In this paper, we propose an indoor image sensor communication (ISC) system comprising an attentive indoor environment in which rolling-shutter cameras (including smart phone cameras) are used to receive data from lig...
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In this paper, we propose an indoor image sensor communication (ISC) system comprising an attentive indoor environment in which rolling-shutter cameras (including smart phone cameras) are used to receive data from light sources. The challenges of intended system mainly come from the receiver side, including its rolling shutter mechanism, its low and time-variant frame rate (e. g., no greater than 30 fps), and the narrow bandwidth response (i. e. several kHz baseband). Also, the requirements of flicker-free modulation enabling the dimming capacity, and indoor distance (i. e., up to 10 m) are unmitigated challenges. To resolve all mentioned challenges, we propose new hybrid modulationschemes, including M-ary frequency-shift keying (M-FSK) modulation and a hybrid modulation of M-FSK and phase-shift keying (2-PSK) for ISC. Simulation, numerical analysis and experiment results are given to illustrate the feasibility of the intended system.
In this article, the throughput of reconfigurable intelligent surfaces (RIS) is improved using adaptive modulation and coding (AMC). The best modulation and coding scheme (MCS) is selected at the transmitter using the...
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In this article, the throughput of reconfigurable intelligent surfaces (RIS) is improved using adaptive modulation and coding (AMC). The best modulation and coding scheme (MCS) is selected at the transmitter using the instantaneous signal to noise ratio (SNR) measured at the receiver and sent back on the feedback channel. RIS is placed between the transmitter and the receiver so that the SNR is maximised at the receiver side as RIS reflections are combined coherently at the receiver and results in significant spatial diversity. All reflections on RIS have a zero phase at the receiver. We show that RIS using AMC offers a larger throughput than conventional RIS with fixed MCS for all SNR range. RIS with AMC offers 48, 42, 36, 30, 24, 18 dB gain for N = 256, 128, 64, 32, 16, 8 reflectors. We obtained 10 dB gain when RIS uses AMC versus 256-QAM. We also improve the throughput of Simultaneously Transmitting And Reflecting RIS (STARRIS) using AMC. We obtained 13 dB gain when STARRIS uses AMC versus 256-QAM.
This paper compares the service quality between 4G and 5G New Radio (NR) among different sub-6 GHz frequency bands in an urban micro-cellular outdoor setting. An updated version of LTE-Sim is considered to obtain the ...
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This paper compares the service quality between 4G and 5G New Radio (NR) among different sub-6 GHz frequency bands in an urban micro-cellular outdoor setting. An updated version of LTE-Sim is considered to obtain the exponential effective signal-to-interference-plus-noise ratio in 4G while determining the modulation and coding scheme. System capacity is obtained by considering a video application at 3.1 Mb/s and the proportional fair (PF) scheduler while comparing 4G and 5G NR through system-level simulations (the 5G-air-simulator is considered for 5G NR). The modified largest weighted delay first (M-LWDF) scheduler is compared with the PF, though only in 4G. Optimal system performance is reached both in 4G and 5G NR for cell radii longer than two times the breakpoint distance (or beyond), which are preferable compared to the shortest values for the cell radius. We have learned that the packet loss ratio (PLR) is higher for the cell radii, R, shorter than breakpoint distance, d(BP)'. For d(BP)' <= R <= 1000 m, the PLR first decreases and then increases. For a target PLR < 2%, in 4G, the highest maximum average goodput is obtained with the M-LWDF scheduler (10-25% increase). This maximum occurs at the 2.6 GHz and 3.5 GHz frequency bands for 300 <= R <= 500 m, while at 5.62 GHz the highest goodput occurs for the longest Rs. With 5G NR and the PF, the maximum average goodput increases, in our simulations, from approximate to 14.1 (in 4G) to 26.1 Mb/s (20 MHz bandwidth).
This paper presents the effect of joint modulation and coding scheme (MCS) selection on a turbo soft interference canceller (SIC) for OFDM-MIMO multiplexing using adaptive modulation and coding (AMC). We use a turbo S...
