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In multi-tier cellular/small cell networks, user performance is largely affected by the varying transmit powers, distances, and non- uniform traffic loads of different BSs in both the downlink (DL) and uplink (UL) directions of transmission. To optimize user performance in such networks, decoupled UL-DL association (DUDe) has recently been investigated. DUDe enables a user to be associated with different...
Recent studies have revealed that due to the increasing number of wireless users, spectrum scarcity problem has arisen. In order to alleviate this problem, cognitive radio technology has emerged with the aim of using available spectrum in an opportunistic manner by secondary users. While utilizing licensed spectrum, it is inevitable for secondary users not to cause any interference to the primary...
Public safety networks are desired to meet increasing demands for sharing images or videos among first responders and incident commanders. Long term evolution (LTE) is considered a candidate to achieve such broadband services. Base stations (BSs) of public safety LTE will probably be deployed less densely than those of commercial LTE to enable lower capital expenditures related to BS deployment. Although...
Cooperative spectrum sensing is an efficient way to improve the spectrum utilization in cognitive radio networks (CRNs), while the system performance of such CRNs is often degraded due to the spectrum sensing data falsification (SSDF) attack launched by malicious secondary users (SUs). Traditional static threshold-based decision strategy in the fusion center (FC) can be effective to defend against...
In this paper, we consider amplify-and-forward cognitive relay networks in a spectrum-sharing environment. We present the performance analysis under two different partial relay selection (PRS) schemes, namely source-relay partial relay selection (SR-PRS) and relay-destination partial relay selection (RD-PRS). Specifically, we consider interference power constraint on secondary source and relay nodes,...
Device-to-device (D2D) communications have the potential to improve spectrum efficiency and link capacity by allowing nearby devices to communicate directly with each other on the licensed frequency resource. However, the co-channel interference (CCI) among D2D pairs is the major issue that needs to be solved when they are sharing the same frequency resource. The interference alignment (IA) is an...
Orthogonal frequency division multiple access (OFDMA) is an effective method to reduce inter symbol interference in LTE systems. Doppler shift, however, leads to a loss of sub-channel orthogonality, resulting in inter-channel interference in high speed environment. Firstly, this paper develops the mathematical formulae describing the interference on resource block (RB) which is the smallest resource...
Recently, interference problem between WiFi devices is serious by thoughtlessly installation of access points (APs). To solve this problem, we suggest interference alignment (IA) algorithm and analyze the link level performance of IA in IEEE 802.11ac specification.
In this paper, we propose a non-cooperative, dynamic and extensive game model for routing in a wireless sensor network (WSN). We treat each sensor node as a player who has a strategy to choose from in order to find the route that meets certain objective functions. A multi-hop routing is performed concurrently between multiple source and multiple destination nodes considering signal-to-noise-interference...
In order to estimate the DL cell average throughput of LTE network, the paper proposes an algorithm of LTE throughput based on MCS level distribution which can be used to estimate the DL cell capacity under different load conditions. The algorithm is convenient for operation and useful in guiding network planning and optimization, the simulation results show that the algorithm is effective and the...
Licensed Assisted Access (LAA) represents a new paradigm for LTE, where unlicensed bands are used in conjunction with licensed bands to increase network capacity. The main challenge of LAA is ensuring that unlicensed bands are shared with WiFi systems in an efficient manner. In this paper, we study a coexistence solution based on channel selection. A centralized channel selection mechanism which increases...
In this paper, three schemes based on the proportional fairness scheduling with power control are proposed for the virtual full-duplex (VFD) scheme by jointly considering the downlink (DL) and uplink (UL) UE pair selection and UL power control. In particular, the optimal scheme is derived via the exhaustive search for the UE pair and UL power. The second scheme reduces the complexity of the UE pair...
Complementing macro-only cellular networks with low-powered base stations is a promising deployment solution to cope with exploding data traffic in the coming years. In Long Term Evolution (LTE)-Advanced, interference mitigation technologies, like the linear interference rejection combining (IRC) receiver and Enhanced Inter-Cell Interference Coordination (eICIC), are introduced to address the co-channel...
In this paper, we propose a new method of secrecy signal and artificial noise (AN) transmission for a MISO wiretap channel in wireless cellular networks. We first design the secrecy signal beamformer such that its power leakage to the unintended directions is minimized, then we concentrate the AN on the directions with higher risk of information leakage, rather than broadcast it isotropically, such...
In this paper, a low overhead preamble structure is proposed for the interference approximation method — complex (IAM-C) method in offset quadrature amplitude modulation based orthogonal frequency division multiplexing (OQAM-OFDM) systems. Compared with the conventional preamble structure with three columns of symbols, the proposed preamble structure only requires two columns of symbols as the preamble...
In this paper, we evaluate the interference effect of LPR on BSDS in 24.05–24.25 GHz band. The geographical model for the analysis is used and the dynamic simulation is performed, taking into account real environment. The results show that the received interfered power from LPR depends on the separate distance along the road and relative position. It is, also, realized that an appropriate location...
This article investigates the problem of efficient distributed dynamic spectrum access in self-organizing networks with goe-location database, using a game theoretic approach. In particular, we propose a novel utility function, which aims to complete the data transmission of users and improve the satisfactory level of network by considering the efficient use of TV White-space Spectrum (TVWS) resource...
To support the unrelenting demand of services with gigabit data rates in indoor scenarios, a dense heterogeneous small cell network (HSCN) is presented as a promising paradigm for the fifth generation system. In this paper, the coverage probability for the downlink HSCN with three cell association methods, namely the nearest association, the N-th nearest association and the maximum received power...
To achieve higher spectral efficiency in future wireless networks, small cells have been conceived to be deployed over conventional macrocell networks, generating heterogeneous networks (HetNets). However, interference between different tiers of HetNets is the main bottleneck for high spectral efficiency. Spectrum access, including spectrum deployment and channel access, is one of the most powerful...
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