In this paper a new method to improve performance of cooperative underwater acoustic (UWA) sensor networks will be introduced. The method is based on controlling and optimizing carrier frequencies which are used in da...In this paper a new method to improve performance of cooperative underwater acoustic (UWA) sensor networks will be introduced. The method is based on controlling and optimizing carrier frequencies which are used in data links between network nods. In UWA channels Pathloss and noise power spectrum density (psd) are related to carrier frequency. Therefore, unlike radio communications, in UWA Communications signal to noise ratio (SNR) is related to frequency besides propagation link length. In such channels an optimum frequency in whole frequency band and link lengths cannot be found. In Cooperative transmission, transmitter sends one copy of transmitted data packets to relay node. Then relay depending on cooperation scheme, amplifies or decodes each data packet and retransmit it to destination. Receiver uses and combines both received signals to estimate transmitted data. This paper wants to propose a new method to decrease network power consumptions by controlling and sub-optimizing transmission frequency based on link length. For this purpose, underwater channel parameters is simulated and analyzed in 1km to 10km lengths (midrange channel). Then link lengths sub categorized and in each category, optimum frequency is computed. With these sub optimum frequencies, sensors and base station can adaptively control their carrier frequencies based on link length and decrease network’s power consumptions. Finally Different Cooperative transmission schemes “Decode and Forward (DF)” and “Amplify and Forward (AF)”, are simulated in UWA wireless Sensor network with and without the new method. In receiver maximum ratio combiner (MRC) is used to combining received signals and making data estimations. Simulations show that the new method, called AFC cooperative UWA communication, can improve performance of underwater acoustic wireless sensor networks up to 40.14%.展开更多
With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media a...With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media access control (MAC) protocols, which allow multiple users to share the common medium fairly and efficiently, are essential for the performance of UASNs. However, the design of MAC protocols is confronted with the challenges of spatial unfairness, data eruption, and low energy efficiency. In this paper, we propose a novel data concurrent transmission (DCT) MAC protocol, which is able to exploit long propagation delay and conduct concurrent transmission. Specifically, we present the theoretical performance analysis of the proposed MAC protocol in detail and give an analytical solution of the success concurrent transmission probability between nodes. In addition, simulation results are provided to demonstrate that our proposed protocol is appropriate for UASNs and can significantly improve the performance in terms of network throughput and energy consumption. Finally, we give some typical future applications of UASNs and discuss the demands on MAC protocol design.展开更多
The simulation of underwater acoustic information flow is an important way to research sonar performance and its engagement effectiveness in the ocean environment.This paper analyzes the significance of modeling an op...The simulation of underwater acoustic information flow is an important way to research sonar performance and its engagement effectiveness in the ocean environment.This paper analyzes the significance of modeling an open and sophisticated simulation software architecture by object-oriented method,and introduces the modeling processes and expression method of simulation architecture.According to the requirements of simulation system and the underwater acoustic information flow,the logical architecture of simulation software system is modeled by the object-oriented method.A use-case view captured the system requirements.The logical view shows the logical architecture of software system.The simulation software is decomposed into the loose coupling constituent parts by layering and partitioning the packages for maintainability.The design patterns enabled the simulation software to have good expansibility and reusability.The simulation system involving multi-targets and multi-sonar is developed based on the architecture model.Practices show that the model meets the needs for simulating an open and sophisticated system.展开更多
针对现有密钥分发协议在水声信道环境下的信息泄露问题,提出了一种基于细粒度极化的隐蔽密钥分发(Covert Secret-key distribution based on Fine-grained Polarization,CSFP)方案.首先,采用一致最大功效检验方法建立敌手模型,并给出隐...针对现有密钥分发协议在水声信道环境下的信息泄露问题,提出了一种基于细粒度极化的隐蔽密钥分发(Covert Secret-key distribution based on Fine-grained Polarization,CSFP)方案.首先,采用一致最大功效检验方法建立敌手模型,并给出隐蔽密钥分发方案的形式化定义.考虑到水声信道的非对称性和衰落效应,根据注水原理推导出信息传输速率达到香农极限时最优码字符号分布对应的带宽以及信道容量,并利用莱布尼兹积分法则和黎曼积分的保号性推导出信道容量与信道增益的函数关系,通过计算水声信道增益对极化子信道的容量进行排序实现极化码的码字构造,确保信息传输速率达到香农极限.其次,对信息比特索引集合进行细粒度极化,采用链式结构将多个消息块依次链接实现信息比特索引序列的对齐,设计出多轮通信下隐蔽密钥分发的编码和解码算法,利用合法发送方和接收方共享的随机种子对首轮传输的消息块进行初始化,并从当前生成的密钥中提取出随机种子对后续消息块进行随机化,确保密钥分发过程的隐蔽性.最后,通过信息理论证明了CSFP方案的可靠性、随机性、保密性和隐蔽性,利用最大熵原理推导出水声信道环境下隐蔽性约束的可达性条件和隐蔽密钥生成速率.仿真结果表明,与现有方案相比,CSFP方案的隐蔽密钥生成速率平均提高了18.78%,隐蔽概率平均提高了38.29%.此外,CSFP方案生成的密钥成功通过了SP 800-22测试平台的随机性检测.展开更多
