Orthogonal Frequency Division Multiplexing (OFDM) is a well-known technique for the broadband wireless communication system. However, a main problem in OFDM is its vulnerability to frequency offset errors due to which the orthogonality is destroyed that result in Inter carrier Interference (ICI). ICI causes power leakage among subcarriers thus degrading the system performance. This paper studie...

In orthogonal frequency-division multiplexing (OFDM)based wireless local area networks (WLANs), phase noise (PHN) and residual frequency offset (RFO) can cause the common phase error (CPE) and the inter-carrier interferences (ICI), which seriously degrade the performance of systems. In this letter, we propose a combined pilot symbol assisted and decision-directed channel estimation scheme based...

In this paper, we present a new class of blind cyclic-based estimators for carrier frequency offset and symbol-timing error estimation of orthogonal frequency-division multiplexing (OFDM) systems. The proposed approach exploits the properties of the cyclic prefix subset to reveal the synchronization parameters in the likelihood function of the received vector. In this paper, a new likelihood fu...

A novel least-squares (LS) scheme to estimate the channel frequency response (CFR) for orthogonal frequency division multiplexing (OFDM) over slow fading channels is presented. We take the advantage of slow fading to use repeated OFDM training blocks. This not only can facilitate the LS formulation but also improve the channel estimation performance as compared to the conventional one block LS ...

Frequency-hopping (FH) methods in the Orthogonal frequency division multiplexing access(OFDMA) system,which are to assign user-specific subcarrier to the active users, have been paid much attention to in the broadband wireless communication system. In this paper, we present a novel multiple access scheme, referred to as CDM-FH-OFDMA, which is the extension of FH-OFDMA with code division multipl...

Orthogonal frequency division multiplexing (OFDM) combined with time division multiplexing (TDM), called OFDM/TDM, can overcome the high peak-to-average-power ratio (PAPR) problem of the conventional OFDM. Its bit error rate (BER) performance in a frequency-selective fading channel is improved by adoption of frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion...

Orthogonal frequency division multiplexing (OFDM) has developed into a popular scheme for wideband digital communications used in consumer applications such as digital broadcasting, wireless networking and broadband internet access. In the OFDM system, carrier frequency offset (CFO) causes intercarrier interference (ICI) which significantly degrades the system error performance. In this paper w...

Abstract – We present a method for the joint estimation of timing and carrier-frequency offset in Orthogonal frequency-division multiplexing (OFDM) systems. We show that it is possible to generate these estimates without the use of pilots, by exploiting the cyclic prefix of OFDM frames. We derive the joint likelihood function of the offsetparameters given the received data. The performance of t...

Abstract— Orthogonal frequency division multiplexing (OFDM) is an important technique to support high speed transmission of broadband traffic in wireless networks, especially broadband wireless local area networks (LANs). Based on OFDM, a new multiple access scheme, called OFDM-TDMA with subcarrier allocation (OFDMTDMA/SA), is introduced in this paper. It provides more flexibility in resource a...