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ISBN:
(纸本)9781479903085
This paper presents the effect of joint modulation and coding scheme (MCS) selection on a turbo soft interference canceller (SIC) for OFDM-MIMO multiplexing using adaptive modulation and coding (AMC). We use a turbo SIC to detect signals by performing iterative interference cancellation using soft-symbol estimates based on the a posteriori log-likelihood ratio (LLR) at the Max-Log-MAP decoder output and linear minimum mean-square error (LMMSE)-based signal detection. Joint MCS section selects the best MCS combinations of all transmission streams so that the total throughput is maximized considering the residual interference from other streams for the turbo SIC. Computer simulations show that the joint MCS selection mitigates the decrease in throughput due to the large difference in the peak data rate between consecutive MCSs compared to independent MCS selection. Hence, we show that by using joint MCS selection, the total throughput with the number of MCSs of N-MCS = 8 becomes almost identical to that for N-MCS = 12 for 4-by-4 MIMO multiplexing using the turbo SIC.
Outdated channel quality indicator (CQI) feedback causes severe performance degradation of traditional link adaptation (LA) techniques in long term evolution (LTE) and new radio (NR) systems. This paper puts forth a d...
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Outdated channel quality indicator (CQI) feedback causes severe performance degradation of traditional link adaptation (LA) techniques in long term evolution (LTE) and new radio (NR) systems. This paper puts forth a deep reinforcement learning (DRL) based link adaptation (LA) technique, referred to as deep reinforcement learning link adaptation (DRLLA), to select efficient modulation and coding scheme (MCS) in the presence of the outdated CQI feedback. The goal of DRLLA is to maximize the link throughput while achieving a low block error rate (BLER). We first give explicit definitions of state, action, and reward in DRL paradigms, thereby realizing DRLLA. Then, to trade off the throughput against the BLER, we further develop a new experience replay mechanism called classified experience replay (CER) as the underpinning technique in DRLLA. In CER, experiences are separated into two buckets, one for successful experiences and the other for failed experiences, and then a fixed proportion from each is sampled to replay. The essence of CER is to obtain different trade-offs via adjusting the proportion among different training experiences. Furthermore, to reduce the signaling overhead and the system reconfiguration cost caused by frequent MCS switching, we propose a new action selection strategy termed as switching controlled e-greedy (SC -e-greedy) for DRLLA. Simulation results demonstrate that compared with the state-of-the-art OLLA, LTSLA, and DRLLA with other experience replay mechanisms, DRLLA with CER can achieve higher throughput and lower BLER in various time-varying scenarios, and be more robust to different CQI feedback delays and CQI reporting periods. Furthermore, with the SC -e-greedy policy, DRLLA can capture better trade-offs between the link transmission quality and the MCS switching overhead compared with other baselines.
In this letter, we propose a deep Q-network (DQN)-based joint adaptive scheduling algorithm of modulation and coding scheme (MCS) and space division multiplexing (SDM) in 5G massive MIMO-OFDM, that enables the next-ge...
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In this letter, we propose a deep Q-network (DQN)-based joint adaptive scheduling algorithm of modulation and coding scheme (MCS) and space division multiplexing (SDM) in 5G massive MIMO-OFDM, that enables the next-generation NodeB (gNB) to choose optimal MCS and SDM for downlink scheduling that maximizes the spectral efficiency (SE) and throughput while in a low block error rate (BLER). The simulation results show that in the typical high-speed mobile and uplink interference scenarios, the proposed DQN-based algorithm has a 10% to 40% improvement in SE and a 10% to 20% improvement in throughput compared to representative algorithms, and can effectively compensate for the channel state information (CSI) feedback delay.
5G cellular systems provide a new service called Ultra-Reliable Low-Latency Communications (URLLC). In many URLLC scenarios (e.g., intelligent transport systems), users move at high speed and transmit data in the upli...
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5G cellular systems provide a new service called Ultra-Reliable Low-Latency Communications (URLLC). In many URLLC scenarios (e.g., intelligent transport systems), users move at high speed and transmit data in the uplink. The base station shall assign transmission parameters that satisfy the strict quality of service requirements of URLLC applications and consume the least amount of channel resources. At high speed, users often change the serving base station. In this case, the task of selecting transmission parameters is complicated by the fact that the base station does not have channel quality measurements for the new user. This paper proposes various methods for selecting the initial transmission parameters when user connects to the base station. Using simulations, the paper compares various methods for different user speeds. Recommendations are given on the selection of initial parameters that provide a low amount of consumed channel resources.
