The Ergodic Rate Density of Slotted and Unslotted CSMA Ad-Hoc Networks

The Ergodic Rate Density of Slotted and Unslotted CSMA Ad-Hoc Networks

The Ergodic Rate Density of Slotted and Unslotted CSMA Ad-Hoc Networks

 

ABSTRACT:

          The performance of random Wireless Ad-hoc Networks (WANETs) is primarily limited by their self-interference. The utilization of a decentralized Carrier Sensing Multiple Access (CSMA) protocol protects the participating receivers from the presence of strong interferers and enhances the performance compared to the simpler ALOHA protocol.

 

OBJECTIVE:

We analyze the ERD of slotted and unslotted CSMA WANETs. The framework focuses on the access protocol and the physical layer processing and adopts a probabilistic simplified model to characterize the operation of higher communication layers. For the slotted CSMA variant the transmissions are restricted to the boundaries of predefined time slots whereas the unslotted variant is based on asynchronous access to the medium. The performance of both variants is evaluated as a function of the back-off probability.

 

INTRODUCTION:

  • Wireless Ad-hoc Networks (WANETs) are wireless networks that do not depend on a preexisting infrastructure and therefore are suitable for many applications. WANETs are primarily characterized by multi-hop communication, offering scalability and flexibility.
  • The Medium Access Control (MAC) protocol is the set of rules that defines the access procedure to the shared medium. The MAC protocols of WANETs are decentralized by nature and have a significant impact on network performance. Traditionally, MAC protocols are divided into slotted type and unslotted type MAC protocols
  • The use of the term slotted to characterize a MAC protocol has several meanings in the literature. In the following paper the term slotted protocol refers to access protocols in which the time axis is divided into slots and each transmission occupies a single slot.

 

EXISTING SYSTEM:

Stamatiou and M. Haenggi, “Random-access poisson networks:stability and delay,” IEEE Communications Letters, vol. 14, no. 11,pp. 1035–1037, 2010.

  • The pure randomness of the ALOHA protocols was shown to be inefficient for large amount of terminals and to result in a throughput-stability tradeoff

Yang and N. Vaidya, “On physical carrier sensing in wireless adhocnetworks,” in Proceedings of the International Conference on ComputerCommunications (INFOCOM), 2005, vol. 4, pp. 2525–2535.

  • The optimal carrier sense threshold that maximizes the network throughput was shown to be larger compared to the case in which the MAC overhead
  • is not considered

.

DRAWBACKS:

  • The main barrier for the analysis of large scale CSMA networks is the modeling of the random position of active nodes.
  • The performance of slotted CSMA WANET grows exponentially with the back-off probability under an outage model.
  • The impact of the CSMA protocol overhead onthe network performance.  

PROPOSED SYSTEM:

    • We analyze the Ergodic Rate Density (ERD) of slotted and unslotted CSMA WANETs in the small back-off probability regime.
    • Our main result is the derivation of simple expressions which describe the ERD of CSMA WANETs as a function of the back-off probability, the path-loss exponent and the ERD of the same WANET when applying the ALOHA protocol.
    • The ERD expressions for both the slotted and the unslotted variants are shown to grow with the back-off probability.
  • 401
  • DESCRIPTION:
  • We consider a decentralized wireless ad-hoc network (WANET), which utilizes a CSMA Medium Access Control (MAC) protocol. The locations of the transmitters in the network are random, and modeled by a two dimensional homogenous Poisson Point Process (PPP) with a density of λp. Following the CSMA protocol, described in subsection II-B, some of the nodes gain access to the medium and become active transmitters. Each active transmitter has a specific destination node, and together they form a pair. We mark the paired nodes by a common index; i.e., receiver i is always paired with transmitter i.

     List of All Major Assumptions

    1) All transmitters have data to transfer at any given time.

    2) The distance between each transmitter and its paired receiver is equal to d for all pairs, while the relative angle between a transmitter and its paired receiver is distributed uniformly over [0, 2π].

    3) The effect of signaling miss-detections and collisions as well as the contribution of the signaling messages to the aggregate interference is negligible.

    4) The channels and the location of nodes do not change during packet transmission.

    5) The location of the interferers as well as the channel gains at different transmissions attempts are statistically independent.

    402

 

ADVANTAGE:

  • The evaluation of the system parameters that maximize the network performance.
  • The performance of both variants is evaluated as a function of the back-off probability.
  • Capability to predict the optimal system parameters with very good accuracy.
  • The ERD expressions for both the slotted and the unslotted variants are shown to grow with the back-off probability.

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

 

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS:

    • Operating system           :         Windows 7.
    • Coding Language :         MATLAB
    • Tool                     :         MATLAB R2013A
Suppressing Alignment: Joint PAPR and Out-of-Band Power Leakage Reduction for OFDM-Based Systems

Suppressing Alignment: Joint PAPR and Out-of-Band Power Leakage Reduction for OFDM-Based Systems

Suppressing Alignment: Joint PAPR and Out-of-Band Power Leakage Reduction for OFDM-Based Systems

ABSTRACT:

Orthogonal frequency division multiplexing (OFDM) inherently suffers from two major drawbacks: high out-of-band (OOB) power leakage and high peak-to-average power ratio (PAPR). This paper proposes a novel approach called suppressing alignment for the joint reduction of the OOB power leakage and PAPR. The proposed approach exploits the temporal degrees of freedom provided by the cyclic prefix (CP), a necessary redundancy in OFDM systems, to generate a suppressing signal, that when added to the OFDM symbol, results in marked reduction in both the OOB power leakage and PAPR. Additionally, and in order to not cause any interference to the information data carried by the OFDM symbol, the proposed approach utilizes the wireless channel to perfectly align the suppressing signal with the CP duration at the OFDM receiver. Essentially, maintaining a bit error rate (BER) performance similar to legacy OFDM without requiring any change in the receiver structure.

INTRODUCTION

Orthogonal frequency division multiplexing (OFDM) is widely regarded as the multicarrier transmission of choice used in most of the existing broadband communication standards, e.g., WiFi, WiMAX, LTE, and IEEE 802.22 WRAN. This prevalent adoption of OFDM is due to its numerous advantages such as high spectral efficiency, tolerance to multipath fading, waveform agility, and simple equalization. However, despite all these attractive features, OFDM suffers from two major drawbacks: 1) out-of-band (OOB) power leakage as a result of its high spectral side lobes and 2) high peak-to-average power ratio (PAPR). Both of these shortcomings have a large impact on the performance of OFDM and can greatly limit its practical applications. For example, the high spectral side lobes, if not treated, can create severe interference to users operating in adjacent channels. The high spectral side lobes are caused primarily because of the inherent use of rectangular pulse shaping in the generation of OFDM, which behaves as a sinc function in the frequency domain with a spectrum that decays.

