An algorithm for harmonic decomposition of time-variant signals is derived from a least squares harmonic (LSH) technique. The estimates of harmonic amplitudes and phases are formulated as the solution of a set of linear equations which minimizing mean square error; the signal frequency is modeled by a linear or quadratic polynomial and obtained via a local search over polynomial coefficients. A...

—Orthogonal Frequency Division Multiplexing (OFDM) has been a popular scheme for digital communication systems, which is widely used in digital television and audio broadcasting, wireless networks, powerline networks, and the Fourth Generation (4G) mobile communications. In OFDM scheme, channel estimation is a necessary technique for improving the system’s performance. Linear Least Square (LLS...

3rd generation partnership project (3GPP) long term evolution (LTE) uses single carrier-frequency division multiple access (SC-FDMA) in uplink transmission and orthogonal frequency division multiple access (OFDMA) scheme for the downlink. One of the most important challenges for a transceiver design is channel estimation (CE) and equalization. In this paper, a training based least mean square (...

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...

This paper presents a combined approach to channel estimation for multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM). It uses both time domain and frequency domain information in the received signal to estimate the channel. Initial estimate of the channel is obtained using pilot assisted least square (LS) channel estimation. The estimate is further enhanced ...

one of the most valuable and important application of artificial satellites in geodetic sciences is recovery of the earth's gravity field. orbits of satellites either gravimetric or nongravimetric are analyzed to improve the earth's gravity field. gravimetric satellites are launched at low altitudes to observe gravity field in more detail. grace twin satellites are the second spacecra...

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 ...