Adaptive modulation and coding (AMC) and Multicode transmission are to achieve higher rate to fit fast fading channel. Considering these two technologies together is a challenge problem. In this paper, we develop the ...
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ISBN:
(纸本)9781424408009
Adaptive modulation and coding (AMC) and Multicode transmission are to achieve higher rate to fit fast fading channel. Considering these two technologies together is a challenge problem. In this paper, we develop the existing algorithm in[l] to provide better performance under multipath environment, furthermore, we realign all the schemes in order to use the threshold mapping. Simulation results show the noticeable improvement.
This paper analyzes the characteristics of the satellite communication system as well as the satellite communication channel and introduces the basic principles and outstanding advantages of convolutional code and MSK...
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ISBN:
(纸本)9781424421923
This paper analyzes the characteristics of the satellite communication system as well as the satellite communication channel and introduces the basic principles and outstanding advantages of convolutional code and MSK *** combined implementation of properly chosen convolutional code and MSK modulation is a feasible scheme for the satellite communication with existing power limitation and all kinds of potential fading and noise. BER performance of convolutional code and MSK is simulated with Matlab/Simulink. The conclusions based on the simulation's results provide references to the design of the satellite communication system.
GSM/EDGE is the world's largest and most widespread cellular technology. EDGE offers an attractive solution for 3 rd generation cellular services in existing GSM networks. The introduction of new services into an...
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GSM/EDGE is the world's largest and most widespread cellular technology. EDGE offers an attractive solution for 3 rd generation cellular services in existing GSM networks. The introduction of new services into an existing network typically leads to increased capacity demands, since more users of different service types need to coexist in limited spectrum, while the existing speech service is required to function at least as well as before. Higher Order modulation in combination with Turbo coding is proposed to substantially enhance spectrum efficiency and average user bit rates in GSM/EDGE through improved interference robustness and increased peak bit rates. Simulation results indicate link level gains of 2.5-5.5 dB. When additionally applying incremental redundancy, similar relative improvements are shown. Bit rates can be increased by more than 30%, at C/I levels above 30dB. System performance gains are indicated by average user bit rate enhancements of up to 30-40%, along with substantial gains in spectrum efficiency, up to 40%. It is also shown that system gains are rather insensitive to frequency reuse and whether frequency hopping is applied or not (in sparse reuse scenarios).
A cross-layer design is developed for quality-of-service (QoS) guaranteed traffic. The proposed design jointly exploits the error-correcting capability of the truncated automatic repeat request (ARQ) protocol at the d...
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A cross-layer design is developed for quality-of-service (QoS) guaranteed traffic. The proposed design jointly exploits the error-correcting capability of the truncated automatic repeat request (ARQ) protocol at the data link layer and the adaptation ability of the adaptive modulation and coding (AMC) scheme at the physical layer to optimize the system performance. The queuing behavior induced by both the truncated ARQ protocol and the AMC scheme is analyzed with an embedded Markov chain. Analytical expressions for performance metrics such as packet loss rate, throughput and average packet delay are derived. Using these expressions, a constrained optimization problem is solved numerically to jointly determine the retry limit for the truncated ARQ protocol as well as the prescribed packet error rate for the AMC scheme so that the overall system throughput is maximized under the specified QoS constraints.
Due to the time variant characteristic of wireless communication channels, channel-state-information (CSI) becomes out-of-date if we consider the CSI feedback delay. Thus, channel prediction is required to mitigate th...
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Due to the time variant characteristic of wireless communication channels, channel-state-information (CSI) becomes out-of-date if we consider the CSI feedback delay. Thus, channel prediction is required to mitigate this phenomenon. In this paper, we propose an adaptive modulation and coding (AMC) scheme using channel prediction on multipath Rayleigh fading channels and evaluate the performance of the proposed scheme. For a given modulation and coding set (MCS), the average packet error rates are derived as functions of the predicted channel information and the prediction error variance. Based on CSI's, the required transmit power is obtained for each MCS option, simulation results show that the performance degradation due to feedback delay can be compensated by the proposed scheme
Bit interleaved coded multiple beamforming (BICMB) was previously designed to achieve full spatial multiplexing of min(N, M) and full spatial diversity of NM for N transmit and M receive antennas over flat fading chan...