EXISTING SYSTEMS:

1)OOB reduction techniques

Effective way of suppressing the spectral side lobes, where an extended guard interval is added to the OFDM symbol to smooth the transitions between successive symbols

DRAWBACK

  • High spectral spreading
  • PAPR control is not considered

2)Traditional time domain windowing 

Windowing algorithms reduce the spectral efficiency, especially when the added guard interval is large.

DRAWBACK:

  • Error performance degradation
  • Power leakage increased

PROPOSED SYSTEM

  • We herein propose an novel algorithm, that we call suppressing alignment, for the joint suppression of both the OOB leakage and PAPR without any reduction in the transmission rate. Our algorithm exploits the temporal degrees of freedom provided by the cyclic prefix (CP), a necessary redundancy in OFDM systems, to properly design a suppressing signal that can effectively reduce both the OOB power leakage and PAPR of the OFDM signal. In particular, our approach adds another dimension to the use of the CP. Traditionally, the CP has been exploited mainly to mitigate the impact of inter-symbol interference (ISI) in multipath fading channels. In this work, we extend that functionality by also utilizing the CP for the purpose of spectral emissions suppression and PAPR reduction. Besides exploiting the CP, our design also utilizes the wireless channel to align the generated suppressing signal with the CP duration of the OFDM symbol at the receiver. By doing so, the suppressing signal will not cause any interference to the data portion of the OFDM symbol. From an interference point of view, the data carried in the OFDM symbol appears to be corrupted by the suppressing signal at the transmitter. However, after passing through the channel, the suppressing signal is perfectly aligned with the CP. In light of such alignment, the data portion of the OFDM symbol appears completely free of interference to the receiver. Thus, after discarding both the CP and the aligned suppressing signal through a simple CP removal operation, the receiver can decode the data with an error performance similar to that of standard OFDM.

BLOCK DIAGRAM:

391

DESCRIPTION

We consider a single link OFDM system consisting of a transmitter and a receiver communicating over a Rayleigh multipath channel.

For ease of analysis and without any loss of generality, we assume an adjacent user, employing OFDM or any other technology, operating over a bandwidth spanning K subcarriers within the transmission band of the OFDM system. Therefore, the OFDM transmitter/receiver pair should control their transmissions such that minimal interference is caused to this adjacent user. Let the total number of subcarriers be N, where the subcarriers spanning the adjacent user band To mitigate the effects of ISI, a CP of length L samples, which is assumed to be larger than the maximum delay spread of the channel, is added to the start of the OFDM symbol. To control the spectral emissions of the transmitted signal as well as its PAPR, the OOB-PAPR suppression block generates a time-domain suppressing signal c = [c1; :::; cN+L]T with the same length as the OFDM signal.

The suppressing signal c or equivalently (Ps) is designed under two goals in mind: 1) to minimize the OOB power leakage of the transmitted signal in the adjacent band and 2) to avoid causing any interference to the information data carried by the OFDM symbol, in the sense that the receiver is able to recover all information data sent by the transmitter. PAPR is an important metric for multi-carrier systems. Any increase in the PAPR might drive the power amplifier at the transmitter to operate in the non-linear region. This canpotentially cause spectral regrowth in the sidelobes, erasing any OOB reduction gains achieved before the power amplifier.

We propose to jointly minimize the PAPR and OOB power leakage to avoid such problem. The PAPR of the transmitted signal is the ratio of the maximum instantaneous power to the average power

ADVANTAGES

  • Reduced PAPR
  • Reduction in OOB power leakage
  • Low BER without effect in spectral efficiency

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Anas Tom, Student Member, IEEE, Alphan ¸Sahin, Member, IEEE, and Hüseyin Arslan, Fellow, IEEE, “Suppressing Alignment: Joint PAPR and Out-of-Band Power Leakage Reduction for OFDM-Based Systems”, IEEE Transactions on Communications, 2016.

Self-Sustainable Communications with RF Energy Harvesting: Ginibre Point Process Modeling and Analysis

Self-Sustainable Communications with RF Energy Harvesting: Ginibre Point Process Modeling and Analysis

Self-Sustainable Communications with RF Energy Harvesting: Ginibre Point Process Modeling and Analysis

 

ABSTRACT:

RF-enabled wireless power transfer and energy harvesting has recently emerged as a promising technique to provision perpetual energy replenishment for low-power wireless networks. The network devices are replenished by the RF energy harvested from the transmission of ambient RF transmitters, which offers a practical and promising solution to enable self-sustainable communications.

 

OBJECTIVE:

Analytically that the power-splitting architecture outperforms the time-switching architecture in terms of transmission outage performances. Lastly, our analysis provides guidelines for setting the time-switching and power-splitting coefficients at their optimal values.

Consider the point-to-point downlink transmission between an access point and a battery-free device in the cellular networks, where the ambient RF transmitters are randomly distributed following a repulsive point process, called Ginibre–determinantal point process(DPP).

 

INTRODUCTION:

  • Wireless communication powered by energy harvested from the natural environment, e.g., wind and tide, or power sources such as wireless energy transmitters has enabled self sustainable communications maintaining and operating in an autonomous manner, without human intervention . Self sustainable communications, understood to integrate various technologies including signal processing, circuit design, powers cavenging and management, etc., is envisioned to be the next momentous development in the green mobile ecosystem.
  • The probability that the RF-powered device is unable to meet its information throughput requirement, due to an insufficient transmit power and/or interference.

  • Numerical results corroborate our closed-form expressions we derive the closed-form expectation of the aggregated energy harvesting rate of the RF-powered device as a function of the density of ambient transmitters. Numerical results corroborate our closed-form expressions

 

EXISTING SYSTEM:

Lu, P. Wang, D. Niyato, D. I. Kim, and H, Zhu, “Wireless Networkswith RF Energy Harvesting: A Contemporary Survey,” IEEE Communications Surveys and Tutorials, vol. 17, no. 2, pp. 757-789, May 2015.

  • The existing efforts have primarily focused onthe hardware circuit design to improve the energy harvestingefficiency as well as the resource allocation and performanceanalysis in wireless networks with RF energy harvesting.

 

M. Tentzeris, A. Georgiadis, and L. Roselli, “Energy Harvesting andScavenging,” Proceedings of the IEEE, vol. 102, no. 11 pp. 1644-1648,Nov. 2014.

  • RF-powered communications is also expected to have a profound impact on the development and machine-to-machine communications.

