SINR

Seamless handover between different access technologies is a great challenge as it needs to obey different performance of QoS and security constraints. Subscribers are becoming more demanding regarding roaming capabilities across different networking technologies such as WiFi, WiMAX, and CDMA as they claim service continuity with QoS requirement and good security features. In this paper, a QoS based vertical handover mechanism between WiMAX and WiFi networks is proposed by applying the Signal to Interference and Noise Ratio SINR. The Media Independent Handover MIH (IEEE 802.21) protocol is adopted to assist in the handover decisions by providing a suitable platform for vertical handovers. The performance of the proposed SINR based vertical handover algorithm and RSS based vertical handover algorithm have been evaluated in terms of the maximum downlink throughputs.

LTE is an emerging wireless communication technology to provide high-speed data service for the mobile phones and data terminals. To improve indoor coverage and capacity Femtocells are included in 3GPP since Release 8. There is no common simulation platform is available for performance justification of LTE-Femtocells. LTE-Sim is an object-oriented open source simulator which incorporates a complete protocol stack can be used for simulating two-tier macro-femto scenarios. To the best of our knowledge no paper provides the guideline to perform system level simulation of Femtocell networks. Here, in this paper Femtocells performance is evaluated in multi-Macrocells and multi-Femtocells environment with interference from Microcells and Macrocell users along with the scripting. KEYWORDS Channel quality indicator (CQI), Femto Access Point (FAP), Macro eNodeB (MeNB), Macrocell User Equepment (MUE), Moblity Management Entity(MME), Signal to Interference Plus Noise Ratio(SINR), Physical Layer(PHY)

Seamless handover between different access technologies is a great challenge as it needs to obey different performance of QoS and security constraints. Subscribers are becoming more demanding regarding roaming capabilities across different networking technologies such as WiFi, WiMAX, and CDMA as they claim service continuity with QoS requirement and good security features. In this paper, a QoS based vertical handover mechanism between WiMAX and WiFi networks is proposed by applying the Signal to Interference and Noise Ratio SINR. The Media Independent Handover MIH (IEEE 802.21) protocol is adopted to assist in the handover decisions by providing a suitable platform for vertical handovers. The performance of the proposed SINR based vertical handover algorithm and RSS based vertical handover algorithm have been evaluated in terms of the maximum downlink throughputs.

Mobile operators commonly use macro cells with traditional wide beam antennas for wider coverage in the cell, but future capacity demands cannot be achieved by using them only. It is required to achieve maximum practical capacity from macro cells by employing higher order sectorization and by utilizing all possible antenna solutions including smart antennas. This paper presents enhanced tessellation for 6-sector sites and proposes novel layout for 12-sector sites. The main target of this paper is to compare the performance of conventional wide beam antenna, switched beam smart antenna, adaptive beam antenna and different network layouts in terms of offering better received signal quality and user throughput. Splitting macro cell into smaller micro or pico cells can improve the capacity of network, but this paper highlights the importance of higher order sectorization and advance antenna techniques to attain high Signal to Interference plus Noise Ratio (SINR), along with improved network capacity.  Monte Carlo simulations at system level were done for Dual Cell High Speed Downlink Packet Access (DC-HSDPA) technology with multiple (five) users per Transmission Time Interval (TTI) at different Intersite Distance (ISD). The obtained results validate and estimate the gain of using smart antennas and higher order sectorization with proposed network layout.

In this paper we discuss and compare methods to analyse the influence inter-cell interference will have on coverage/outage probabilities in cellular networks. The framework is based on a common method to find the Laplace transform of the distribution of interference from neighbouring cells. It turns out that for Suzuki distributed fading the analysis is highly simplified. In case of Rayleigh faded channels only, the analysis is even more simplified. The modelling approach, which is based on classical probab ility methods, rather than on modern measure theory for point processes, allows for both fixed and stochastic locations of base stations. The different models are applied to quantify the effect of inter-cell interference on coverage/outage probabilities and on spectrum efficiencies in LTE networks. We consider several scenarios ranging from fixed hexagonal layout of base station to stochastic location of based on uniform distribution of base stations. We also extend the coverage/...

This paper aims to show the effect of macrocellular network densification on the capacity, energy and cost efficiency. The presented results are based on radio propagation simulations that consider macrocellular network with different inter-site distances, i.e. different site densities, and also take into account the presence of indoor receiver points by varying outdoor and indoor receiver distribution. It is observed that as a result of densifying the network, the cell spectral efficiency reduces due to increasing level of inter-cell interference. However, as a result of densification, the network area capacity can be improved since the area spectral efficiency increases. Nevertheless, the densification efficiency decreases because of the reduction of cell spectral efficiency, especially when indoor receiver points are taken into account. The results hence indicate that densification of macrocellular network suffers from inefficiency which results in higher energy and cost per bit per Hertz, and thus calls for alternative methods to deploy networks, or alternatively, more sophisticated methods, such as base station coordination or inter-cell interference cancellation techniques, to be implemented for future cellular networks

In this paper a new distributed power control algorithm is proposed. It is based on the minimization of multiple objectives. The objectives are to keep the transmitted power as close to the minimum power as possible and simultaneously, to hold the carrier to interference ratio (CIR) close to the given target. The multi-objective optimization problem is transformed into a single-objective optimization problem. Its solution results in a new, efficient power algorithm, which is simple to implement. Simulations demonstrate that it converges faster than the conventional power control algorithms. Also, the average transmitted power is less than the average transmitted power using the conventional methods with comparable quality of service (QoS). Noisy, dynamical environment is assumed in the simulations. The algorithm has been modified to work with quantized carrier to interference ratio (CIR). A new soft dropping algorithm based on a multi-objective technique has been developed.

