The future wireless network demands higher-level modulation to enhance spectral efficiency, which means a symbol-to-bit soft demapper with much higher complexity is required if using conventional demapping algorithm. In this paper, we proposed low-complexity for 256 QAM. Simulations show that it achieves lower the negligible performance degradation in comparison max-log-MAP demapper.

Discrete cosine transform (DCT) based orthogonal frequency-division multiplexing (OFDM), which has double the number of subcarriers compared to classic discrete Fourier (DFT) OFDM (DFT-OFDM) at same bandwidth, is a promising high spectral efficiency multicarrier technique for future wireless communications. In this paper, an enhanced DCT-OFDM with index modulation (IM) (EDCT-OFDM-IM) proposed further exploit benefits and IM techniques. To be more specific, pre-filtering method DCT-OFDM-IM...

Orthogonal frequency division multiplexing (OFDM-IM) is a multicarrier transmission technology that modulates information bits not just onto subcarriers by means of M-ary constellation mapping but also selected (active) subcarrier indices. Consequently, errors can occur in OFDM-IM systems indices addition to the symbols. This paper analyzes error scenarios and derives mathematical expressions for performance based on maximum likelihood (ML) detection. In evaluating bit rate (BER) additive...

This paper presents a novel method to estimate the frequency offset between mobile phone and infrastructure when initially attaches LTE network. The proposed scheme is based on PRACH (Physical Random Access Channel) preambles can significantly reduce complexity of preamble detection at eNodeB side.

Regarded as one of the most promising transmission techniques for future wireless communications, discrete cosine transform (DCT)-based multicarrier modulation (MCM) system employs basis orthogonal functions real-modulated symbols multiplexing, by which minimum frequency spacing can be reduced half compared with Fourier transform-based one. With a time-reversed pre-filter employed at front receiver, interference-free one-tap equalization is achievable DCT-based systems. However, due to...

Several techniques such as carrier aggregation (CA) and cognitive radio (CR) have been proposed to achieve high data rates meet the demand of future wireless communication systems. Those pose a strict adjacent channel interference (ACI) requirement. However, currently employed orthogonal frequency division multiplexing (OFDM) systems suffer from significant spectrum leakage require large guard bands avoid ACI. To tackle this problem, there is need explore new suitable multicarrier modulation...

Orthogonal frequency division multiplexing (OFDM) with index modulation (IM) (OFDM-IM), which employs the activated sub-carrier indices to convey information, exhibits higher energy efficiency and lower peak-to-average power ratio (PAPR) than conventional OFDM systems. To further improve throughput of discrete Fourier transform (DFT) based OFDM-IM (DFT-OFDM-IM), cosine (DCT) (DCT-OFDM-IM) can be employed double subcarriers given same bandwidth. However, one main disadvantage DCT-OFDM-IM is...

The discrete cosine transform (DCT) based multicarrier system is regarded as one of the complementary transmission techniques for 5th Generation (5G) applications in near future. By employing basis orthogonal functions multiplexing each real-valued symbol with period T, it able to reduce minimum frequency spacing 1/(2T) Hz, which only half that compared Fourier (DFT) systems. Critical optimal DCT-based design achieves interference-free single-tap equalization, not both prefix and suffix are...

This paper presents an analysis on performance of ultra dense network (UDN) with and without cell cooperation from the perspective information theory. We propose a UDN metric called Total Average Geometry Throughput which is independent user distribution or scheduler etc. analyzed in detail for cooperation. The numerical results show that under studied system model, total average geometry throughput reaches its maximum when inter-cell distance around 6 ∼ 8 meters, both Cell can significantly...

In this letter, a novel supplementary index bit aided transmit diversity (SIB-TD) approach is proposed for an enhanced discrete cosine transform based orthogonal frequency division multiplexing with modulation (EDCT-OFDM-IM) system. Specifically, conventional (IM) employed the first antenna, i.e., main branch, and non-activated subcarriers' indices in one group are utilized IM mapping on same second branch. Hence, each subcarrier can not be synchronously activated two antennas. Finally,...

Carrier frequency offset estimation in Single Frequency Division Multiple Access (SC-FDMA) system is a challenging task. In this paper, novel method based on the pilot signal domain proposed. This algorithm does not require knowledge of channel, and only one symbol needed for estimation. These promising features will facilitate its deployment current systems without changing air-interface. A performance evaluation conducted over Demodulation Reference Signal Evolved Universal Terrestrial...

The discrete cosine transform (DCT) based multicarrier modulation (MCM) system is regarded as one of the promising transmission techniques for future wireless communications. By employing basis orthogonal functions multiplexing each real-valued symbol with period T, it able to maintain subcarrier orthogonality while reducing frequency spacing 1/(2T) Hz, which only half that compared Fourier (DFT) systems. In this paper, following effective models by zeros are inserted guard sequence and DCT...

Index modulation (IM) has recently emerged as a promising concept for spectrum and energy-efficient next generation wireless communications systems since it strikes good balance among error performance, complexity, spectral efficiency. IM technique, when applied to multicarrier waveforms, yields the ability convey information not only by M-ary signal constellations in conventional but also indexes of subcarriers, which are activated according incoming bit stream. Although is well studied...

The closed-loop adaptive space-time transmit diversity (ASTTD) scheme with real, non-binary weighting functions has been proposed for the 3GPP standardization. Predictive feedback quantization is used encoding of information (FBI) in ASTTD receiver and its regeneration (decoding) transmitter. FBI decoder transmitter consists an L-stage delay-line buffer storing a number L most recently received bits, look-up table amplitude weights that are selected by state buffer. In this paper, method...

An index modulation (IM) assisted Discrete Cosine Transform based Orthogonal Frequency Division Multiplexing (DCT-OFDM) with Enhanced Transmitter Design (termed as EDCT-OFDM-IM) is proposed. It amalgamates the concept of and Index Modulation to exploit design freedom provided by double number available subcarrier under same bandwidth. In proposed EDCT-OFDM-IM scheme, maximum likelihood (ML) detector used for symbol bits recovering derived sophisticated designing guidelines are provided....