 

DRAWBACKS:

    • Energy efficiency and perpetual maintenance are two critical issues in self-sustainable communications.
    • Machine-type communications(MTC) , and autonomous sensor networking
    • Implementation for low-power energy-constrained electrical equipments such as IoT sensors and radio frequency identification (RFID) tags.
    • RF energy harvesting becomes a particularly suitable alternative technique for replenishing wireless communication Devices .

 

PROPOSED SYSTEM:

  • This paper adopts a stochastic geometry framework based on the Ginibre model to analyze the performance of self-sustainable communications over cellular net-works with general fading channels.
  • Two practical RF energy harvesting receiver architectures, namely time-switching and power-splitting, are investigated.
  • Perform an analytical study on the RF-powered device and derive the expectation of the RF energy harvesting rate, the energy outage probability and the transmission outage probability over Nakagami-m fading channels.

 

BLOCK DIAGRAM:

 381

DESCRIPTION:

We consider an RF-powered device powered solely by the energy harvested from the RF signals transmitted by ambient RF transmitters. We assume that the ambient RF transmitters are distributed as a general class of point processes. It is further assumed that the RF-powered device is battery less. In other words, the device utilizes the instantaneously harvested RF energy to supply its operations. We investigate two co-located receiver architectures, namely, time-switching and power-splitting.

An information decoder to share the same antenna, and both of them observe the same channel condition.

  • Time-Switching Architecture: The time-switching architecture operates on a time-slot based manner. That is, either the information receiver or the RF energy harvester is connected to the antenna at a giventime. Specifically, this architecture first uses τ portion of time to harvest energy. Then during the remaining 1 –τ portion of time, the RF-powered device uses the energy reserved from the capacitor to decode information.
  • Power-Splitting Architecture: In the power-splitting architecture, the received RF signals are divided into two streams with different power levels for the information decoder and RF energy harvester. The power splitter is able to adjust the power ratio between two streams. We denote the portion of RF signals flowed to the energy harvester by ρ, and that to the information receiver by 1 − ρ. In this work, we consider downlink SWIPT from the base station or access point to the RF-powered device

    •  

For the time-switching architecture, the device alternately performs energy harvesting and information decoding. For the power splitting architecture, the device performs energy harvesting and information decoding simultaneously. We assume that the capacitors of the both architectures are lossless.

 

ADVANTAGE:

    • The performance metrics of the RF-powered device over a cellular network
    • With randomly-located ambient RF transmitters modeled As a Ginibre α-DPP.
    • The emerging self sustainable communications with RF energy harvesting has found its applications in low-power wireless systems,
    • Efficiently with modern techniques from numerical analysis.
    • Lower transmission outage probability

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

 

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS: 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A
Secure Broadcasting with Imperfect Channel State Information at the Transmitter

Secure Broadcasting with Imperfect Channel State Information at the Transmitter

Secure Broadcasting with Imperfect Channel State Information at the Transmitter

ABSTRACT:

We investigate the problem of secure broadcasting over fast fading channels with imperfect main channel state information (CSI) at the transmitter. In particular, we analyze the effect of the noisy estimation of the main CSI on the throughput of a broadcast channel where the transmission is intended for multiple legitimate receivers in the presence of an eavesdropper. Besides, we consider the realistic case where the transmitter is only aware of the statistics of the eavesdropper’s CSI and not of its channel’s realizations. First, we discuss the common message transmission case where the source broadcasts the same information to all the receivers, and we provide an upper and a lower bounds on the ergodic secrecy capacity. For this case, we show that the secrecy rate is limited by the legitimate receiver having, on average, the worst main channel link and we prove that a non-zero secrecy rate can still be achieved even when the CSI at the transmitter is noisy. Then, we look at the independent messages case where the transmitter broadcasts multiple messages to the receivers, and each intended user is interested in an independent message. For this case, we present an expression for the achievable secrecy sum-rate and an upper bound on the secrecy sum-capacity and we show that, in the limit of large number of legitimate receivers K, our achievable secrecy sum-rate follows the scaling law log((1−_) log(K)), where _ is the estimation error variance of the main CSI. The special cases of high SNR, perfect and no-main CSI are also analyzed. Analytical derivations and numerical results are presented to illustrate the obtained expressions for the case of independent and identically distributed Rayleigh fading channels.

OBJECTIVE

  • Discussion of common message sharing and we provide anupper and a lower bounds on the ergodic secrecy capacity.
  • We look at the independent messages case where the transmitter broadcasts multiple messages to the receivers, and each intended user is interested in an independent message.
  • SNR Analysis

INTRODUCTION

  • Ensuring the confidentiality of the users is one of the key challenges of wireless communication systems. To date, securing a communication is mainly performed at the application layer using cryptographic protocols. From a research perspective, it has been shown that securing a transmission can be enhanced at the physical layer without the use of cryptography.
  • We investigate the problem of secure broadcasting over fast fading channels with imperfect main channel state information (CSI) at the transmitter. In particular, we analyze the effect of the noisy estimation of the main CSI on the throughput of a broadcast channel where the transmission is intended for multiple legitimate receivers in the presence of an eavesdropper. Besides, we consider the realistic case where the transmitter is only aware of the statistics of the eavesdropper’s CSI and not of its channel’s realizations

EXISTING SYSTEM

Method 1: Eavesdropper’s channels

This model is supposed to be independent from each other and considered to be more suitable to analyze secrecy in mobile communication systems.

The imperfect CSI has an upper and lower bounds on the secrecy capacity were presented for single user transmission. Works in this area generally assume that at least the statistics of the eavesdropper’s fading channel are known to the transmitter.

LIMITATIONS

When a common message is broadcasted to all the legitimate receivers, the secrecy capacity performance is limited by the user with the worst channel quality

Also, the transmission scheme, achieving the proposed secrecy rate, is elaborated in such a way to avoid any extra leakage of information to the eavesdropper.

When multiple independent messages are broadcasted, a genie-aided channel must be carefully selected to obtain the proposed upper bound. This upper bound is shown to be tight in the very noisy CSI extreme.

