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For meteor burst communications (MBC), although per- survivor processing (PSP) based on joint data and channel estimation provides superior performance and robustness for meteor burst communications (MBC), great computational complexity constrains its application in practice. On this occasion, a dimension-down PSP (D- PSP) algorithm and a adaptive state reduction of PSP (ASRP) algorithm are proposed...
Access Point (AP) selection is important in WLANs as it affects the throughput of the joining station (STA). In this paper, we propose a class of AP selection algorithms to maximize the joining STA's expected throughput by considering interference at STAs, and transmit opportunities (TXOPs) at APs. Specifically, we collect a binary-valued local channel occupancy signal, called busy-idle (BI) signal,...
Under the high mobility scenario, some factors have a strong influence on LTE system performance such as the velocity of mobile user, pilot patterns, multiple-input-multiple-output (MIMO) transmission strategies, wireless channel characteristics, etc. The doppler shift or spread due to the user velocity will not only cause the inter-carrier-interference (ICI) for orthogonal frequency division multiplexing...
We investigate the influence of channel estimation error on the achievable system-level throughput performance of our previous non-orthogonal multiple access (NOMA) scheme in a multiple-input multiple-output (MIMO) downlink. The NOMA scheme employs intra-beam superposition coding of a multiuser signal at the transmitter and spatial filtering of inter-beam interference followed by an intra-beam successive...
In multichannel cognitive radio networks (CRN), the sequence of sensing order is essential to determine the efficiency of detecting an idle channel and the effective time for spectrum access. Current works on the optimal channel sensing order have to know priori knowledge such as the channel idle probabilities, channel gains and achievable rates of different channels, which dynamically evolve and...
This paper presents a strategy to choose WiFi channels in urban areas. We consider (i) inter-channel interference where adjacent channels interfere with each other in WiFi systems and (ii) urban situations where many APs in different systems are deployed in an uncoordinated way. As it is often hard to identify the channel with less interference in such a situation, we present a channel scoring function...
It is an important issue to design wireless communication and networking that radio resources should be efficiently utilized while providing guaranteed Quality of Service (QoS). In this area, link adaptation based on accurate channel quality estimation has attracted a lot of attention from both academia and industry. Topics such as power control, adaptive modulation and adaptive rate coding are under...
In this paper, we consider a full duplexing (FD) wireless cellular network where a central base station (BS) works in the FD mode while the downlink (DL) and uplink (UL) users work in the time division duplexing (TDD) mode. Since this FD system induces the inter-user interference from UL user to DL user, the main challenge for maximizing the system performances is user pairing that makes a pair of...
Recently, with the concept of blind rendezvous, numerous channel-hopping sequence (CHS) based rendezvous schemes have been proposed to solve the rendezvous problem for neighbor discovery in distributed cognitive radio networks (CRNs). However, the related rendezvous problem for data exchange is not paid the due attention. In this paper, on the basis of existing CHS based rendezvous schemes, we investigate...
Recently, amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay transmissions are studied to achieve high quality communications. On the other hand, they have to estimate all channels between the source-relay and relay-destination nodes in the receiver. In MIMO orthogonal frequency division multiplexing (OFDM) systems, high time resolution carrier interferometry (HTRCI) has been proposed...
Base station cooperation has been shown to significantly mitigate the interference perceived in cellular networks and improve the quality of user experience. On the uplink, joint processing (JP) across antennas within a cluster of base stations yields significant gain, but requires significant backhaul to transport complex I & Q signals. The Network Interference Cancellation Engine (NICE) can...
This paper brings to light the reasoning and principles shaping the standardization direction in the 3rd Generation Partnership Project (3GPP) regarding provision of low complexity Machine Type Communication (MTC), via Long Term Evolution (LTE) of 3GPP. It elaborates 3GPP's approaches and suggestions towards addressing the physical layer challenges and discusses solutions 3GPP proposed specifically...
A distributed antenna system, where antennas at a base station are spatially distributed over the cell, can improve throughput at the cell edge compared to a centralized antenna system. However, the peak capacity degrades when a remote antenna unit has a few antenna elements due to rank deficiency. In general, the number of antennas at the base station is limited by the number of pilot sequences....
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...
The objective of this study is to analyze a new disruptive deployment of wireless sensors in order to cope with the explosive demand for bandwidth while taking into account energy consumption considerations. The work is grounded on the idea of massive network densification by drastically increasing the number of sensors in a given area in a Time Division Duplex (TDD) mode. Using ideas from the recent...
Interference coordination is a critical enabler of heterogeneous networks. In this paper we present a scheduling cooperation scheme that coordinates the resource allocation and user assignment across layers. The proposed scheme focuses on mitigating the interference generated by macro-associated users in the proximity of small cells by exchanging the information of user assignment on the severely-interfered...
The resource allocation problem has been a very hot topic since the migration from CDMA to OFDMA modulation schemes has taken place for the wireless communication systems. The scheduling problem has transformed into a rather more complex one due to the increased number of resource elements at hand. There have been numerous proposed scheduling algorithms with various analytical approaches to enhance...
Over-the-top estimation of available bandwidth (AB) in a network path has been well studied for wired networks. The AB of a path denotes its slack capacity, i.e., the bandwidth available for use in the path without impacting the existing traffic. This estimation problem has been receiving attention only recently in cellular networks, which are increasingly becoming one of the main modes of access...
In this paper, we present a novel signal processing unit built upon the theory of factor graphs, which is able to address a wide range of signal processing algorithms. More specifically, the demonstrated factor graph processor (FGP) is tailored to Gaussian message passing algorithms. We show how to use a highly configurable systolic array to solve the message update equations of nodes in a factor...
This paper investigates the throughput performance using adaptive modulation and coding (AMC) focusing on the causes of impairment to Orthogonal Frequency Division Multiplexing (OFDM) - Multiple-Input Multiple-Output (MIMO) multiplexing. We first investigate the influence of a limited number of modulation and coding schemes (MCSs) and channel estimation error for MCS selection based on mutual information...
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