The orthogonal frequency division multiplex (OFDM) transmission technique can efficiently deal with the effects of multi-path propagation in the broadband radio channel. It also has a high system inherent flexibility for designing a multiple access scheme by combining the conventional TDMA, FDMA and CDMA approaches with the OFDM modulation scheme. The FDMA multiple access scheme is especially i...

Power Line Communication (PLC) is predicted as a prospective solution for indoor and outdoor communications over power supplies. Broadband over Power Lines (BPL) uses a large bandwidth to provide high-speed Internet services to the end user. However, the channel exhibits high frequency selectivity and impulse noise, requesting modern signal processing methods. Orthogonal Frequency Division Mult...

In this paper, a low complexity and efficient multi-user Space Time Block Code Multi-Carrier Code Division Multiple Access (STBC MC-CDMA) for downlink wireless communication system is proposed. STBC MC-CDMA provides diversity gain to improve transmission efficiency of mobile wireless systems where both STBC encoder and decoder are in time domain thus reducing the complexity at the receiver side...

In this paper, we propose and evaluate a new algorithm to schedule multimedia data in a multi-user OFDM wireless system. This algorithm dynamically allocates the resource in both time and frequency domains based on feedback channel states, packet QoS requirements and the amount of data to be transmitted. Accordingly, maximum delay, BER requirement and priority of the packet are well met with im...

We study the performance of uplink transmission in a large-scale (massive) MIMO system, where all the transmitters have single antennas and the receiver (base station) has a large number of antennas. Specifically, we analyze achievable degrees of freedom of the system without assuming channel state information at the receiver. Also, we quantify the amount of power saving that is possible with i...

A compact two element MIMO (Multiple Input Multiple Output) system is proposed using a multi slot patch antenna employing polarization diversity. The proposed MIMO system offers improved bandwidth, return loss and isolation characteristics. The system resonates at 5.35GHz and 5.81GHz frequencies for VSWR≤2, which can be used for 4G & WiMAX applications. The simulation results of return loss, mu...

In this paper we present a novel technique for resource allocation in Multiuser Orthogonal Frequency Division Multiplexing (MU-OFDM) Systems with proportional rate constraint. The subcarrier allocation is tackled using a novel algorithm which combines the aspects of both deterministic and genetic algorithms (GA). For the calculated subcarrier allocation, bit-loading is done using the standard W...

Doppler scale estimation is one critical step needed by the resampling operation in acoustic communication receivers. In this paper, we compare different Doppler scale estimation methods using either cyclic-prefixed (CP) or zero-padded (ZP) orthogonal-frequency division-multiplexing (OFDM) waveforms. For a CP-OFDM preamble, a self-correlation method allows for blind Doppler scale estimation bas...

Orthogonal frequency division multiplexing (OFDM) is a popular technique to mitigate ISI caused by multipath fading effect of the radio channel. In practice, OFDM could be used in combination with space-time coding, which can be performed in a multiple-input multiple-output (MIMO) system, to increase the diversity gain and/or to enhance the system capacity over timevariant and frequency-selecti...