 

PROPOSED SYSTEM MODEL:

In particular, we analyze the effect of the noisy estimation of the main CSI on the throughput of a broadcast channel where the transmission is intended for multiple legitimate receivers in the presence of an eavesdropper. Besides, we consider the realistic case where the transmitter is only aware of the statistics of the eavesdropper’s CSI and not of its channel’s realizations. First, we discuss the common message transmission case where the source broadcasts the same information to all the receivers, and we provide an upper and a lower bounds on the ergodic secrecy capacity. For this case, we show that the secrecy rate is limited by the legitimate receiver having, on average, the worst main channel link and we prove that a non-zero secrecy rate can still be achieved even when the CSI at the transmitter is noisy. Then, we look at the independent messages case where the transmitter broadcasts multiple messages to the receivers, and each intended user is interested in an independent message. For this case, we present an expression for the achievable secrecy sum-rate and an upper bound on the secrecy sum-capacity and we show that, in the limit of large number of legitimate receivers K, our achievable secrecy sum-rate follows the scaling law log((1−α) log(K)), where αis the estimation error variance of the main CSI. The special cases of high SNR, perfect and no-main CSI are also analyzed. Analytical derivations and numerical results are presented to illustrate the obtained expressions for the case of independent and identically distributed Rayleigh fading channels.

BLOCK DIAGRAM

          The channel gains hk and g are independent, ergodic and stationary. We consider that the transmitter is only aware of the statistics of the eavesdropper’s CSI and not of its channel’s realizations g(i). Also, we assume that the transmitter is only provided with a noisy version of each hk(i), say ˆhk(i)∼CN(0, 1), such that the main channel estimation model.

371

To ensure correct decoding with high probability at the legitimate receivers’ side, we assume that each receiver Rk has a perfect knowledge of its channel gain hk(i). Also, we assume that the eavesdropper is aware of its channel gain g(i), and of all the legitimate receivers’ channel gains hk(i), k ∈ {1, · · · ,K}. The estimated channel gains ˆh k(i), k ∈ {1, · · · ,K}, are known globally.

ADVANTAGES

          Can be used in SISO and MIMO system designs

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

 

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS: 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Amal Hyadi, Student Member, IEEE, Zouheir Rezki, Senior Member, IEEE, Ashish Khisti, Senior Member, IEEE, and Mohamed-Slim Alouini, Fellow, IEEE, Secure Broadcasting with Imperfect Channel State Information at the Transmitter, IEEE Transactions on Wireless Communications, 2016.

Queue-Aware Energy-Efficient Joint Remote Radio Head Activation and Beamforming in Cloud Radio Access Networks

Queue-Aware Energy-Efficient Joint Remote Radio Head Activation and Beamforming in Cloud Radio Access Networks

Queue-Aware Energy-Efficient Joint Remote Radio Head Activation and Beamforming in Cloud Radio Access Networks

ABSTRACT:

In this paper, we study the stochastic optimizationof cloud radio access networks (C-RANs) by joint remote radiohead (RRH) activation and beamforming in the downlink

OBJECTIVE:

Leveraged on low power node and cloud computing, the cloud radio access network (C-RAN), first proposed in is expected to revolutionize the architecture and operations of future wireless systems, and it has attracted considerable amount of attentions in both academia and industry.

INTRODUCTION:

The fifth-generation (5G) wireless networks are expected to provide ubiquitous services to a larger number of simultaneous mobile devices with device density far beyond the current wireless communication systems. To cope with these challenges, ultra-dense low power nodes and cloud computing are regarded as two of the most promising techniques.

A large number of remote radio heads (RRHs) are densely deployed in the space domain for C-RANs. Each RRH is configured only with the front radio frequency (RF) components and some basic transmission/reception functionalities. The RRHs are connected to the baseband unit (BBU) pool through high-bandwidth and low-latency front haul links to enable real-time cloud computing. The C-RANs can act as a platform for the practical implementation of coordinated multi-point (CoMP) transmission concepts.

The signals observed at each UE are super positions of signals from multiple active RRHs. The beamforming weight coefficients are designed to steer the data to their intended receivers in the spatial domain. That is, for a given UE, the desired signals are combined coherently yet the interfering signals are combined out-of-phase. Here the joint beamforming aims to improve the signal-to-interference plus-

noise ratio (SINR) in order to significantly improve the spectral efficiency of C-RANs.

 

EXISTING SYSTEM:

Peng, C. I, C. Tan, and C. Huang, “IEEE access special sectioneditorial: Recent advances in cloud radio access networks,” IEEE Access,vol. 2, pp. 1683C1685, Dec. 2014.

  • The C-RANs can act as a platform for the practical implementation of coordinated multi-point (CoMP) transmission concepts.

Peng, Y. Li, T. Quek, C. Wang, “Device-to-Device underlaid cellularnetworks under Rician fading channels,” IEEE Trans. Wireless Commun.,vol. 13, no. 8, pp. 4247C4259, Aug. 2014.

  • The authors investigated stochastic control for wireless networks with finite buffers, where the joint flow control, routing, and scheduling algorithms can achieve high network utility and deterministically bounded backlogs inside the network.

 

 

DRAWBACKS:

  • Deterministically bounded backlogs inside the network.
  • The delay analysis was conducted in suboptimal scheduling in one-hop wireless networks.
  • Considering the effects of random traffic arrivals and time-varying channel fading.
  • Leveraging on the Lyapunov optimization technique.
  • Only consider a static optimization framework with full traffic buffers.

 

PROPOSED SYSTEM:

Optimization based WMMSE algorithm and the relaxed integer programming based WMMSE algorithm are proposed to efficiently obtain the joint RRH activation and beamforming policy. Both algorithms can converge to a stationary solution with low-complexity and can be implemented in a parallel manner, thus they are highly scalable to large-scale C-RANs. In addition, these two proposed algorithms provide a flexible and efficient means to adjust the power-delay tradeoff on demand.

BLOCK DIAGRAM:

361

DESCRIPTION:

  • Scenario Description

We consider a downlink C-RAN with K RRHs and I UEs, where each RRH is equipped with M antennas and each UE has N antennas. Let K and I denote the set of RRHs and the set of UEs, respectively. The bandwidth of the system isW. We also assume that the network operates in slotted time with time dimension partitioned into decision slots indexed byt {0, 1, 2, …}with slot duration τ .

The achievable data rate in the unit of bps/Hz of UE I is given by

 

  1. Network Power Consumption Model

In C-RANs, the extensive use of high-capacity low-latency bfronthaul links makes the fronthaul power consumption comparable to the transmission power of RRHs. Here we consider the passive optical network to provide the effective high-capacity fronthaul connections between the RRHs and the BBU pool.

 

  1. Queue Stability and Problem Formulation

The BBU pool maintains I traffic queues for the random traffic arrivals towards I UEs. Let A(t) = [A1(t), …,AI (t)]be the vector of stochastic traffic data arrivals (bits) at the endof slot t. We assume that the traffic arrival Ai(t) is independent

w.r.t. iand i.i.d. over slots according to a general distribution with mean E[Ai(t)] = λi. Let Q(t) = [Q1(t), …,QI (t)]denote the vector of queue state information (QSI) (bits) for the I UEs at the beginning of slot t. Therefore, the queue dynamic for UE iis given by

ADVANTAGES:

  • Provide a flexible and efficient means to control the delay-power tradeoff on demand.
  • The problems considered in this paper are formulated as stochastic optimizations considering.
  • Random traffic arrivals, queuing delays, and the time-varying fading channels.
  • They are highly scalable to large-scale C-RANs.