Mobile had made the life of today's world easy to communicate anywhere while Mobile terminals allow users to access service while on the move. Mobile terminals have made a rapid development in the mobile network industry in past decade. However as the number of cellular subscriber's increases, the interference that will be experienced by the systems will also increase. This means that many large cellular systems will, sooner or later, have to handle interference problems. In this paper, all handoff effects of mobile Wimax networks are carried out. Performance is evaluated in terms of the expected number of handoffs, the expected handoff delay, standard deviation of handoff location, and the expected link degradation probability as well. The results showed that the threshold and hysteresis margin of the handover should be selected by considering the tradeoffs between the "ping-pang" effect and the extra interference causing to neighbouring cells due to the poor qual...

With the remarkable impact and fast growth of the mobile networks, the mobile base stations have been increased too, especially in the high population areas. These base stations will be overloaded by users, for that reason the small cells (like pico cells) were introduced. However, the intercell interference will be high in this type of Heterogeneous networks. There are many solutions to mitigate this interference like the inter-cell interference coordination (ICIC), and then the further enhanced ICIC (Fe-ICIC) where the almost blank subframes are used to give priority to the (victim users). But it could be a waste of bandwidth due to the unused subframes. For that reason, in this paper, we proposed an adaptive reduced power subframe that reduces its power ratio according to the user’s signal-to-interference-plus-noise ratio (SINR) in order to get a better throughput and to mitigate the intercell interference. When the user is far from the cell, the case will be considered as an edge user and will get a higher priority to be served first. The results show that the throughput of all users in the macro cells and pico cell will be improved when applying the proposed scheme in term of throughput for the users and the cells.

The great increase in user demand to roam among various wired and wireless communications networks without affecting the signal quality has attracted many researchers to investigate about the best handover decision criteria that promote seamless handover. IEEE 802.21 Media Independent Handover (MIH) standard can be considered to be the best environment for handling both horizontal and vertical handover. In this work, we propose a new decision criteria based on MIH signalling among WLAN and WiMAX networks which depend on the received S ignal to Interference and Noise Ratio (S INR) instead of the traditional Received S ignal S trength (RS S) criteria. In order to provide multimedia QoS inside the integrated network environment, the proposed VHD provides the knowledge of the achievable bandwidth from both networks by using the re ceived S INR. S imulation-based outputs along with analytical results have confirmed that our proposal would offer the end user with better performance during the handover stage.

In this paper we discuss and compare methods to analyse the influence inter-cell interference will have on coverage/outage probabilities in cellular networks. The framework is based on a common method to find the Laplace transform of the distribution of interference from neighbouring cells. It turns out that for Suzuki distributed fading the analysis is highly simplified. In case of Rayleigh faded channels only, the analysis is even more simplified. The modelling approach, which is based on classical probability methods, rather than on modern measure theory for point processes, allows for both fixed and stochastic locations of base stations. The different models are applied to quantify the effect of inter-cell interference on coverage/outage probabilities and on spectrum efficiencies in LTE networks. We consider several scenarios ranging from fixed hexagonal layout of base station to stochastic location of based on uniform distribution of base stations. We also extend the coverage/outage analysis for the Ginibre Point Process to Suzuki faded environment. Numerical examples show large differences in both spectrum efficiency and coverage/outage probabilities for the different network scenarios considered.

Abstract—In wireless networks that operate in those bands where spectrum sharing occurs across a variety of wireless technologies, such as the license-free Industrial Scientific and Medical (ISM) bands, mitigating interference becomes challeng-ing. Addressing interference is an important aspect for the design and development of solutions intended to satisfy the demands of applications requiring QoS guarantees. In this paper, we investigate dynamic radio resource adaptation techniques based on instantaneous spectrum usage. Using a novel metric to quantify the spectrum usage, we address packet size and error correc-tion code overhead optimisations. On one hand, large payloads lead to energy and throughput gains due to the amortisation of the transmission overheads, but on the other hand, larger payloads imply larger resource wastage in the event of packet collisions. Using real-world data, we found that payload size in the neighbourhood of 100 bytes leads to near-optimal performance i...

