in Release 14. Nevertheless, there is a consensus that 5G will address the diverse service requirements of high-variety use cases. The network shall cope with such variation effectively and cost-efficiently even though the requirements can change over...
The existing cellular networks are being modified under the umbrella of fifth generation (5G) networks to provide high data rates with optimum coverage. Current cellular systems operating in ultra high frequency (UHF) bands suffer from severe bandwidth congestion hence 5G enabling technologies such as millimeter wave (mmWave) networks focus on significantly higher data rates. In this paper, we explore...
In this paper, a multi-cell joint optimization scheme based on pilot allocation is proposed in order to mitigate pilot contamination for multi- cell massive MIMO systems. This method measures interference of each pilot sequence caused by users multiplexing from adjacent cells exploiting the massive MIMO characteristics of fading channels. The scheme takes jointly optimizing a plurality of cells into...
We study the physical-layer performance of a wideband multihop system in which a long chain of amplify-and-forward relays is used for routing orthogonal frequency division multiplexing (OFDM) symbols from a source to a destination. Especially, the symbols are modulated in the source and demodulated in the destination while the relays simply forward respective waveforms with scalar amplification. We...
In this paper, the outage performance of hybrid automatic repeat request (hybrid-ARQ) over a full- duplex decode-and-forward relay network is analyzed. Nakagami-m distribution is assumed for fading channels such that the analysis results can be easily extended to other fading distributions. Compared to the conventional half-duplex relay mode, full-duplex relay network enables the relay nodes to receive...
In database-driven spectrum sharing, despite the spectrum sharing policy given by a database, harmful interference can occur between a primary user (PU) and a secondary user (SU) due to the unexpected propagation paths. In a previous study, a primary exclusive region (PER) centered at a PU, wherein the SUs are forbidden to use the spectrum, has been proposed. However, the PER figure that efficiently...
Massive Multiple-input Multiple-output (MIMO) adaption is one of the primary evolving objectives for the next generation high speed train (HST) communication system. In this paper, we consider how to design an efficient low-complexity location-aware beamforming for the multi-user (MU) massive MIMO system in HST scenario. We first put forward a lowcomplexity beamforming based on location information,...
Future mobile networks are converging toward heterogeneous multi-tier networks, where various classes of base stations (BS) are deployed based on user demand. So it is quite necessary to utilize the BSs resources rationally when BSs are sufficient. In this paper, we develop a more realistic model that fully considering the inter-tier dependence and the dependence between users and BSs, where the macro...
In random machine-to-machine (M2M) networks, the network topology along with the variation of the wireless channel are the main sources of uncertainty that affect the network performance. Unlike most prior works, which assume a reference receiver such as aggregator located at a certain fixed point, this paper discusses a more general case where the intended receiving node can be any randomly-located...
In this paper, we investigate the sum-rate maximization in the Device-to-Device (D2D) communication underlaying cellular networks, where many cellular users (CUs) share the uplink resource with the D2D pairs. We show that the system sum- rate maximization problem can be formulated as a mixed integer non-linear programming problem, which is NP-hard in general. We circumvent this difficulty by applying...
This paper investigates an underlay cognitive radio (CR) that extracts energy from radio-frequency signals of one primary user. We assume that both the wireless energy harvesting and the secondary transmission processes of the CR suffer Rayleigh block fading. Considering the intrinsic harvesting- transmitting tradeoff, we optimize the harvesting time and transmit power of the CR to minimize the outage...
We propose a new cellular network model that captures both strong repulsion and randomness between base stations. The base stations are modeled by superposition of a random shifted grid with intensity λg for the grid base stations and an independent Poisson point process with intensity λρ for the random base stations. Assuming that the typical user is associated with the base station that provides...
In an ultra-dense network (UDN) where there are more base stations (BSs) than active users, it is possible that many BSs are instantaneously left idle. Thus, how to utilize these dormant BSs by means of cooperative transmission is an interesting question. In this paper, we investigate the performance of a UDN with two types of cooperation schemes: non-coherent joint transmission (JT) without channel...
This paper proposes a novel anti-eavesdropping scheme by introducing artificial noise caused by friendly jammers deployed in wireless networks. In particular, we propose an analytical model to quantify the eavesdropping risk of wireless network with friendly jammers. Our approach considers both large-scale path loss and Rayleigh fading. Our numerical results show that the eavesdropping risk of wireless...
Recently, a new paradigm of multiple access (MAC) along with one eavesdropper to achieve secrecy transmissions has been getting in focus. However, all existing work on such multiple access wiretap channel (MAC-WT) mainly concentrates on the secrecy performance of the system as a whole from an information theoretic perspective. In this work, we investigate the secrecy performance of a single transmitter...
Effective capacity analysis is a powerful tool to investigate the impact of physical layer designs on the link layer delay-sensitive QoS performance, which is important for real-time multimedia applications. In this paper, we rigorously analyze the effective capacities of downlink large-scale antenna systems. The main focus is to establish the fundamental effective capacity in a very-large MIMO system,...
We study the optimum designs of a wireless ad hoc network that employs a random multiple access protocol and operates in an interference-limited environment. The nodes are assumed to form a homogeneous Poisson point process (PPP). With the random multiple access protocol, each node transmits with a certain probability, the value of which is critical to system performance. A higher transmission probability...
Network coding-based caching at base stations (BSs) is a promising caching approach to support massive content delivery over wireless networks. However, existing network coding-based caching designs do not fully explore and exploit the potential advantages. In this paper, we consider the analysis and optimization of a random linear network coding-based caching design in large-scale successive interference...
A novel adaptive transmission scheme for discrete Fourier transform modulated filter bank based transceivers for underlay cognitive radio is proposed aiming to minimize the secondary user average bit-error rate (BER) for bit-interleaved coded modulation subject to a stochastic chance-based interference constraint. For a given confidence level, exact expressions for the BER are derived based on assumed...
This paper optimizes the pilot assignment and pilot transmit powers to mitigate pilot contamination in Massive MIMO (multiple-input multiple-output) systems. While prior works have treated pilot assignment as a combinatorial problem, we achieve a more tractable problem formulation by directly optimizing the pilot sequences. To this end, we compute a lower bound on the uplink (UL) spectral efficiency...
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.