 

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                            :           MATLAB R2013A
Placement Optimization of Energy and Information Access Points in Wireless Powered Communication Networks

Placement Optimization of Energy and Information Access Points in Wireless Powered Communication Networks

Placement Optimization of Energy and Information Access Points in Wireless Powered Communication Networks

ABSTRACT:

The applications of wireless power transfer technology to wireless communications can help build a wireless powered communication network (WPCN) with more reliable and sustainable power supply compared to the conventional battery-powered network. However, due to the fundamental differences in wireless information and power transmissions, many important aspects of conventional battery-powered wireless communication networks need to be redesigned for efficient operations of WPCNs. In this paper, we study the placement optimization of energy and information access points in WPCNs, where the wireless devices (WDs) harvest the radio frequency energy transferred by dedicated energy nodes (ENs) in the downlink, and use the harvested energy to transmit data to information access points (APs) in the uplink. In particular, we are interested in minimizing the network deployment cost with minimum number of ENs and APs by optimizing their locations, while satisfying the energy harvesting and communication performance requirements of the WDs. Specifically, we first study the minimum-cost placement problem when the ENs and APs are separately located, where an alternating optimization method is proposed to jointly optimize the locations of ENs and APs. Then, we study the placement optimization when each pair of EN and AP are co-located and integrated as a hybrid access point, and propose an efficient algorithm to solve this problem. Simulation results show that the proposed methods can effectively reduce the network deployment cost and yet guarantee the given performance requirements, which is a key consideration in the future applications of WPCNs.

OBJECTIVE

  • Formulation of the optimal node placement problem in WPCNs using either separated or co-located EN and AP.
  • Transform the minimum-cost deployment problem into its equivalent form that optimizes the locations of fixed number of ENs and APs
  • Propose an efficient cluster-based greedy algorithm to optimize the locations of ENs given fixed AP locations.
  • Trial-and-Error based algorithm is proposed to optimize the locations of APs given fixed ENs locations
  • Extend the greedy EN placement method under fixed APs to solving the HAP placement optimization, which is achieved by incorporating additional considerations of dynamic WD-HAP associations during HAP placement.

INTRODUCTION

The applications of wireless power transfer technology to wireless communications can help build a wireless powered communication network (WPCN) with more reliable and sustainable power supply compared to the conventional battery-powered network. However, due to the fundamental differences in wireless information and power transmissions, many important aspects of conventional battery-powered wireless communication networks need to be redesigned for efficient operations of WPCNs. Modern wireless communication systems, e.g., cellular networks and wireless sensor networks (WSNs), are featured by larger bandwidth, higher data rate and lower communication delays. The improvement on communication quality and the increased data processing complexity have imposed higher requirement on the quality of power supply to wireless devices (WDs).

 

EXISTING SYSTEM

Method 1: wireless powered communication network (WPCN), the operations of WDs, including data transmissions, are fully/partially powered by means of RF-enabled WPT           Problem: Energy efficiency is less and consuming more transmitting power while data transmission

          Solution 1: TDMA based WPCN using partially / fully powered HAP

          Solution 2: SDMA based WPCN using partially / fully powered HAP

          Solution 3: Using single antenna HAP and multi-antenna HAP

          Problem 2: HAP may lead to “doubly near far” problem due to distant displacement power loss

          Solution 4: Separately located ENs and APs are considered to more flexibly balance the energy and information transmissions in WPCNs

          Problem 3: These existing methods, problems and solutions are mostly dealing with transmitting power, time slot lengths based on Instantaneous Channel State Information (CSI).

PROPOSED SYSTEM DESIGN

In order to propose a novel algorithm for WPCN protocol, we study the node placement optimization problem in WPCNs, which aims to minimize the deployment cost on ENs and APs given that the energy harvesting and communication performances of all the WDs are satisfied.

 

IMPLEMENTATION PROCEDURE

1) We formulate the optimal node placement problem in WPCNs using either separated or co-located EN and AP. To simplify the analysis, we then transform the minimum-cost deployment problem into its equivalent form that optimizes the locations of fixed number of ENs and APs;

2) The node placement optimization using separated EN and AP is highly non-convex and hard to solve. To tackle the non-convexity of the problem, we first propose an efficient cluster-based greedy algorithm to optimize the locations of ENs given fixed AP locations. Then, a trial-and-error based algorithm is proposed to optimize the locations of APs given fixed ENs locations. Based on the obtained results, we further propose an effective alternating method that jointly optimizes the EN and AP placements;

3) For the node placement optimization using co-located EN and AP (or HAP), we extend the greedy EN placement method under fixed APs to solving the HAP placement optimization, which is achieved by incorporating additional considerations of dynamic WD-HAP associations during HAP placement. Specifically, a trial-and-error method is used to solve the WD-HAP association problem, which eventually leads to an efficient greedy HAP placement algorithm.

BLOCK DIAGRAM FOR THE PROPOSED ARCHITECTURE

351

For the case of separated ENs and APs, we consider the above Fig, a WPCN in R2 consisting of M ENs, N APs and K WDs, whose locations are denoted by 2 × 1 coordinate vectors {ui|i = 1, · · · ,M}, {vj |j = 1, · · · ,N}, and {wk|k = 1, · · · ,K}, respectively. We assume that the energy and information transmissions are performed on orthogonal frequency bands without interfering with each other. Specifically, the ENs are connected to stable power source and broadcast RF energy in the DL for the WDs to harvest the energy and store in their rechargeable batteries. At the same time, the WDs use the battery power to transmit information to the APs in the UL. The circuit structure of a WD to perform the above operations is also shown in the above Figure.

SCHEMATIC DIAGRAM FOR WPCN WITH CO-LOCATED ENS AND APS

352

353

ADVANTAGES

  • Reduce the network deployment cost
  • Long-term network performance optimization based mainly on the average channel gains
  • Energy harvesting and communication performances of all the WDs are satisfied

APPLICATIONS

  • Used to solve the WD-HAP association problem
  • WPCN instead of battery powered communication network
  • Used in WSN, BSN and WBSN

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS: 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Suzhi Bi, Member, IEEE and Rui Zhang, Senior Member, IEEE, “Placement Optimization of Energy and Information Access Points in Wireless Powered Communication Networks”, IEEE Transactions on Wireless Communications, 2016.

