---Orthogonal Frequency Division Multiplexing (OFDM) has been recently applied widely in wireless communication systems, due to its high data rate, transmission capability with high bandwidth, efficiency and its robustness to multipath delay .Channel estimation is an essential problem in OFDM system. Pilot-aided channel estimation has been used; a good choice of the pilot pattern should match t...

In this paper, we investigate the system performance of a multi-cell multi-user (MU) hybrid millimeter wave (mmWave) multiple-input multiple-output (MIMO) network adopting the channel estimation algorithm proposed in [1] for channel estimation. Due to the reuse of orthogonal pilot symbols among different cells, the channel estimation is expected to be affected by pilot contamination, which is c...

Coherent detection in OFDM systems requires accurate channel state information (CSI) at the receiver. Channel estimation based on pilot-symbol-assisted transmissions provides a reliable way to obtain CSI. Use of pilot symbols for channel estimation, introduces overhead and it is desirable to keep the number of pilot symbols as minimum as possible. This paper introduces a new tight bound for the...

In recent years, spectral efficiency has become a key parameter in mobile radio communications. For Code Division Multiple Access systems, high spectral efficiencies can only be achieved by the application of multi-user detection schemes combatting the inherent multi-user interference. This paper analyzes the system performance of a quasi-synchronous OFDM-CDMA uplink for nonlinear successive in...

Totally blind APP channel estimation is based on the A Posteriori Probability (APP) calculation algorithm. Asymmetrical modulation schemes are used in order to resolve the phase ambiguity with no need for any pilot or reference symbols. In OFDM-systems, the two-dimensional channel estimation is performed by applying a concatenation of two one-dimensional APP estimators for frequency and time di...

An LDPC-coded FH-OFDMA system is proposed for the uplink of a packet-based cellular system, where the frequency hopping (FH) is based on a resource block (RB) for coherent demodulation. For the system, different RB types are employed either for better intercell interference (ICI) averaging capability or for better channel estimation performance. For the receiver, practical iterative channel est...

Based on frequency domain pilot channel estimation is a typical technology of channel estimation in OFDM system. In most cases, the pilot configuration of the system can’t start from the first subcarrier, which will have an effect on channel estimation values at the pilot, especially in the algorithm of channel estimation based on DFT interpolation which will largely degrade the performance of ...

This paper mathematically proposes channel estimation algorithms for Cognitive Radio (CR) in terms of Mean Square Error (MSE) and analysis of its Bit Error Rate (BER) performance. As cognitive radio associates itself with the family of opportunistic communication for using frequency spectrum efficiently, issues such as spectrum sensing and channel estimation gain attention. When the main issue ...

The ECMA-368 standard specifies multiband orthogonal frequency division multiplexing (MB-OFDM) as the definitive technology for high rate ultra-wideband (UWB) communications. Like other wireless systems, the performance of a correct data signals detection and decoding in MB-OFDM UWB is reduced by narrowband interference (NBI). A more specific problem of severity arises when interferences are pr...

---In this paper we present an improved and robust channel estimation algorithm for OFDM mobile communication systems based on the use of pilot subcarriers.Specifically we present an iterative channel estimation technique to improve the performance of channel estimators.In iterative receiver structures, soft information becomes available after the decoding stage. This information is used to enh...