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.
We consider training-based channel estimation for cloud radio access networks (CRANs), in which a large amount of remote radio heads (RRHs) and users are randomly scattered over a certain service area. In this model, assigning orthogonal training sequences to all users, if possible, will cause a substantial overhead to the overall network. Instead, we introduce the notion of local orthogonality, in...
Massive multiple-input multiple-output (MIMO) is one of the promising technologies to be used in the future fifth generation (5G) wireless networks for its capability to increase the system throughput, improve spectral efficiency and energy efficiency. To achieve these benefits of the massive MIMO, there are many challenges that need to be handled. One of these challenges is the pilot contamination...
A barrage relay network (BRN) is a broadcast-oriented ad hoc network involving autonomous cooperative communication, a slotted time-division frame format, and a coarse slot-level synchronization. While inherently a broadcast protocol, BRNs can support unicast transmission by superimposing a plurality of controlled barrage regions (CBRs) onto the network. Within each CBRs, a new packet is injected...
Adaptive code modulation (ACM) has been studied for last two decades to enhance the bandwidth and power efficiency in a bandwidth-constrained and power-constrained communication system environment. This paper studies how to decide the boundaries of a signal-to-noise ratio (SNR) for the ACM mode selection for a given set of parameters and system model. Also, this paper proposes an efficient and practical...
In this paper, we consider an underlay cognitive radio (CR) multicast network where secondary users (SUs) coexist with primary users (PUs). The cognitive radio network (CRN) consists of a cognitive base station (CBS) and multiple multicast groups. Each multicast group comprises of a number of SUs and is served by the CBS using a common PU channel. Our objective is to minimize the aggregate group outage...
This paper considers the performance of the return link for the hybrid satellite terrestrial communication systems (HSTCSs) under the terrestrial interference. The hybrid beam models are proposed by considering the equivalent inter-beam interference factor α from adjacent beams and the intra-beam equivalent interference factor β from the terrestrial communication systems (TCSs). We set up the channel...
This paper considers distributed massive MIMO networks where a large number of antennas, either collocated or geographically scattered over a region, communicate with mobile users. This communication is impaired by interference from similar transmissions in adjacent regions and by noise. Focusing on zero-forcing (ZF) reception, we derive simple expressions that very accurately approximate the instantaneous...
Cell-Free Massive MIMO comprises a large number of distributed single-antenna access points (APs) serving a much smaller number of users. There is no partitioning into cells and each user is served by all APs. In this paper, the uplink performance of cell-free systems with minimum mean squared error (MMSE) and large scale fading decoding (LSFD) receivers is investigated. The main idea of LSFD receiver...
In this paper, we analyse the performance of multi-beam satellite communication where each beam is paired with a single user. We consider terrestrial interference from cellular base stations (BSs) also communicating with the users in the system. BS locations are modelled as an homogeneous Poisson point process. We employ stochastic geometry tools to characterise the terrestrial interference and also...
In this paper, the power allocation in cognitive radio networks is studied by considering the power amplifier non linearity causing adjacent channel interference to the primary receivers and disturbing the received signal to noise ratio in the secondary receivers. Dynamic range of the power amplifier is assumed to be limited. Throughput is derived for probability of data transmission between the secondary...
System capacity in LTE network becomes a more important factor in that voice call is changing from circuit switching to packet switching. In particular, quality improvement in uplink is far more challenging than downlink due to transmit power restriction in UE and fractional inter-cell interference. A novel frequency selective scheduling algorithm for uplink capacity enhancement is proposed and its...
Energy harvesting relaying is a promising solution to the extra energy requirement at the relay. In this paper, the outage probability of two-way amplify-and-forward relaying system using energy harvesting techniques is proposed. The analysis takes into account both the Nakagami-m fading caused by signal propagation and the interference at relay caused by other transmitters. The relay harvests energy...
Small cell deployments are one of the most significant long-term strategic policies of the mobile network operators since small cell architecture delivers not only the required capacity boost but also the flexibility important for immensely-localized deployments in high-traffic environments. In HetNets, small cells serve as offloading spots in the radio access network to offload users and their associated...
A Frequency Reuse algorithm which divides the users into two groups called Cell-Center Users (CCUs) and Cell-Edge Users (CEUs) is one of the most effective techniques that can mitigate the InterCell Interference as well as improve the spectrum efficiency in cellular networks. In literature, most of work on Strict Frequency Reuse algorithms in a Spatial Point Poisson network assumed that the reuse...
In this paper, we study the reliability-security tradeoff for a secondary network in an underday cognitive radio (CR) environment. In the proposed protocol, a secondary transmitter (ST) transmits its data to a secondary receiver (SR) in presence of a secondary eavesdropper (SE) that tries to overhear the ST data. Moreover, a secondary jammer (SJ) that harvests energy from the radio frequency (RF)...
Pilot contamination caused by non-orthogonal pilot sequences reuse in adjacent cells has become one of the main impairments for massive multiple-input multiple-output (MIMO) systems. A scheme named flexible pilot reuse is proposed in this paper to reduce the effect. The main idea is that users suffered from mild pilot contamination (PC) are allocated the same set of orthogonal pilots, while the users...
In wireless networks, interference modeling is essential for performance analysis and protocol design, since it is the most important cause of performance degradation. The interferers are usually assumed to be random and their locations modeled by a homogeneous Poisson point process (PPP). Performance analysis in wireless networks with Poisson field of interferers is mainly based on the characteristic...
In this paper, we consider two base stations (BSs) which maximize the achievable rate for two users connecting to each BS and sharing channel state information (CSI) in a multi-cell processing (MCP) framework. We propose a two way channel estimation or prediction process. Such framework has promising outcomes in terms of feedback reduction and achievable rates moving the system from one with unknown...
Social relations between users is a key factor impacting the willingness of users to participate in D2D delivery. However, close social ties and proximity location of users can not always be satisfied due to the time and space limits. In this paper, we introduce social credit to stimulate selfish users for an active D2D communication networks, which is a global and wide social feature measure. Queuing...
Green cognitive radio has attracted significant research attention as an effective means of alleviating spectrum scarcity and energy-saving problem in wireless communications. In this paper, we focus on the power allocation for maximizing the transmission throughput and energy efficiency (EE) of secondary users (SUs). More specifically, we propose a multi-band power allocation scheme, where multiple...
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.