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In this paper, we propose and study a cooperative transmission scheme for amplify-and-forward (AF) relaying system with adaptive modulation. Unlike the conventional incremental relaying with adaptive modulation (IR-AM) scheme, which improves the spectral efficiency with the minimum usage of relaying, our proposed scheme adaptively utilizes cooperative relaying to maximize the system spectral efficiency...
In this paper we propose the idea of Phase-Superposition-Phase-Forward (PSPF) relaying for 2-way 3-phase cooperative network involving constant envelop modulation with discriminator detection in a time-selective Rayleigh fading environment. A semi-analytical expression for the bit-error-rate (BER) of the system is derived and comparison with one-way relay is made. Preliminary results indicate that...
In this paper we propose a novel connection admission control scheme named Rate Transition Area assisted Guaranteed Handover Scheme (GHS-RTA), which utilizes the geographical information, rate transition areas and overlap areas to intelligently decide when to block a new call. This scheme helps avoid possible inter-cell and intra-cell handover failures for HAP communications systems with adaptive...
We propose a cooperative transmission scheme for two users with one common relay using superposition modulation. It uses distributed Turbo codes (DTCs) for each user. The relay always decodes, then interleaves and re-encodes the decoded data. A new packet is formed by combining the re-encoded packets from both users using superposition modulation. This packet is forwarded to the destination with the...
In an orthogonal frequency division multiple access (OFDMA) system such as LTE and WiMAX, EESM provides an efficient way to estimate the link performance of a resource block/sub-channel contains a number of sub-carriers by a single value (effective SNR). In order to learn the performance of an OFDMA system involving EESM, it is of interest to investigate the statistics of effective SNR over frequency...
In this paper, we study retransmission strategies for the symmetric relaying scenario when the number of retransmissions for a data packet is limited. We propose a retransmission scheme based on superposition modulation and give the exact packet drop probability expression for it when only one retransmission is allowed. We compare the performance of the proposed retransmission scheme with retransmission...
There are few analytical formulas that can be used for calculating the block error rate (BLER) in block fading channels. Thus, an estimate of the BLER is often obtained using numerical methods. One such method is the threshold method which assigns 0 or 1 to the instantaneous BLER given the signal to noise ratio (SNR) level. It has been shown that utilizing such a method results in an accurate approximation...
The performance of multi-hop multiple-input, multiple-output (MIMO) communication scenarios is evaluated for space time block coded (STBC) and the proposed distributed cyclic delay diversity (CDD) technique. By increasing the frequency selectivity, multi-stage CDD with low complexity implementation yields significant performance improvement as relaying network. Both diversity techniques based on frequency-correlated...
In this paper, a joint channel-network coding is proposed for the multiple access half duplex relay channel. To improve performance, the classical constraints of orthogonality between links are partially relaxed, i.e., in the first transmission phase the two sources are allowed to transmit simultaneously, while in the second phase, the relay transmits alone and the sources are silent. In order to...
The pressure of the energy bill from operators and the request of the environmental protection from the governments and publics results in more urgent requirement on the energy consumption and CO2 emission. Traditionally, adaptive modulation has been proven to be an efficient solution to improve the system performance over the radio fading channels. To obtain the design insights for energy efficient...
In this paper, a novel method called offset modulation (OM-OFDM) is proposed, to control the peak-to-average power ratio of an OFDM signal. The theoretical bandwidth occupancy of the proposed offset modulated signal is derived. Using this bandwidth occupancy a closed form theoretical bit error rate (BER) expression for an offset modulated transmission is further derived, validated and compared to...
We derive in this paper the bit error probability and cutoff rate of an Amplify-and-Forward (AF) relay system operating in Rayleigh fast fading. In our model, we consider the relay thermal noise to be non-negligible and derive a closed form expression to approximate the bit error probability. Our approximated closed form expression matches well with simulation result. Using Chernoff bound, we upper...
Power Line Communications (PLC) are usually subject to severe degradations, partly due to the channel time dispersion. OFDM is a widely used multicarrier modulation scheme (MCM) for such frequency selective channels, because of the simplicity of the required equalization, and also because of its robustness toward Inter Symbol Interference (ISI), thanks to Cyclic Prefix (CP) insertion. However, other...
The envelope pulse-width modulation (EPWM) transmitter has been proposed to address the issue of low power efficiency in the linear amplification of multicarrier signals such as the OFDM. However, the delta-sigma (Σ-Δ) modulator in the EPWM transmitter generates quantization noise that degrades signal quality. In this paper, two new EPWM architectures called the envelope subtraction EPWM (ES-EPWM)...
This paper summarizes some key features for future Chinese digital television terrestrial broadcasting (DTTB) systems including improved frame structure, transmit diversity, advanced channel coding and modulation, multi-service support, broadcasting return channel solution and etc.
In this contribution, we propose a novel Distributed Source-coding, Channel-coding and Modulation (DSCM) scheme for cooperative communications. The proposed DSCM scheme is designed for ensuring the decoding convergence of its constituent component codes, namely, the Variable Length Code (VLC) and two Coded Modulation (CM) schemes. The source node encodes the source symbols with the aid of a serially-concatenated...
In this paper the performance of bit-interleaved coded modulation with iterative decoding (BICM-ID) based multiple-relay cooperative system is analyzed over Nakagami-$m$ fading channels. The relays are operating in amplify-and-forward (AF) mode. The moment generating function (MGF) based approach is used to obtain the theoretical error-free feedback (EF) bounds. The results show that a significant...
This paper presents an overview of system-level solutions for green wireless communication infrastructure. It illustrates that a combination of high efficiency amplification system with a linearity restoration technique is unavoidable. Currently, Doherty power amplifiers along with digital predistortion technique are able to achieve high power efficiency. However, due to the limited bandwidth of digital...
The International Telecommunications Union established through the International Mobile Telecommunications-Advanced a set of requirements for high performance 4rd Generation communication systems and, with the aim of meeting such requirements, 3rd Generation Partnership Project Long Term Evolution (LTE) is considering a set of enhancements, referred to as LTE-Advanced. In LTE-Advanced context, Coordinated...
This paper proposes a novel multi-dimensional modulation (MDM) scheme that achieves better performance than conventional modulation without any diversity or coding gain. We exploit the additional degrees of freedom offered by higher dimensional Euclidean space to construct the proposed constellation design. Analytical results are obtained for the exact symbol and bit error performance of the MDM design...
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