Design Implementation of Next Generation Wireless LAN for Mass Digital Cinema

We have been designing an over 1.2 Gbps throughput wireless for next generation WLAN system conform with IEEE802.11TGac’s requirements. It reaches 33 meter propagation distance by using 80MHz of bandiwdth on 5GHz band. 4x5 antennas configuration contribute 2nd-order diversity gain and maintain both the high throughput and performance. The Greenfield format preamble was proposed for its high efficiency. Novel phase rotation is employed to lower the PAPR signal. Run test for transmitting 90 frames of 40961714 pixels/frame under in-door channel model proves that the proposed system shall be considered for providing an excellent performance mass digital cinema. Index Terms—Gigabit wireless LAN, IEEE802.11 TGac, digital cinema transmissio

Design of an OFDM Physical Layer Encryption Scheme

This paper presents a new encryption scheme implemented at the physical layer of wireless networks employing orthogonal frequency-division multiplexing (OFDM). The new scheme obfuscates the subcarriers by randomly reserving several subcarriers for dummy data and resequences the training symbol by a new secure sequence. Subcarrier obfuscation renders the OFDM transmission more secure and random, whereas training symbol resequencing protects the entire physical layer packet but does not affect the normal functions of synchronization and channel estimation of legitimate users while preventing eavesdroppers from performing these functions. The security analysis shows that the system is robust to various attacks by analyzing the search space using an exhaustive key search. Our scheme is shown to perform better in terms of search space, key rate, and complexity in comparison with other OFDM physical layer encryption schemes. The scheme offers options for users to customize the security level and the key rate according to the hardware resource. Its low complexity nature also makes the scheme suitable for resource-limited devices. Details of practical design considerations are highlighted by applying the approach to an IEEE 802.11 OFDM system case study

Lo standard LTE

Per il sempre crescente traffico dati la rete mobile, attualmente basata sul sistema UMTS, sta cominciando a dimostrare i suoi limiti. Per questo il 3GPP (third Generation Partnership Project) ha avviato la standardizzazione di un nuovo sistema di telecomunicazioni mobile, chiamato LTE (Long Term Evolution), che migliora il precedente ponendo ambiziosi traguardi in quanto a prestazioni. Attualmente il sistema è ancora in fase sperimentale e le prime applicazioni commerciali si avranno solo tra il 2010-2011. Questa tesi ha lo scopo di studiare le principali caratteristiche del livello fisico dell'LTE e valutarne le prestazioni offert

Implementation of WiMAX physical layer baseband processing blocks in FPGA

This project thesis elaborates on designing a baseband processing blocks for Worldwide Interoperability for Microwave Access (WiMAX) physical layer using an FPGA. WiMAX provides broadband wireless access and uses OFDM as the essential modulation technique. The channel performance is badly affected due to synchronization mismatches between the transmitter and receiver ends so the transmitted signal received is not reliable as the OFDM deals with high data rate. This thesis includes the theory and concepts behind OFDM, WiMAX IEEE 802.16d standard and other blocks algorithms, its architectures used for designing as well as a presentation of how they are implemented. Here Altera’s FPGA has been used for targeting to the EP4SGX70HF35C2 device of the Stratix IV family. WiMAX use sophisticated digital signal processing techniques, which typically require a large number of mathematical computations. Here Stratix IV devices are ideally suited for these kinds of complex tasks because the DSP blocks have a combination of dedicated elements that perform multiplication, addition, subtraction, accumulation, summation, and dynamic shift operations. The WiMAX physical layer baseband processing architecture consists of various major modules which were simulated block wise in order to check its giving the correct output as required. The coding style used here is VHDL. The sub-blocks have been synthesized using Altera Quartus II v11. 0 and simulated using ModelSim Altera Edition 6.6d

Feasibility study of 5G low-latency packet radio communications without preambles

This thesis deals with the feasibility of having lower latency for radio communication of short packets, which is the major traffic in the fifth generation (5G) of cellular systems. We will examine the possibility of using turbo synchronization instead of using a long preamble, which is needed for Data-Aided (DA) synchronization. The idea behind this is that short packets are required in low-latency applications. The overhead of preambles is very significant in case of short packets. Turbo synchronization allows to work with short or null preambles. The simulations will be run for a turbo synchronizer which has been implemented according to the Expectation Maximization (EM) formulation of the problem. The simulation results show that the implemented turbo synchronizer outperforms or attains the DA synchronizer in terms of reliability, accuracy and acquisition range for carrier phase synchronization. It means that the idea of eliminating the preamble from the short packet seems practical. The only downward is that there is a packet size limitation for the effective functionality of turbo synchronizer. Simulations indicate that the number of transmitted symbols should be higher than 128 coded symbols

Direct-sequence spread-spectrum modulation for utility packet transmission in underwater acoustic communication networks

This thesis investigates the feasibility and performance of using Direct-Sequence Spread-Spectrum (DSSS) modulation for utility-packet transmission in Seaweb underwater wireless acoustic communications networks. Seaweb networks require robust channel-tolerant utility packets having a low probability of detection (LPD) and allowing for multi-user access. MATLAB code simulated the DSSS transmitter and receiver structures and a modeled channel impulse response represented the underwater environment. The specific modulation scheme implemented is direct-sequence, differentially encoded binary phase-shift keying (DS-DBPSK) with quadrature spreading. Performance is examined using Monte Carlo simulation. Bit error rates and packet error rates for various signal-to-noise ratios and channel conditions are presented and the use of a RAKE receiver, forward error-correction coding and symbol interleaving are examined for improving system performance.Lieutenant Commanader, Canadian NavyApproved for public release; distribution is unlimited

Evaluation of Interference-Cancellation Based MAC Protocols for Vehicular Communications

Vehicular communications form an important part of future intelligent transport systems. Wireless connectivity between vehicles can enhance safety in vehicular networks and enable new services such as adaptive traffic control, collision detection and avoidance. As several new algorithms are being developed for enhancing vehicle to vehicle wireless connectivity, it is important to validate the performance of these algorithms using reasonably accurate wireless channel models. Specifically, some recent developments in the medium access control (MAC) layer algorithms appear to have the potential to improve the performance of vehicle to vehicle communications; however, these algorithms have not been validated with realistic channel models encountered in vehicular communications. The aforementioned issues are addressed in this thesis and correspondingly, there are two main contributions - (i) A complete IEEE 802.11p based transceiver model has been simulated in MATLAB and its performance & reliability are tested using existing empirically-developed wireless channel models. (ii) A new MAC layer algorithm based on slotted ALOHA with successive interference cancellation(SIC) has been evaluated and tested by taking into consideration the performance of underlying physical layer. The performance of slotted ALOHA-SIC and the already existing carrier sense multiple access with collision avoidance (CSMA/CA) scheme with respect to channel access delay and average packet loss ratio is also studied

Wavelet based image compression integrating error protection via arithmetic coding with forbidden symbol and map metric sequential decoding with ARQ retransmission

The phenomenal growth of digital multimedia applications has forced the communication