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Bit interleaved coded multiple beamforming (BICMB) was previously designed to achieve full spatial multiplexing of min(N, M) and full spatial diversity of NM for N transmit and M receive antennas over flat fading channels. Furthermore, BICMB when combined with orthogonal frequency division multiplexing (OFDM) achieves full spatial multiplexing and full diversity order of NML over L-tap frequency-selective channels. BICMB requires full channel state information (CSI) both at the transmitter and receiver, however it uses uniform power and rate over the parallel channels established by multiple beamforming. In this paper, our main goal is to investigate the performance of the previously analyzed BICMB system via adaptive modulation and coding (AMC) to further utilize CSI and to improve system throughput performance. Hence, we name the new systems as adaptive BICMB (ABICMB) over flat fading, and ABICMB-OFDM over frequency-selective channels. Simulation results show that adaptive system achieves 4-13 dB performance gain compared to non-adaptive case depending on the antenna configuration and environment. Systems analyzed require perfect CSI both at the transmitter and receiver, which may be difficult to obtain in a practical scenario. However, high performance gains achieved makes it worthwhile to study the performance of the proposed systems, leaving room for significant gain with limited feedback
In this paper, we propose two adaptive schemes where either the modulation mode or the space-time block code (STBC) pattern is changed for a space-time coded system with transmit antenna selection. Simulation results ...
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In this paper, we propose two adaptive schemes where either the modulation mode or the space-time block code (STBC) pattern is changed for a space-time coded system with transmit antenna selection. Simulation results show that the improvements in terms of capacity, data throughput and BER can be obtained over the nonadaptive schemes
The challenge for broadband fixed wireless access (BFWA) systems, which represent an attractive solution for broadband access in the last mile and for wireless backhauling applications in the "middle mile", ...
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The challenge for broadband fixed wireless access (BFWA) systems, which represent an attractive solution for broadband access in the last mile and for wireless backhauling applications in the "middle mile", lies in providing high data rates and quality of service (QoS). Such requirements mainly derive from the need to provide new bandwidth consuming multimedia services and applications, efficient handling of IP traffic, effective use of the limited radio spectrum and a greater backhaul capacity to support the increased number of users per cell site. IEEE 802.16 family of standards and its associated consortium WiMAX are gaining more and more interest in the telecommunication areas as broadband fixed wireless access solution with possible extension in nomadic and mobile area. Its main leverages are an efficient handling of IP traffic, the support of channel adaptivity and advanced QoS management. This paper aims at defining a new packet-based scheduling strategy for an IEEE 802.16 system supporting variable length MAC protocol data units (PDUs) and adaptive coding and modulation while fulfilling QoS requirements. A performance analysis of the proposed scheduler is presented and discussed in terms of packet transfer delay, MAC overhead and average throughput
Adaptive modulation and coding (AMC) has gained a lot of attention in the research of high speed downlink packet access (HSDPA). The idea is to adapt the transmission to the fast changing channel conditions by the use...
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Adaptive modulation and coding (AMC) has gained a lot of attention in the research of high speed downlink packet access (HSDPA). The idea is to adapt the transmission to the fast changing channel conditions by the use of different modulation and coding schemes (MCS). In this paper, an adaptive algorithm (ITA) is presented for the AMC technique in HSDPA and a theoretical analysis model is introduced to investigate the throughput and FER of ITA. Subject to the given FER target, the numerical and link level simulation results both show that ITA outperforms the adaptive algorithms
In this report, a new technology of adaptive modulation and coding is proposed. This technique is designed for a cognitive radio system. The proposed technique is implemented into an ultra high speed wireless system. ...
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In this report, a new technology of adaptive modulation and coding is proposed. This technique is designed for a cognitive radio system. The proposed technique is implemented into an ultra high speed wireless system. The system has maximum 400 Mbps throughput with 80 MHz bandwidth. It is considered as an expanded model of the standard systems on IEEE 802.11a and 802.11n. When the throughput becomes high such as our designed wireless system, it is not easy to keep its throughput high enough under various circumstances. In order to obtain the optimum throughput under these circumstances, the proposed technique determines adaptively the specification of modulation and coding where several specifications of modulation can be designed and can be adaptively selected in our system. This report presents its evaluation of our proposed techniques. It is shown that the optimum condition is usually obtained in our system
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