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We consider serial concatenation of a Luby Transform (LT) code with a differential quadrature phase-shift-keying (DQPSK) modulator for transmission over an additive white Gaussian noise (AWGN) Channel. Assuming a target average rate for the operation of the rateless LT DQPSK scheme, the degree distribution of the LT code is optimized in terms of convergence threshold using extrinsic information transfer...
A PHY-MAC cross layer design is proposed which optimizes the target packet error rate (PER) and maximizes the throughput. In doing so, an adaptive modulation and coding (AMC) scheme with 3 different transmission modes is chosen which are available in IEEE 802.11a Standard. A general analytical procedure to investigate the performance for transmissions over the wireless link is developed where finite...
Emerging 4G standards, such as WiMAX, LTE, and TD-SCDMA, have adopted the proven technique of Adaptive Modulation and Coding (AMC) to dynamically react to channel fluctuations while maintaining bit- error rate targets of the transmission. To mitigate the vicious effects due to stale channel state indication (CSI) problem, this paper introduces a novel framework by incorporating AMC with layered transmission...
For time-division multiplexed satellite communications links, a multi-rate waveform can enable substantial capacity gains over waveforms employing static coding and modulation. Using a multi-rate waveform such as DVB-S2 with adaptive coding and modulation (ACM), a user's data is transported with the most efficient modulation and forward error correction coding point that specific user can reliably...
Scalable video coding (SVC), together with adaptive modulation and coding (AMC), can improve wireless multicast streaming video by jointly performing radio resource allocation and modulation and coding scheme (MCS) selection. However, the existing schemes in the literature allocate radio resources for different video layers separately, which leads to a waste of radio resources. In this work, we introduce...
Dual feedback control algorithm has proved to allow the base station to respond quickly and efficiently to the uplink bandwidth request in broadband wireless access (BWA) networks. In this algorithm the bandwidth request is calculated based on both the length of the backlogged queue and the mismatch between packet arrival and service rates. However, the physical channel quality, SNR, does not play...
Dimensioning the mobile link for aeronautical communications between aircraft and the satellite is a critical issue due to the limited power available, in particular if an omnidirectional antenna is used on board the aircraft. Also there are large channel variations due to the different effects occurring on the L-band mobile link and over-dimensioning of the user terminal or satellite should be avoided...
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...
Adaptive modulation and coding (AMC) is attracting research interest in wireless multicast broadcast services (MBS). AMC increases the system throughput by utilizing possible good channel states instead of using robust modulation and coding schemes. A model for the AMC in an MBS system with multiple MBS groups is provided, and stochastic analysis using Markov chain is also applied for modeling analysis...
Quality of service (QoS) differentiation is one of the keys to success for WiMAX (Worldwide Interoperability for Microwave Access) networks. Although the IEEE 802.16 standard issued some guidelines to design a QoS architecture, for the most part implementation details are left to manufacturers. Focus in this paper is on channel-aware scheduling policies to be implemented in the WiMAX Base Station...
This paper develops cross-layer adaptive modulation and coding as an efficient method for bit interleaved coded OFDM packet transmission. As objective function, we adopt the goodput, or the number of data bits delivered without error per unit of time. After the formalization of the optimization problem through an accurate modeling on the link performance, an iterative solution is derived based on...
A conventional OFDM system often poses a stringent linearity requirement to the transmitter, especially the radio-frequency power amplifier (RFPA), to maintain its bit error rate (BER). As a result, the output power from a RFPA is often limited, thus, the communication distance is compromised. With the deployment of WiMAX (IEEE 802.16), which is targeting at the mobile market, the communication distance...
In this paper the spectral efficiency using combinations of Transmit Antenna Selection with Linear Dispersion Code Selection (TACS) is studied. The selection criterion is defined in order to maximize the spectral efficiency while bounding the maximum error rate (Rate Adaptation). The performance of the proposed spatial link adaptation scheme is evaluated under low mobility environments concluding...
The downlink of the Long Term Evolution (LTE) would be OFDMA based and combination of Hybrid ARQ at the data link layer with adaptive modulation and coding (AMC) at the physical layer might be employed. Constellation rearrangement (CR) technique is used in HARQ to enhance MQAM performance. An improved mapping method is used in full IR to enhance system performance. An improved SNR estimation algorithm...
In this paper, we propose an efficient semi-analytical throughput evaluation strategy for an orthogonal frequency division multiple access (OFDMA) system. We compare the performance of the simulated and semi-analytical throughput values in terms of average signal to noise ratio (SNR). In the investigated system, OFDMA is combined with adaptive modulation and coding (AMC) technique based on distinct...
We consider a link adaptation scheme with adaptive coding and modulation and adaptive retransmissions on a block fading channel. Therefore, we characterize the performance of the employed channel code with puncturing and repetition coding in a unified way and use this description to devise a method to adapt modulation and code rate in the initial transmission as well as in all retransmissions. We...
In this paper, we study the performance of an Orthogonal Frequency Division Multiplexing (OFDM) WiMAX transmission system with adaptive modulation and coding (AMC) over different fading channels. An explanation necessary to understand the block diagram of the system is briefly given and a MATLAB code is written to simulate the basic processing involved in this system. The simulation is performed for...
The effects of adaptive-rate transmissions and routing on the total throughput of a slow-frequency-hop packet-radio network are considered. Adaptive rates are achieved through the use of error-control coding with perfect side information. Both fixed-length codes and variable-length codes are considered. Performance results are obtained for direct transmission (i.e., no routing), two-hop limited routing,...
There are a few core technologies to enable high-performance 4th generation (4G) broadband wireless communication system. A multiple input multiple output (MIMO) provides high-rate transmission through expended channels by multiple array antennas in both sender and receiver side. Also orthogonal frequency division multiplexing (OFDM) is well-known as the most appropriate technique for high data rate...
Resource allocation (RA) is a crucial task in the operation of wireless communication systems, which in many cases aims at meeting the users' quality of service (QoS) requirements with the minimum amount of resources. In this work, we consider the QoS-provisioning RA problem at the downlink of a multicarrier system, where the total transmit power consumption is to be minimized. Two RA schemes, one...
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