A Study of Different Angles for the New Spread Matrix for BSOFDM in UWB Channels

Abstract

This paper presents a study into different angles for the New spread matrix developed for BSOFDM. It varies the angles for the matrix to develop different constellation schemes which are useful in overcoming the frequency selective channels which are encountered in mobile communication systems. Previously it has been discussed that this new matrix (the rotation matrix) has some advantages over Hadamard and the rotated Hadamard matrix in certain channels. This paper presents a study of varies angles with this new matrix over the UWB channels CM1 to CM4. Disciplines Physical Sciences and Mathematics Publication Details

A Study of Different Angles for Higher Order Rotation Spreading Matrix for BSOFDM in UWB Channels

“…Figure 3 depicts the constellation scatter plot of QPSK which will be used for this study. An interesting feature of this higher order Rotation spreading matrix is for angles such as α = π 4 , the modulation constellation no longer rotates on it self as it did with the case of block size M = 2 in [7]. As can be seen from Figure 10, it still increased the correlation between the transmitted symbols.…”

“…This is depicted in Figure 2. This paper continues the study of the Rotation spreading matrix presented in [1] and [7] and studies different angles for higher order block sizes. Below the description of the Rotation spreading matrix is presented and discussed in terms of the different possible combinations achievable for higher order block sizes such as M = 4.…”

“…In [1] a new matrix called the Rotation spreading matrix was introduced and in frequency selective channels such as the UWB channels it was shown to outperform other spreading matrices like the Hadamard which can be used in Block Spread OFDM (BSOFDM) and is discussed in detail in [2], [3], [4], [5] and [6]. In [7] it was experimentally shown for a block size of M = 2 the angle α = π 3 was shown in terms of BER to outperform other angles. But this is no longer the case for higher order Rotation spreading matrix discussed in [8].…”

Higher order rotation spreading matrix for block spread OFDM

“…Figure 3 depicts the new modulation scheme after the M = 2 sized blocks are multiplied by the new Rotation spread matrix U using α = π 3 . It was shown in [6] that the angle π 3 in UWB CM 1 channel achieved the better result, this can be seen in Figure 4 comparing three different angles.…”

Analytical Study of the Rotation Spreading Matrix of Block Spread OFDM with MMSE Equalization

“…The angle α is chosen depending on the system requirements and a simulation studies [2], [3], [4] and [5] comparing different angles performance can be seen in Figure 1, comparing angles for α = pi 6 , π 3 , π 7 in UWB channel CM 1 using N = 64 subcarriers and ML decoding.…”