Blind equalization in SIMO OFDM systems with frequency domain spreading

The problem of bandwidth efficient data transmission in multiple antenna or thogonal frequency division multiplex (OFDM) systems is considered. Contrar y to the mono-sensor systems, the effects of frequency-selective fading may be compensated in the multiple antenna systems due to the space diversity without using a wireless overhead. A modulation scheme that improves the re liability of data transmission in fading multipath environments and perform s an accurate channel equalization with no excess bandwidth neither substan tial training is proposed, The ne cv scheme exploits a frequency domain spr eading along with the standard OFDM modulation. This modulation yields an i mproved error rate; its structure is also exploited to estimate the equaliz er. The problem of reliable channel equalization in such systems is shown t o be essentially different in single and multiple antenna scenarios. For th e multiple antenna scenario, a new approach to to robust equalization is pr oposed, and its performance is analyzed. The numerical study confirms the e fficiency of the new method in such bandwidth-expensive applications as wir eless networks.