Ultra-dense low earth orbit (LEO) satellite terrestrial networks (ULSNs) are considered as a crucial component of future six generation (6G) networks, offering ubiquitous and massive services for various applications....
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ISBN:
(纸本)9798350387414
Ultra-dense low earth orbit (LEO) satellite terrestrial networks (ULSNs) are considered as a crucial component of future six generation (6G) networks, offering ubiquitous and massive services for various applications. However, for the development of advanced physical layer technologies for ULSNs, a comprehensive link-level simulation tool that integrates up-to-date satellite communication protocols becomes paramount and is urgently needed. In this paper, we develop a versatile simulator for the link-level performance analysis of ULSNs under the prevalent digital video broadcasting (DVB) standards. We first establish a complete satellite-terrestrial microwave channel model, taking practical factors such as rain attenuation, cloud attenuation, and Doppler frequency shift into consideration. Subsequently, the whole physical layer modules tailored for satellite-terrestrial microwave communication are implemented, including diverse physical layer modulation and coding schemes (MCSs). Furthermore, we realize adaptive coding and modulation (ACM) for adaptive channel performance simulation. Finally, comparative performance analysis using the established channel model is conducted to demonstrate the effectiveness of different MCSs of DVB standards. The complete link-level performance analysis based on our self-developed simulator can advance the field of satellite-terrestrial microwave communication and provide valuable insights for further exploration of ULSNs.
Low-earth-orbit (LEO) satellite-terrestrial network (LSTN) is expected to play a significant role in the next-generation wireless networks (6G), providing global coverage and facilitating various 6G applications. Howe...
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ISBN:
(纸本)9798350378412
Low-earth-orbit (LEO) satellite-terrestrial network (LSTN) is expected to play a significant role in the next-generation wireless networks (6G), providing global coverage and facilitating various 6G applications. However, the high dynamics of channel state information (CSI) in LSTN have posed challenges to modulation and coding schemes (MCS), which adversely affects the correctness of data transmission and the quality of service (QoS) expected by users. To enhance the communication reliability of LSTN, in this paper, we investigate the adaptive coding and modulation (ACM) method under the digital video broadcasting (DVB) standards. We first establish a channel model and then introduce an ACM method involving channel state estimation, channel state prediction, and MCS switching. Subsequently, the least squares (LS) algorithm is leveraged for channel estimation and we propose an ARIMA-Bidirectional Long Short-Term Memory (AB-LSTM) algorithm specifically for forecasting time-series signal-to-noise ratio (SNR) values for precise channel prediction. Then MCS switching is conducted based on the predicted SNR and switching threshold based on DVB standards. We conduct extensive simulations to show that our proposed algorithms can achieve higher estimation and prediction accuracy, and the introduced ACM method can effectively optimize the usage of channel capacity.
To enhance the coverage and transmission reliability, repetitions adopted by Narrowband Internet of Things (NB-IoT) allow repeating transmissions several times. However, this results in a waste of radio resources when...
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To enhance the coverage and transmission reliability, repetitions adopted by Narrowband Internet of Things (NB-IoT) allow repeating transmissions several times. However, this results in a waste of radio resources when the signal strength is high. In addition, in low signal quality, the selection of a higher modulation and coding scheme (MCS) level leads to a huge packet loss in the network. Moreover, the number of physical resource blocks (PRBs) per-user needs to be chosen dynamically, such that the utilization of radio resources can be improved on per-user basis. Therefore, in NB-IoT systems, dynamic adaptation of repetitions, MCS, and radio resources, known as auto link-configuration, is crucial. Accordingly, in this paper, we propose SmartCon which is a Generative Adversarial Network (GAN)-based deep learning approach for auto link-configuration during uplink or downlink scheduling, such that the packet loss rate is significantly reduced in NB-IoT networks. For the training purpose of the GAN, we use a Multi-Armed Bandit (MAB)-based reinforcement learning mechanism that intelligently tunes its output depending on the present network condition. The performance of SmartCon is thoroughly evaluated through simulations where it is shown to significantly improve the performance of NB-IoT systems compared to baseline schemes.
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