Performance of Low-Complexity Uniform Power Loading OFDM Systems with Reduced Feedback over Rayleigh Fading Channels

Performance of Low-Complexity Uniform Power Loading OFDM Systems with Reduced Feedback over Rayleigh Fading Channels

Performance of Low-Complexity Uniform Power Loading OFDM Systems with Reduced Feedback over Rayleigh Fading Channels

ABSTRACT:

In this paper, we consider a low-complexity uniform power loading scheme for orthogonal frequency division multiplexing (OFDM) systems with two reduced feedback mechanisms and analyze its performance over Rayleigh fading channels. In the first feedback mechanism, the receiver feeds back to the transmitter the channel gains and the indices of the best M subchannels; while for the second feedback mechanism, the receiver feeds back only the indices of the best M sub-channels. The available power budget is equally distributed over the best M subchannels for both feedback mechanisms. We derive closed form expressions for the achievable capacity and an upper bound on the outage capacity of the first and second mechanisms, respectively. A simple elimination algorithm is provided to find the optimal number of best subchannels M that maximizes the achievable capacity. Numerical results show the dependence of the optimal number of the best subchannels M on the system parameters. Additionally, the presented results interestingly show that the low-complexity uniform power loading scheme can achieve up to 98:72% of the channel capacity, obtained using the well-known waterfilling solution, when the optimal value of M is used. Moreover, the uniform power loading scheme can achieve up to 88:86% of the energy efficiency at reduced complexity.

 

OBJECTIVE:

  • The analysis can be used to find the optimal number of best subchannels such that the achievable capacity approaches the channel capacity2 for a given set of system parameters. In other words, given the average channel gain and the available power budget, one can easily find the optimum number of most reliable subchannels, M, to approach the channel capacity (and energy efficiency) without rocessing for every channel realization.
  • The presented analysis and numerical results justify that the uniform distribution of the available power budget of each user on its most reliable M subchannels can approach the channel capacity and EE, at reduced complexity

INTRODUCTION:

  • Orthogonal frequency division multiplexing (OFDM) has been standardized for many contemporary wireless systems due to its inherent advantages and flexibilities. The capacity of OFDM systems in frequency-selective channels can be maximized by adapting the transmit power per subcarrier to the varying channel quality according to the well known water filling solution.

  • The power loading scheme is of low-complexity as there is no need to excute the analysis for every channel realization. Numerical results show the dependence of the optimal number of the most reliable subchannels, M, on the system parameters, i.e., the average channel gain and the available power budget. With this optimal value of M, the low-complexity uniform power loading can reach up to 98:72% and 88:86% of the channel

EXISTING SYSTEM:

  • D. P. Palomar and J. R. Fonollosa, “Practical algorithms for a family of waterfilling solutions,” IEEE Trans. Signal Process. vol. 53, no. 2, pp. 686–695, Feb. 2005.
  • Numerous algorithms exist to find the water filling solution with varying complexities.
  • W.-C. Pao and Y.-F. Chen, “Adaptive gradient-based methods for adaptive power allocation in OFDM-based cognitive radio networks,” IEEE Trans. Veh. Technol., vol. 63, no. 2, pp. 836–848, Feb. 2014
  • A gradient-based method to allocate the power per subcarrier for OFDM-based cognitive radio networks operating in timevarying channels. 

DISADVANTAGES OF EXISTING SYSTEM:

  • They need to be performed for every channel realization, which increases the complexity of OFDM systems.
  • Adapting the power per subcarrier increases the peak-to-average-power-ratio (PAPR) of OFDM systems

PROPOSED SYSTEM:

  • We derive closed form expressions for the achievable capacity and an upper bound on the outage capacity of the first and second mechanisms, respectively. A simple elimination algorithm is provided to find the optimal number of best sub-channels M that maximizes the achievable capacity.
  • The proposed algorithms are iterative and should be executed for every channel realization, which increases the OFDM system complexity.
  • To reduce the feedback overhead of OFDM systems, recentworks studied the feedback of the strongest subcarriers only.
  • The low-complexity uniform power loading scheme can achieve up to 98:72% of the channel capacity, obtained using the well-known water filling solution, when the optimal value of M issued. Moreover, the uniform power loading scheme can achieve up to 88:86% of the energy efficiency at reduced complexity.

ADVANTAGES OF PROPOSED SYSTEM:

  • Increases the OFDM system complexity.
  • The uniform power loading scheme can achieve up to 88:86% of the energy efficiency at reduced complexity.
  • To reduce the feedback overhead of OFDM systems
  • The low-complexity uniform power loading scheme can achieve up to 98:72% of the channel capacity
  • The power loading scheme is of low-complexity as there is no need to execute the analysis for every channel realization
  • The optimal value of M that maximizes the achievable capacity is to be determined

SYSTEM ARCHITECTURE:

341

DESCRIPTION:

The considered OFDM system decomposes the signal band width into a set of N orthogonal narrowband sub-channels each of equal bandwidth W. Additionally, the OFDM transmitter distributes the available power budget S max over the most reliable M (out of N) sub-channels and uses these M sub-channels for transmission for every channel realization. The optimal value of M that maximizes the achievable capacity is to be determined.

In the first mechanism, the receiver feeds back the best M sub channel gains and their indices to the transmitter. This requires M b+N bits. In other words, the receiver feeds back a fixed number of the strongest sub channels M and their indices to the transmitter for every channel realization.

The optimal value of M that maximizes the achievable capacity is to be determined. On the other hand, in the second mechanism, the receiver feeds back only the indices of the best M sub channels this requires N bits.

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

 

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS: 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Ebrahim Bedeery and Md. Jahangir Hossainz, “Performance of Low-Complexity Uniform Power Loading OFDM Systems with Reduced Feedback over Rayleigh Fading Channels”, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, FEB. 2016.

 

Performance Characterization of Relay-Assisted Wireless Optical CDMA Networks in Turbulent Underwater Channel

Performance Characterization of Relay-Assisted Wireless Optical CDMA Networks in Turbulent Underwater Channel

Performance Characterization of Relay-Assisted Wireless Optical CDMA Networks in Turbulent Underwater Channel

ABSTRACT:

In this paper, we characterize the performance of relay-assisted underwater wireless optical code division multiple access (OCDMA) networks over turbulent channels. In addition to scattering and absorption effects of underwater channels, we also consider optical turbulence as a log-normal fading coefficient in our analysis. To simultaneously and asynchronously share medium among many users, we assign a unique optical orthogonal code (OOC) to each user in order to actualize OCDMA based underwater network. The most significant challenge in underwater optical communication is in the ability to extend the short range of its coverage. In order to expand the viable communication range, we consider multi-hop transmission to the destination. Moreover, we evaluate the performance of a relay assisted point-to-point UWOC system as a special case of the proposed relay-assisted OCDMA network. Our numerical results indicate significant performance improvement by employing intermediate relays, e.g., one can achieve 32 dB improvement in the bit error rate (BER) of 10 􀀀6 using only a dual-hop transmission in a 90 m point-to-point clear ocean link.

