Fading

RAKE RECEIVER METHOD OF MULTIPATH FADING REDUCTION S.D Dayo1, K.O Egbo2, 1Department of Electrical and Electronics Engineering Ladoke Akintola University of Technology, Ogbomosho. 2 Department of Physics, Federal University of Technology, Owerri, Imo State ABSTRACT Wireless communications is, by any measure, the fastest growing segment of the communications industry. It has captured the attention of the media and the imagination of the public. However, the fundamental phenomenon which makes transmission

Error Performance improvement in Spatially Multiplexed MIMO Systems over Weibull-Gamma Fading Channel Keerti Tiwari and Davinder S. Saini Department of Electronics and Communication Engineering Jaypee University of Information Technology Waknaghat, Solan, (H.P.) - 173234, India E-mail- keerti.tiwari@mail.juit.ac.in, davinder.saini@juit.ac.in Abstract- In multiple-input multiple-output (MIMO) systems, spatial demultiplexing at the receiver is a motivational task. Thus, several detection techniques

Cooperative communication is a new concept of research and it is a powerful technique to mitigate fading in wireless relaying layout. Concerning with the fading problem, this paper is focuses to give a better non-orthogonal space-time block code (STBC) scheme and assimilate it in the cooperative relaying nodes for upgrading performance of the system. Golden coded has also been incorporated in IEEE 802.16 (Wi-MAX) standard as a full rate full diversity space-time code and proven to present a ranking

The wireless channel is different and much more unpredictable than the wire line channel because of factors such as multipath and shadow fading, Doppler shift, and time dispersion or delay spread. These factors are all related to variability introduced by mobility of the user and the wide range of environmental conditions that are encountered as a result. (i) Multipath Delay Spread The multipath delay spread is the time dispersion characteristic of the channel. Each multipath component is typically

narrow bandwidth compared to wideband channel in single carrier systems and also the symbol period on each subchannel is increased. Multicarrier modulation provides immunity to fading caused by data transmission over mul-tipath fading channels or frequency- selective fading channels. Each of the subchannel expe-riences flat fading due to the decreased bandwidth. Also, due to the increase in the symbol period, it provides enhanced immunity to ISI. Another advantage of multicarrier modulation technique

The Art of Fading Since we are drawn towards human figures, we first acknowledge that the woman is bone thin because this image is predicted to be after WWII, it explains the reason behind her external and internal fatigue. A hidden meaning is revealed that even though America won the war, others still suffer. Her body language portrays an undying need to reach what she perceives as fortification. Noticeably, by her torso twisting in an aberrant manner, portrays the fact that she is on a mission

of subcarriers will be affected and transmission would be possible in that case also. Immune to Frequency Selective Fading:- OFDM is highly immune to frequency selective fading channel as parallel transmission as each sub-carrier has narrow bandwidth in comparison to overall bandwidth of signal. Hence it converts a frequency selective fading channel into several nearly flat fading channels. High Spectral Efficiency:- Due to orthogonal nature of each sub-carrier, large number of subcarriers can

exactly one frequency, and the carrier frequency is modulated by random phase jitter [2]. The phase noise introduced results in a mismatch of frequencies between the local oscillators at the transmitter and the receiver. In addition, Doppler effects in fading channel also causes frequency offsets at the receiving carrier. As a result, the numbers of subcarriers cycles within the FFT period are not integers anymore, and the orthogonality property between subcarriers is not kept, causing ICI for an OFDM

access to passengers with high quality of service (QoS) is a key role in attracting more travellers [3]. Wireless communication systems to provide internet access for HSR are facing a lot of challenges such as, time varying and frequency selective fading due to multipath propagation and Doppler shift effect [4], a high penetration loss of 10-40 dB depending on the type of train and the angle of incidence resulting in spotty coverage and dropped calls [5], frequent handover due to the train high motion

MMSE-OSIC detection is used which gives reduced error rate compared to traditional MMSE with a considerable level of complexity. The system performance is analyzed in a composite fading environment which deals with multipath and shadowing, known as Weibull-gamma (WG) fading environment. Along with the composite fading, a composite noise i.e. additive white generalized Gaussian noise (AWGGN) model is taken into account to form various noise scenarios such as impulsive, Gamma, Laplacian, Gaussian