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In a short-range multiple-input and multiple-output (SR-MIMO) transmission system that relies on line-of-sight (LOS) propagation, the channel matrix is determined by the antenna geometry, hence radio frequency (RF) signal processing by using an analog matrix circuit is a valid means of separating spatially-multiplexed multiple signal streams. To date several simple decoding methods utilizing this...
Indoor localization has received significant attention over the last decade. For WLANs, Received Signal Strength (RSS) based techniques have been the most popular due to the simplicity of measuring the power and the ubiquity of WiFi infrastructure and devices in different indoor environments. Recently, Time-of-arrival (TOA) techniques has been proposed to be incorporated into IEEE 802.11 standards...
A key issue impacting the transmit to receive (TX-RX) isolation in Electrical Balance (EB) Duplexers is dynamic matching of the antenna impedance by the balancing network. Circuit simulations including embedded antenna measurements have been used to investigate the variation in TX-RX isolation due to interaction with the user and the local environment. Simulated results at 847MHz and 1960MHz show...
A non-orthogonal waveform transmission (NOWT) technique with convolutional multiplexing signalling (CMS) is introduced and analyzed, which can improve the data rate and spectrum efficiency of the wireless communication system. By narrowing the time interval of pulse shaping filter and overlapping parallel data branches together, the technique can obtain preferable gains compared with Nyquist signalling...
Device-to-device (D2D) connectivity is likely to represent a major enabling technology for future fifth generation (5G) radio access networks. In this paper, we introduce a new model for device cooperation in 5G radio access networks termed frequency-selective soft forwarding (FSSF). FSSF is based on soft-combining by a target user equipment (TUE) of selectively forwarded soft information data by...
This paper presents a unique probing scheme and a rate adjustment algorithm that can be used for estimating the available bandwidth (ABW) of an end-to-end network path more accurately and non-intrusively. The proposed algorithm is based on the well-known concept of self-induced congestion and it features a unique probing train structure in which there is a region where packets are sampled more frequently...
In this paper, we study a multiuser indoor Terahertz (THz) communication system with antenna array. To capture the distance-frequency dependent peculiarities of THz channels, we design a distance-aware multi-carrier transmission scheme with hybrid beamforming and antenna subarray selection. Specifically, a low complexity greedy subarray selection algorithm is proposed. Simulation results are provided...
In this paper we consider a decode-and-forward cooperative network, which is active in the same bandwidth as a primary user network. The cooperative or secondary user network applies a dynamic resource allocation algorithm to maximize its own performance while limiting the interference caused at the primary user receivers. The main contribution of this paper is the proposition of a new accurate approximation...
A noise-based frequency offset modulation (N-FOM) system is considered, employing a wideband noise carrier, transmit reference modulation and a self-correlation receiver. The performance of such a system in the presence of in-band interference is studied by modeling the interference as a Gaussian random bandpass process and deriving a closed-form expression for the bit error rate (BER). A numerical...
The use of previously unused spectrum in the millimeter-wave band is discussed for future fifth generation (5G) mobile communications systems. The legacy frequency bands are very densely used and free spaces are rare, but the question remains, whether increasing the carrier frequency is a good idea. In this paper we derive frequency dependent link capacities and energy efficiency measures for a small...
In this paper, we propose a cognitive protocol that involves cooperation between the primary and secondary users. In addition to its own queue, the secondary user (SU) has a queue to store, and then relay, the undelivered primary packets. When the primary queue is nonempty, the SU remains idle and attempts to decode the primary packet. When the primary queue is empty, the SU splits the total channel...
The first giga-bit class wireless local area network (wireless LAN) below 6 GHz frequency (the IEEE 802.11ac standard) is attracting attention due to its capability of handling much more of the rapidly growing data traffic. The increased density of wireless LAN access points (APs), however, has induced inter-cell interference that severely degrades system performance. This problem seems to be getting...
To encourage traffic offloading from the Macrocell to its overlaid Picocells in a Heterogeneous Network (HetNet), Cell Range Expansion (CRE) has been widely envisioned, enabling more Macro users to be offloaded to the less saturated Picocells, and enhancing the throughput performance of the entire system. By doing so, users in the Picocell expanded area may experience high interference from the Macrocell...
We consider a distributed detection problem in a large, single-hop, wireless sensor network. Because of limited collection time and bandwidth, the fusion center (FC) is not able to collect the local observations from all sensor nodes. A distributed detection scheme with a selection strategy and a capability to operate in a finite bandwidth is required. We propose an ordered sequential detection scheme...
For the TV white space (TVWS) in a wireless regional area network (WRAN), wireless microphone (WM) signals must be detected as primary users. Since the very narrow band of a WM signal, there will be several spectrum fragments after spectrum sensing. In our work, a singular value decomposition (SVD) based approach is presented to detect multiple WM signals and then to select component carriers (CCs)...
This paper studies spectrum trading in cognitive radio networks in which multiple service providers (SPs) sell unused spectrum to multiple unlicensed secondary users (SUs). Motivated by the nature of the problem with new considerations, spectrum trading is modeled as a multi-leader multi-follower expected Stackelberg game with two levels of competition. The SPs as leaders compete in offering subscription...
In this paper, we propose an auction-based routing algorithm in a distributed cognitive radio network. The routing of packets is viewed as a market-based phenomenon where channels are traded between transmitters and receivers. Message routes are determined through a series of auctions between message senders and forwarders. The use of auction facilitates the determination of the cost of bandwidth...
Radio frequency spectrum within 3–300 GHz has been investigated for the next generation of mobile broadband system. The mmWave mobile broadband (MMB) system is expected to achieve high capacity by utilizing immense bandwidth. However, high attenuation property of mmWave generates outage zone where the signal does not reach frequently in MMB system. To cover outage zone, relay operation has been suggested...
In this paper, a novel multi-carrier and multi-antenna for a multi-tier cellular network is presented for Long-Term Evolution Advanced (LTE-A) heterogeneous networks (Het-Nets) with carrier aggregation enhancement. First, we investigate a system model of frequency domain load balancing-based inter-cell interference coordination (ICIC) to minimize the total interference, while satisfying the required...
In the recent years, a significant research effort has been devoted to the development of bandwidth estimation techniques and tools due to the broad range of possible applications. The vast majority of bandwidth estimation algorithms are designed and optimized for wired networks. Therefore, these solutions not only provide inaccurate results in wireless environments but also rely on some information...
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