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In recent years, there has been an increasing awareness to traffic localization techniques driven by the emergence of heterogeneous networks (HetNet) with small cells deployment and the green networks. The localization of hotspot data traffic with a very high accuracy is indeed of great interest to know where the small cells should be deployed and how can be managed for sleep mode concept. In this...
Lattice reduction (LR) is a powerful technique for improving the performance of linear MIMO detection methods. The efficient LR algorithms can largely improve the performance of the linear detectors (LDs). However, there are two problems involved in the LR-aided detection algorithms. One is that, the reduced basis is still not orthogonal, and most existing LR-aided algorithms devote to find a near...
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...
Recently, a proactive estimation method has been proposed to obtain the cross-channel gain from cognitive transmitter (CT) to primary receiver (PR), where CT acts as a full-duplex amplified-and-forward (AF) relay for primary users. However, since the cognitive and primary users usually have no cooperation, it has no guarantee that the direct and relay signals are synchronized, i.e., the time delay...
In this paper we study the problem of distributed estimation of a random vector in wireless sensor networks (WSN) with linear observation model. Each sensor makes a noisy observation, quantizes its observation, maps it to a digitally modulated symbol, and transmits the symbol over erroneous wireless channels (subject to fading and noise) to a fusion center (FC), which is tasked with fusing the received...
Effective frequency spectrum utilization techniques are required to cope with wireless broadband traffic growth. We are studying a method to minimize mutual radio wave interference by coordinating wireless home network access points (APs). For controlling the radio wave reaching range to reduce interference to neighboring terminals or APs, precisely estimation techniques of range is important. A commonly...
With the increasing demand of wireless applications, current radio transceivers are challenged by the requirement of high data rate and high flexibility. Full-Duplex Dual-Band OFDM radio transceiver is a very promising radio technique to approach this goal. However, the mutual undesirable signal leakages due to the I/Q imbalance in the Full-Duplex Dual-Band RF front-end lead to a significant performance...
We consider a system where multiple users are connected to a small cell base station enhanced with computational capabilities. Instead of doing the computation locally at the handset, the users offload the computation of full applications or pieces of code to the small cell base station. In this scenario, this paper provides a strategy to allocate the uplink, downlink, and remote computational resources...
This paper proposes a model for the management of virtual radio resources. The virtualisation of radio resources is based on aggregating and managing all the available physical radio resources in a set of infrastructures. In this approach, Virtual Network Operators (VNOs) use wireless connectivity in the form of capacity per service, and do not have to deal with physical radio resources at all. Due...
A better understanding of the spatial structure of existing opportunistic wireless network deployments will offer new insights for future deployments, e.g. dense femtocell networks. In this paper we present a performance analysis for three different localization algorithms that support such efforts by finding the location of IEEE 802.11 Wi-Fi access points (APs) from distributed signal strength measurements...
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...
Traffic shifting is an efficient load balancing method to offload traffic from a hot-spot cell to neighbouring cells. This paper proposes a channel-aware optimised traffic shifting (COTS) scheme in LTE-Advanced relay networks. The COTS scheme employs a channel-aware assistant cell selection mechanism, which considers users' channel condition, received from the relay station (RS) in neighbouring cells,...
Automatic detection of cells which are in outage has been identified as one of the key use cases for Self Organizing Networks (SON) for emerging and future generations of cellular systems. A special case of cell outage, referred to as Sleeping Cell (SC) remains particularly challenging to detect in state of the art SON because in this case cell goes into outage or may perform poorly without triggering...
This paper proposes interference suppression schemes by linear combining for wireless multiuser relay communications. Interference from base stations and relays in neighboring cells degrades bit error rate (BER) performance of mobile stations (MSs) near cell boundaries. To suppress such interference for half-duplex relay systems, the proposed methods linearly combine received signals of the first...
In this paper, the mobile deployment and subchannel number distribution are estimated for different values of Anisotropy Ratio (AR) and Mean Building Block Area (MBBA) pairs. This work proposes to model city maps with a particular family of random tessellations: Crack STIT tessellation to generate realistic city maps with a reduced number of parameters: i.e., AR and MBBA. The model is used to compute...
Superposed multicarrier transmission scheme is known to improve frequency utilization efficiency when several wireless systems share the same spectrum. To suppress the effect of interference, forward error correction (FEC) metric masking is proposed. In the technique, log-likelihood ratio (LLR) that corresponds to superposed band is set to zero, because received bits that correspond to superposed...
To improve energy efficiency in low power short-range communication systems such as Wireless Sensor Networks (WSNs) and Wireless Body Area Networks (WBANs), adaptive techniques have been proposed to adjust the transmit waveforms according to the channel conditions. The estimation of channel quality, such as Signal-to-Noise Ratio (SNR), plays an important role in the waveform switching. Errors introduced...
In this paper, we propose a homography-aware semi-supervised formulation for the logo-based indoor localization problem using smartphone cameras. Our method labels unmatched feature points detected inside the logo parts of query images with their estimated 3D coordinates. The 3D coordinates are computed using the homography estimated from the matched features. We demonstrate the accuracy improvement...
In recent years, wireless positioning technologies have been widely considered in the developments of new telecom systems and services. The increasing requirements of location-based services (LBS) in many practical applications have promoted the investigations of location estimation methods. With the system models and network structures addressed in the technical reports of 3GPP, the geometry-improved...
Due to the popularity of location-based services in environment with weak GPS signals, indoor location estimation problem have attracted more and more attention in recent years. Among several distance-related measurements, channel impulse response (CIR) reflects multi-path situation between the transmitter and receiver pair and is suitable to describe the characteristic of different positions. Note...
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