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Scheduling is a fundamental component in resource (bandwidth and power) management in NG wireless networks and plays the main role in providing QoS requirements such as delay, throughput and packet loss for different classes of service in 802.16d networks. In this paper we propose a novel scheduling algorithm Strict Priority Based Adaptive modulation and Coding (SP_AMC_Based) that can grantee QoS...
This paper gives an analysis about OFDM based WiMAX 802.16e with optimum training symbols. In further, performance is evaluated by considering the variable Delay Spread, Frequency Diversity, and with different Adaptive Modulation and Coding. The evaluation of system is performed over simulations showing, Packet error ratio [PER] versus mean Eb/No with Rayleigh fading. The system is considered with...
In this paper, we introduce a new satellite radio interface technology to provide efficient IMT-Advanced services. Maximizing the commonalities with the terrestrial system is one of the most important factors for cost-effective service delivery, which will finally bring successful deployment of the system. For this purpose, we adopt an OFDM based radio interface. At the same time, the interface should...
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...
Modern wireless communication demands reliable data communication at high throughput in severe channel conditions like narrowband interference, frequency selective fading due to multipath and attenuation of high frequencies. Traditional single carrier systems address this set of problems by the use of complex, computationally intensive equalization filters. The Orthogonal Frequency Division Multiplexing...
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...
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 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...
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...
Future wireless communication systems being characterized by tight frequency reuse, adaptive modulation and coding schemes and diversified data services will be interference limited by interfering signals of diverse rates and strengths. Keeping in view such a scenario, we propose in this paper the application of a proposed low complexity match filter (MF) based detector for spatial interference cancellation...
In accordance with the channel status information, modulation and coding method can be changed adaptively to enhance the throughput in Long Term Evolution Time Division Duplexing (LTE TDD) system. With the scheme of Exponential Effective SNR Mapping (EESM) and Mutual Information Effective SNR Mapping (MIESM), two Adaptive modulation and coding mechanisms are proposed in this paper. Simulation results...
This paper presents a joint adaptive modulation and coding (AMC) scheme, which exploits the coherence bandwidth of the wireless channel to divide the transmitted frame into independent sub-channels that correspond to the channel coherence bandwidth. This strategy is implemented for orthogonal frequency division multiplexing (OFDM) systems with channel state information (CSI) feedback. Low density...
In this paper, we have carried out a detailed analysis of IEEE 802.16-2004 256-point FFT OFDM PHY layer and also simulated the important features of the PHY layer to have a better understanding of the standard. Our main objective is to analyze, evaluate and compare the performance of the PHY layer under various AMC (Adaptive modulation and coding) modes and channel conditions. The discussions based...
This paper presents an adaptive codebook design method, which introduces a transition probability based codeword sorting scheme in an effort to reduce the feedback overhead by exploiting the temporal correlation of the channel. The adaptive codebook sorts the codewords in the increasing order of the chordal distance with respect to the initial codeword, which is the codeword chosen at the previous...
The system model and the algorithm for a cross-layer design combining the adaptive modulation and coding with ARQ based on frequency domain subcarrier of OFDM is developed at first. And then the effect of high speed move to the performance of that is analyzed. In order to compensate the degraded performance of wireless link due to high-speed move, a novel finite-state Markov channel model is formed...
An precise but simple link quality model is crucial to improve the accuracy and flexibility of link adaptation design of LDPC coded OFDM system, because it acts as a link-to-system interface which provides system simulator immediately the BLER performance of a certain modulation and coding scheme corresponding to the current SINR states, which is an instantaneous vector. This contribution extends...
In this paper, we study bandwidth management of a wireless/optical based access/metro network in support of voice and data services. For voice services, we use a finite state Markov Chain to estimate the blocking probability of voice circuits over an Adaptive modulation and coding wireless channel, as a function of the channel parameters. For data services, we evaluate a rate matching and a buffer...
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