OBJECTIVE:

The BER performance of optical code division multiple access (OCDMA)-based underwater wireless networks for both up-and downlink transmissions. We considered all the disturbing effects of the medium to better model the underwater channel.

 

INTRODUCTION:

Underwater wireless optical communication (UWOC) systems are receiving growing attention for various underwater applications. As opposed to their traditional counterparts, i.e., acoustic communications, they have three main superiorities: higher bandwidth, lower latency and better security. Therefore, UWOC system can be regarded as an alternative to meet the requirements of high speed and large data underwater communications such as imaging, real-time video transmission, high throughput sensor networks, etc.

However, presently, UWOC is suitable only for ranges that are typically less than 100 m which hinders its extensive usage. This drawback is due to the fact that UWOC suffers from three main impairing effects: absorption, scattering and turbulence which cause loss, inter-symbol interference (ISI) and fading on the received optical signal, respectively.

             To overcome this limitation and therefore to extend the viable communication range, in this paper we propose multi-hop transmission over turbulent underwater channel. By this scheme, we divide a relatively long communication distance with severe absorption, scattering and fading effects to shorter ones, each with a much reduced absorption, scattering and fading effects; and therefore with acceptable performance.

 

EXISTING SYSTEM:

Korotkova, N. Farwell, and E. Shchepakina, “Light scintillation inoceanic turbulence,” Waves in Random and Complex Media, vol. 22,no. 2, pp. 260–266, 2012.

  • Evaluate the scintillation indexof optical plane and spherical waves propagating in underwaterturbulent medium.

Gerc¸ekcio˘glu, “Bit error rate of focused gaussian beams in weakoceanic turbulence,” JOSA A, vol. 31, no. 9, pp. 1963–1968, 2014.

  • The on-axis scintillation index of a focused Gaussian beam has been formulated in weak oceanic turbulence and by considering log-normal distribution for intensity fluctuations the average BER in such systems is evaluated.

DRAWBACKS:

    • The system performance for longer ranges
    • Extend the viable communication range
    • Long communication distance with severe absorption, scattering and fading effects
    • Reducing its interfering effect on the other sensors signals.

 

PROPOSED SYSTEM:

The most significant challenge in underwater optical communication is in the ability to extend the short range of its coverage. In order to expand the viable communication range, we consider multi-hop transmission to the destination. Moreover, we evaluate the performance of a relay assisted point-to-point UWOC system as a special case of the proposed relay-assisted OCDMA network.

To simultaneously and asynchronously share medium among many users, we assign a unique optical orthogonal code (OOC) to each user in order to actualize OCDMA based underwater network.

 

BLOCK DIAGRAM:

331

DESCRIPTION:

We consider a collection of M underwater users which are located nearby each other and are communicating with a relatively distant receiver or OBTS. To simultaneously and asynchronously share the medium among the various users, a specific OOC code with weight W and length F = Tb/Tc is assigned to each user, where Tb and Tc are bit and chip duration times, respectively. To guarantee that auto-and cross correlation constraints λa and λc are equal to unity, maximum allowable number of users is upper bounded by;

Note that each of the M users produces similar contribution in thefirst relay. Hence, the total received optical signal at the frontend of the first relay’s detector can be summarized as

Finally, for the depicted topology in Fig. 1,

where destination is an OBTS, due to the physical properties of OBTS the transmitter of the last hop must have relatively a wide beam divergence angle to better illuminate the separate photo detectors of the OBTS.

 

ADVANTAGES:

    • Underwater optical communication is in the ability to extend the short range of its coverage.
    • (OCDMA)-based underwater wireless networks for both up-and downlink transmissions.
    • Chip detect-and-forward strategy at the relay nodes.
    • The number of users violates the code weight uplink BER saturates to a constant value.
    • UWOC system obtained as a special case of the proposed relay-assisted OCDMA network.

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

 

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Mohammad Vahid Jamali, Farhad Akhoundi, and Jawad A. Salehi, Fellow, IEEE, “Performance Characterization of Relay-Assisted Wireless Optical CDMA Networks in Turbulent Underwater Channel”, IEEE Transactions on Wireless Communications, 2016.

Optimum Co-Design for Spectrum Sharing Between Matrix Completion Based MIMO Radars and a MIMO Communication System

Optimum Co-Design for Spectrum Sharing Between Matrix Completion Based MIMO Radars and a MIMO Communication System

Optimum Co-Design for Spectrum Sharing Between Matrix Completion Based MIMO Radars and a MIMO Communication System

ABSTRACT:

Spectrum sharing enables radar and communication systems to share the spectrum efficiently by minimizing mutual interference. Recently proposed multiple input multiple output radars based on sparse sensing and matrix completion (MIMOMC), in addition to reducing communication bandwidth and power as compared to MIMO radars, offer a significant advantage for spectrum sharing. The advantage stems from the way the sampling scheme at the radar receivers modulates the interference channel from the communication system transmitters, rendering it symbol dependent and reducing its row space. This makes it easier for the communication system to design its waveforms in an adaptive fashion so that it minimizes the interference to the radar subject to meeting rate and power constraints. Two methods are proposed. First, based on the knowledge of the radar sampling scheme, the communication system transmit covariance matrix is designed to minimize the effective interference power (EIP) to the radar receiver, while maintaining certain average capacity and transmit power for the communication system. Second, a joint design of the communication transmit covariance matrix and the MIMO-MC radar sampling scheme is proposed, which achieves even further EIP reduction

OBJECTIVE

  • Based on radar sampling scheme
  • Design and implementation of the communication system transmit covariance matrix
  • Design and implementation of joint design of the communication transmit covariance matrix and the MIMO-MC radar sampling scheme

INTRODUCTION

The operating frequency bands of communication and radar systems often overlap, causing one system to exert interference to the other. For example, the high UHF radar systems overlap with GSM communication systems, and the S-band radar systems partially overlap with Long Term Evolution (LTE) and WiMax systems. Spectrum sharing enables radar and communication systems to share the spectrum efficiently by minimizing mutual interference. Spectrum sharing is an emerging technology that can be applied to enable radar and communication systems to share the spectrum efficiently by minimizing mutual interference.

