In this letter, signal-to-noise ratio (SNR) performance is analyzed for orthogonal frequency division multiplexing (OFDM) based amplify-and-forward (AF) relay systems in the presence of carrier frequency offset (CFO) for fading channels. The SNR expression is derived under one-relay-node scenario, and is further extended to multiple-relaynode scenario. Analytical results show that the SNR is qu...

We present an improved line search method of the carrier frequency offset (CFO) estimate technique for OFDM systems aided with pilots. Unlike the conventional approaches, prior knowledge of channel order is unnecessary for the presented scheme, because we apply an interpolation technique for obtaining the extended channel frequency response. The search mechanism of the proposed approach is prim...

Orthogonal frequency division multiplexing (OFDM) is very sensitive to frequency errors caused by frequency differences between transmitter and receiver local oscillators. In this paper, this sensitivity is analyzed in terms of the complex weighting coefficients which give the contribution of each transmitter subcarrier to each demodulated subcarrier. Previously described windowing and self-int...

Broadband wireless systems generally use orthogonal frequency division multiplexing (OFDM) with link adaptation (LA) to achieve high throughput while meeting bit error rate (BER) constraint. OFDM systems are known to be affected by non-linearity of high power amplifier (HPA) at transmitter, carrier frequency offset (CFO), symbol timing offset (STO) and channel estimation error at the receiver. ...

A serious disadvantage of orthogonal frequency-division multiplexing (OFDM) is its sensitivity to carrier frequency offset (CFO) and timing offset (TO). For many low-complexity algorithms, the estimation ambiguity exists when the CFO is greater than one or two subcarrier spacing, and the estimated TO is also prone to exceeding the ISI-free interval within the cyclic prefix (CP). This paper pres...

The effect of spectrum sensing errors on the performance of orthogonal frequency division multiplexing based cognitive radio transmission can be evaluated by deriving the expression for the average bit error rate. This depends on various parameters like transmission and spectrum sensing parameters. Here, we consider the case with adding a carrier frequency offset. The spectrum sensing errors of...

Among the multicarrier modulation techniques considered as an alternative to orthogonal frequency division multiplexing (OFDM) for future wireless networks, a derivative of OFDM based on offset quadrature amplitude modulation (OFDM/OQAM) has received considerable attention. In this paper, we propose an improved joint estimation method for carrier frequency offset, sampling time offset, and chan...

The combination of Multiple-Input Multipleoutput (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) has been viewed as the trend of the new wireless LAN technology. In this paper, the design of an up-to-date 2 x 2 Space-Time Block Coded (STBC) MIMOOFDM baseband receiver is presented with reference to an IEEE 802.11 n proposal. To solve possible different carrier frequency offsets betw...

Wavelet Packet based Multi-Carrier Modulation (WPMCM) offers an alternative to the well-established OFDM as an efficient multicarrier modulation technique. It has strong advantage of being a generic transmission scheme whose actual characteristics can be widely customized to fulfill several requirements and constraints of an advanced communication systems. However, a few research questions rema...

In this paper, we give an overview of the sensitivity of a number of multicarrier systems to carrier and clock synchronization errors. A comparison is made between orthogonal frequency division multiplexing/multiple access (OFDM(A)) and two combinations of the orthogonal multicarrier technique and the code-division multiple access (CDMA) technique, i.e., multicarrier CDMA (MC-CDMA), where the s...