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This paper presents an optimal and secure communication of real time data over a CDMA based IP RAN network. In the process of data transmission, a new coding approach for security enhancement and quality improvement based on spectrum utilization and antenna coding is suggested. The traffic model is developed for image and audio data transmission over a wireless channel, having an interference of A...
CDMA is communication systems in mobile radio networks. To improve CDMA systems, new spreading sequences have been proposed. To design spreading sequences, it is necessary to increase the SNR. In classical approaches, the denominator of the SNR is not differentiable. We transform the SNR formula with the two types of orthogonal basis vectors. The denominator of this expression is differentiable. We...
Code-Division Multiple-Access (CDMA) [1] is widely used in both civil and military applications. It does take advantages from the system characteristics. For example, higher data rate and user capacity, better multipath resolution [2] and resistance to jamming, low probability of interception, accurate timing and ranging, and more importantly, stronger ability to suppress interference and jamming...
The Coverage and Capacity are the essential parameters that defines the performance of a cellular system. But, these are restricted by the interference in the system. The Co-Channel Interference(CCI) is one of the major sources of interference which exists mainly due to the concept of frequency reuse. The effect of CCI is more in CDMA based systems because the frequency reuse ratio is unity in those...
In modern wireless networks especially in Machine-to-Machine (M2M) systems and in the Internet of Things (IoT) there is a high densities of users and spatial reuse has become an absolute necessity for telecommunication entities. This paper studies the maximum throughput of Carrier Sense Multiple Access (CSMA) in scenarios with spatial reuse. Instead of running extensive simulation with complex tools...
This paper proposes a channel state information (CSI) weighting combining scheme for a successive interference canceller (SIC). In general, SIC performance is degraded by the estimation errors in CSI caused by interference and temporal channel variations. This paper introduces a scheme to appropriately weight and combine pre-CSI, defined as CSI estimated for transmitting power control (TPC), and post-CSI,...
Wireless communication with multicarrier modulation is very attractive for present and future communication network due to immunity to delay spread and fading. However, such systems are receptive to carrier frequency offset (CFO) due to Doppler effect in a mobile communication system. Analysis is carried out for a wireless communication system with multi carrier (MC) direct sequence (DS) code division...
Code assignment In the CDMA network has been a major area of study concerned with more spatial use of the codes and reduced interferences in the network. Some of the major code assignment techniques that have been proposed so far are mainly RCA, TCA, PCA and hybrid TCA-PCA. Each of these code assignment techniques face some interferences after the code assignment. In this paper, we have discussed...
The aim of this work is to study the capacity of the three dimensional cellular Air-to-Ground system. Calculations have been done through simulations of the Outside Cell Interference Factor (OCIF), for reverse and forward link, by using seven rings of interfering cells around the desired cell, for various values of the maximum height of the cell and its radius. A Case Study for the major Greek airports...
Millimeter wave (mmWave) systems will likely employ large antenna arrays at both the transmitters and receivers. A natural application of antenna arrays is simultaneous transmission to multiple user equipments (UEs), which requires multi-user precoding at the transmitter. However, hardware constraints and operation loads make it challenging to apply conventional pure MIMO digital precoding or even...
The growth of customers in 3G network has forced the operators to always optimize their network performances. One of the most concerned parameters to indicate the quality of network is the interference area. Especially in 3G network, this parameter is directly influenced by the number of users. Hence, it would be better if the operators can predict the areas experiencing interference before getting...
In smart grids, the critical packets generated by an Electrical Device (ED) at the customer site must be communicated to a control station with minimal delay so that corrective measures, if required, can be initiated quickly at the site. This paper presents the modelling of Wireless Mesh Backbone Network (WMBN) to which customer sites are connected in a smart grid. The WMBN is comprised of Mesh Routers...
The downlink performance of two-tier (macro/pico) multi-antenna cellular heterogeneous networks (HetNets) employing space division multiple access (SDMA) technique is analyzed in this paper. The number of users simultaneously served with SDMA by each BS in a resource block depends on user distribution, unlike previous studies which assume the number to be any arbitrary value. By exploiting the feasibility...
Spatial throughput (i.e. throughput with spatial reuse) is important with new types of networks such as vehicular, sensor and military networks. The aim of this study is to compute the spatial throughput of Aloha and CSMA using tools for stochastic geometry. Our network nodes will be modeled as elements of a Poisson Point Process (PPP) of a one- or two-dimensional space. Spatial Aloha can be modeled...
This paper presents a detailed mathematical model of DS-CDMA systems based on binary and chaotic spreading sequences in the case when interleavers are used to mitigate multipath fading in wideband channel. The interleaving techniques were well investigated in these systems in the case when flat fading and noise were present in the channel. However, a comprehensive analysis of systems with interleavers,...
In satellite networks, the design of MAC schemes which achieve high performance is an important and widely studied problem. Random access is recognized as an appealing solution for these scenarios. In the literature so far, two main research lines have been followed: diversity slotted Aloha-like protocols and spread spectrum Aloha schemes. The goal of this work is to analyze the performance of these...
The digital-analog hybrid beamforming technique with a number of antennas is necessary for the millimeter wave (mmWave) communications to overcome both high complexity of large array system and high path loss of mmWave signals. Since the hybrid beamforming system has multiple radio-frequency (RF) chains, the simultaneous transmission is possible which is known as the space division multiple access...
Power control and carrier allocation are the main focus of work on interference management in 3G heterogeneous networks. This work introduces interference management in 3G small base stations by coordinating the allocation of orthogonal variable spreading factor codes (OVSF) in order to improve both the guaranteed data rate and the system sum rate. The coordination is done by a centralised controller...
Transmission of information in nano-networks can be implemented by the emission and reception of molecules in diffusion-based molecular communications. Since the propagation environment is shared among multiple nodes, the molecules emitted by different transmitters cause interuser interference (IUI). In this paper, we propose molecular code division multiple access (MCDMA) to overcome the IUI caused...
The use of Active Antenna Systems (AAS) in mobile communications has a number of advantages; the transmitted signal is focused, which results in a reduction of power required per connection, and the interference towards other users can be reduced, so the capacity of the system can be increased. One of the questions which arise in designing an AAS, is how to properly determine the current excitations...
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