In modern cellular system such as LTE Advanced (LTE-A), frequency reuse scheme is targeted to be applied to fulfill the requirement of high capacity broadband access and high spectrum efficiency. But this kind of frequency planning may lead to the worse inter-cell interference (ICI) level experienced especially by a user located at the cell edge. Soft Frequency Reuse (SFR) is considered as an effective way to mitigate inter-cell interference and maintain capacity. We propose a power division SFR, known as multi level SFR technique to minimize ICI in a designed LTE-A network for suburban environment. Service area of LTE-A network was first developed to deploy particular number of eNB by using LTE network planning tools in the frequency of 1800 MHz with the use of SISO (Single Input Single Output) antennas. Coverage dimensioning and propagation consideration determine LTE-A parameters which were used in the simulation. Monte carlo simulation is executed to examine the performance of SFR for LTE-A downlink transmission to address different power ratio and traffic loads problem. Both performance of cell edge users and overall cell performance are evaluated in terms of CINR, BLER, and throughput. Performance with SFR is also compared with the classical frequency reuse one and three.

We study combinatorial auctions for the secondary spectrum market. In this market, short-term licenses shall be given to wireless nodes for communication in their local neighborhood. In contrast to the primary market, channels can be assigned to multiple bidders, provided that the corresponding devices are well separated such that the interference is sufficiently low. Interference conflicts are described in terms of a conflict graph in which the nodes represent the bidders and the edges represent conflicts such that the feasible allocations for a channel correspond to the independent sets in the conflict graph. In this paper, we suggest a novel LP formulation for combinatorial auctions with conflict graph using a non-standard graph parameter, the so-called inductive independence number. Taking into account this parameter enables us to bypass the well-known lower bound of \Omega(n^{1-\epsilon}) on the approximability of independent set in general graphs with n nodes (bidders). We achieve significantly better approximation results by showing that interference constraints for wireless networks yield conflict graphs with bounded inductive independence number. Our framework covers various established models of wireless communication, e.g., the protocol or the physical model. For the protocol model, we achieve an O(\sqrt{k})-approximation, where k is the number of available channels. For the more realistic physical model, we achieve an O(\sqrt{k} \log^2 n) approximation based on edge-weighted conflict graphs. Combining our approach with the the LP-based framework of Lavi and Swamy, we obtain incentive compatible mechanisms for general bidders with arbitrary valuations on bundles of channels specified in terms of demand oracles.

This paper proposes distributed joint power and admission control algorithms for the management of interference in two-tier femtocell networks, where the newly-deployed femtocell users (FUEs) share the same frequency band with the existing macrocell users (MUEs) using code-division multiple access (CDMA). As the owner of the licensed radio spectrum, the MUEs possess strictly higher access priority over the FUEs; thus, their quality-of-service (QoS) performance, expressed in terms of the prescribed minimum signal-to-interference-plus-noise ratio (SINR), must be maintained at all times. For the lower-tier FUEs, we explicitly consider two different design objectives, namely, throughput-power tradeoff optimization and soft QoS provisioning. With an effective dynamic pricing scheme combined with admission control to indirectly manage the cross-tier interference, the proposed schemes lend themselves to distributed algorithms that mainly require local information to offer maximized net utility of individual users. The approach employed in this work is particularly attractive, especially in view of practical implementation under the limited backhaul network capacity available for femtocells. It is shown that the proposed algorithms robustly support all the prioritized MUEs with guaranteed QoS requirements whenever feasible, while allowing the FUEs to optimally exploit the remaining network capacity. The convergence of the developed solutions is rigorously analyzed, and extensive numerical results are presented to illustrate their potential advantages.

Array based beamforming is an intensively used method for signal of interest (SOI) reception. To maximize the signal to interferers plus noise power ratio (SINR), the steering vector of the SOI must be known. A well studied approach for beamforming in the presence of steering vector uncertainty is to minimize array power while constraining the response to all steering vectors within the uncertainty set. Since such an approach is not directly related to SINR optimization, in this work we suggest to calculate beamformer weights that maximize the SINR for the worst case steering vector within an ellipsoidal set.

Multiple Input and Multiple Output (MIMO) is one of the techniques used tiimprove the system performance. In this thesis, we improve and evaluate the system performance of MIMO deploying MRT technique at the transmitter and MRCtechnique at the receiver with an assuming that the system can obtain perfect CSI.We derived expressions for outage probability and symbol error rate and simulationgraphs for SISO, SIMO, MISO, and MIMO in terms of outage probability. Our results show that the MIMO system performance is better than other configurations.We also observed that SISO have the least performance where SIMO and MISOhave same performance. The performance also increases as the number of antennasincrease in the system and it is suggested to use MIMO when performance is givehigh priority than cost

Abstract—In this paper, we study a coordinated beamforming (CBF) scheme for a multi-cell scenario where precoding/beamforming vectors for all coordinating base stations (BSs) are jointly designed in a manner that each BS transmits to its local users. We minimise the ...

In this paper we study the topological properties of wireless communication maps and their usability in algorithmic design. We consider the SINR model, which compares the received power of a signal at a receiver against the sum of strengths of other interfering signals plus background noise. To describe the behavior of a multi-station network, we use the convenient representation of

In order to fulfil the increasing demands on capacity and coverage of mobile communication systems smart or intelligent antennas have been suggested. These antennas increase the spectral efficiency of a wireless system by using arrays of antenna elements to shape RF signals in particular directions. Generally, smart antennas can be divided into two approaches: switched multi-beam and adaptive. Adaptive antennas