EXISTING SYSTEM

          Method 1: MIMO radars using compressive sensing (MIMO-CS)

          Method 2: MIMO radars via matrix completion (MIMO-MC)

          Problems: The interference is confined to the sampled entries of the data matrix, while after matrix completion the target echo power is preserved

 

PROPOSED SYSTEM

  • In our proposal, we study spectrum sharing between a special class of collocated MIMO radars and a MIMO communication system.
  • Two methods are proposed. The first method is a cooperative design; for a fixed radar sampling scheme, which is known to the communication system, the communication system optimally selects its precoding matrix to minimize the interference to the radar. The second method is a joint design, whereby the radar sampling scheme as well as the communication system precoding matrix are optimally selected to minimize the interference to the radar.

PROPOSED SYSTEM MODEL

321

322

PROPOSED ALGORITHM FOR A FIXED RADAR SAMPLING SCHEME

Suppose that the two systems have the same symbol rate and are synchronized in terms of sampling times (see Section V for the mismatched case). We do not assume perfect carrier phase synchronization between the two systems.

323

ADVANTAGES

  • It achieves EIP reduction in both of the methods proposed
  • Smaller EIP when number of TX antennas and RX antennas is moderately used
  • Less computational complexity
  • Less implementation complexity

APPLICATIONS

  • Radar systems with GSM communication system
  • Can be used in adaptive transmission approach

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

 

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS: 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Bo Li, Student Member, IEEE, Athina P. Petropulu, Fellow, IEEE, and Wade Trappe, Fellow, IEEE, “Optimum Co-Design for Spectrum Sharing Between Matrix Completion Based MIMO Radars and a MIMO Communication System”, IEEE Transactions on Signal Processing, 2016.

On the Capacity of the Intensity-Modulation Direct-Detection Optical Broadcast Channel

On the Capacity of the Intensity-Modulation Direct-Detection Optical Broadcast Channel

On the Capacity of the Intensity-Modulation Direct-Detection Optical Broadcast Channel

ABSTRACT:

The capacity of the intensity-modulation direct detection optical broadcast channel (OBC) is investigated, under both average and peak intensity constraints. An outer bound on the capacity region is derived by adapting Bergmans’ approach to the OBC. Inner bounds are derived by using superposition coding with either truncated-Gaussian (TG) distributions or discrete distributions. While the discrete distribution achieves higher rates, the TG distribution leads to a simpler representation of the achievable rate region. At high signal-to-noise ratio (SNR), it is shown that the TG distribution is nearly optimal. It achieves the symmetric-capacity within a constant gap (independent of SNR), which approaches half a bit as the number of users grows. It also achieves the capacity region within a constant gap. At low SNR, it is shown that on-off keying (OOK) with time-division multiple access (TDMA) is optimal. This is interesting in practice since both OOK and TDMA have low complexity. At moderate SNR (typically [0,8] dB), a discrete distribution with a small alphabet size achieves fairly good performance.

OBJECTIVE

  • To improve the capacity of any optical communication system with optimization in SNR we design and analyze the intensity-modulation direct detection optical broadcast channel (OBC).

INTRODUCTION

  • Over the last decade there has been an exponential growth of bandwidth-intensive services such as video on demand, cloud storage and social networking which require large volumes of data to be transmitted over long distances.
  • Based on current trends, this growth is likewise to continue, driving the need to increase transmission capacity.
  • However, in order to approach channel capacity the constellation itself needs to be modified with respect to information theory.

EXISTING SYSTEMS

  • Method 1: Nyquist wavelength division multiplexing (N-WDM)
  • Method 2:Time frequency packing
  • Method 3:Optical system using direct detection

PROBLEMS

  • Expense of increased receiver complexity
  • Inter carrier interference (ICI) caused by the non-orthogonal carrier spacing
  • Less spectrally efficient and transmission on a single polarization

PROPOSED SYSTEM

  • Developing outer and inner bounds on the capacity region of the channel, where the subcarriers are encoded using the QPSK format, over 80 km of standard single mode fiber (SSMF).
  • A multiple-input multiple-output (MIMO) equalizer, which is based on pilot-aided channel estimation using time multiplexed OFDM pilot symbols, is also developed to demultiplex the signals

311

DESCRIPTION

  • The input signal is generated as binary symbols. These signal doesn’t have and polarity at this stage.
  • If the binary signals are generated we need to process encoding. Encoding is a method which converts the individual binary bit to another format of binary data’s. In our implementation we are using Convolutional encoding.
  • Now we have to modulate the binary signal using QPSK as indicated in our paper.
  • Then we need to spit those polarized signal into two sections. X-Real part and Y-imaginary part of the symbol. Again we need to do the symbol mapping.
  • IFFT and FFT is the process of Frequency division multiplexing and de-multiplexing respectively. Then we have convert those parallel signal into serial for transmission of symbols into single channel or medium.
  • So the signals we are having is digital. To pass through the fiber channel we have to change to analog. Then the signals are transmitted to the channel as dual signal (parallel).
  • In fiber optic channel, the first and initial process is the IQ-modulator(In-phase and Quadrature –phase). PBC is the polarized beam combiner to pass into fiber.
  • Here we are using SSMF type of fiber. Then we have the design of coherent receiver.
  • Coherent receiver has number steps to accurately recover the original signal of transmitter.
  • To reduce the phase offset and phase noise we use the error compensation algorithm and MIMO equalizer is used to get the correct path of signal.
  • Finally the FFT is performed to get the original subcarriers. And ZF and SD is used to recover original binary data from the dual polarized subcarriers.

ADVANTAGES

  • Improve the Optical Transmission interms of signal accuracy
  • Can be used for simulating theoretical systems inexpensively
  • Avoidance of Interferences (ISI, ICI)
  • Any distance, bit rate and data pulse can be simulated.
  • Better OSNR is achieved.
  • All parameters are completely user defined

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

  • System                           :         Pentium Dual Core.
  • Hard Disk                      :         120 GB.
  • Monitor                         :         15’’ LED
  • Input Devices                 :         Keyboard, Mouse
  • Ram                               :         1GB.

SOFTWARE REQUIREMENTS: 

  • Operating system           :         Windows 7.
  • Coding Language :         MATLAB
  • Tool                     :         MATLAB R2013A

REFERENCE:

Anas Chaaban, Zouheir Rezki, and Mohamed-Slim Alouini, “On the Capacity of the Intensity-Modulation Direct-Detection Optical Broadcast Channel”, IEEE Transactions on Wireless Communications, 2016.