水声信道面临带宽资源有限、环境复杂的问题,为提高水下通信速率,基于水声传感器网络的海洋应用提出自适应通信的需求。传统基于简单信噪比指标的自适应资源分配算法无法准确表述衰落信道的统计特征,利用强化学习和卷积神经网络预测信...水声信道面临带宽资源有限、环境复杂的问题,为提高水下通信速率,基于水声传感器网络的海洋应用提出自适应通信的需求。传统基于简单信噪比指标的自适应资源分配算法无法准确表述衰落信道的统计特征,利用强化学习和卷积神经网络预测信道的方法虽然可以提高一定信道状态信息(channel state information,CSI)的准确性,但这种方法需要长期的观测和大量的训练样本,不符合水声环境的实际情况。对比,构建了一种中继放大转发协作正交频分复用(orthogonal frequency division multiplexing,OFDM)通信的模型,解决了由于节点漂浮导致直接通信传输效率变低的问题,并提出一种在时延反馈CSI中基于OFDM的自适应功率比特分配算法,利用条件概率表征不完美的CSI,调整自适应通信参数,进行遍历容量最大化建模。仿真结果表明,该算法实现功率和比特的联合自适应分配,平均传输速率指标优于直接反馈CSI的功率分配算法,虽然略低于采用马尔可夫链预测信道的方法,但结合算法复杂度来看,所提算法更简单,更适合能量有限的水声传感器网络。展开更多
文摘In this paper a new method to improve performance of cooperative underwater acoustic (UWA) sensor networks will be introduced. The method is based on controlling and optimizing carrier frequencies which are used in data links between network nods. In UWA channels Pathloss and noise power spectrum density (psd) are related to carrier frequency. Therefore, unlike radio communications, in UWA Communications signal to noise ratio (SNR) is related to frequency besides propagation link length. In such channels an optimum frequency in whole frequency band and link lengths cannot be found. In Cooperative transmission, transmitter sends one copy of transmitted data packets to relay node. Then relay depending on cooperation scheme, amplifies or decodes each data packet and retransmit it to destination. Receiver uses and combines both received signals to estimate transmitted data. This paper wants to propose a new method to decrease network power consumptions by controlling and sub-optimizing transmission frequency based on link length. For this purpose, underwater channel parameters is simulated and analyzed in 1km to 10km lengths (midrange channel). Then link lengths sub categorized and in each category, optimum frequency is computed. With these sub optimum frequencies, sensors and base station can adaptively control their carrier frequencies based on link length and decrease network’s power consumptions. Finally Different Cooperative transmission schemes “Decode and Forward (DF)” and “Amplify and Forward (AF)”, are simulated in UWA wireless Sensor network with and without the new method. In receiver maximum ratio combiner (MRC) is used to combining received signals and making data estimations. Simulations show that the new method, called AFC cooperative UWA communication, can improve performance of underwater acoustic wireless sensor networks up to 40.14%.
基金supported in part by the National Natural Science Foundation of China under Grant 62171405in part by the National Science Fund for Distinguished Young Scholars under Grant 62225114
文摘With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media access control (MAC) protocols, which allow multiple users to share the common medium fairly and efficiently, are essential for the performance of UASNs. However, the design of MAC protocols is confronted with the challenges of spatial unfairness, data eruption, and low energy efficiency. In this paper, we propose a novel data concurrent transmission (DCT) MAC protocol, which is able to exploit long propagation delay and conduct concurrent transmission. Specifically, we present the theoretical performance analysis of the proposed MAC protocol in detail and give an analytical solution of the success concurrent transmission probability between nodes. In addition, simulation results are provided to demonstrate that our proposed protocol is appropriate for UASNs and can significantly improve the performance in terms of network throughput and energy consumption. Finally, we give some typical future applications of UASNs and discuss the demands on MAC protocol design.
文摘The simulation of underwater acoustic information flow is an important way to research sonar performance and its engagement effectiveness in the ocean environment.This paper analyzes the significance of modeling an open and sophisticated simulation software architecture by object-oriented method,and introduces the modeling processes and expression method of simulation architecture.According to the requirements of simulation system and the underwater acoustic information flow,the logical architecture of simulation software system is modeled by the object-oriented method.A use-case view captured the system requirements.The logical view shows the logical architecture of software system.The simulation software is decomposed into the loose coupling constituent parts by layering and partitioning the packages for maintainability.The design patterns enabled the simulation software to have good expansibility and reusability.The simulation system involving multi-targets and multi-sonar is developed based on the architecture model.Practices show that the model meets the needs for simulating an open and sophisticated system.
文摘针对现有密钥分发协议在水声信道环境下的信息泄露问题,提出了一种基于细粒度极化的隐蔽密钥分发(Covert Secret-key distribution based on Fine-grained Polarization,CSFP)方案.首先,采用一致最大功效检验方法建立敌手模型,并给出隐蔽密钥分发方案的形式化定义.考虑到水声信道的非对称性和衰落效应,根据注水原理推导出信息传输速率达到香农极限时最优码字符号分布对应的带宽以及信道容量,并利用莱布尼兹积分法则和黎曼积分的保号性推导出信道容量与信道增益的函数关系,通过计算水声信道增益对极化子信道的容量进行排序实现极化码的码字构造,确保信息传输速率达到香农极限.其次,对信息比特索引集合进行细粒度极化,采用链式结构将多个消息块依次链接实现信息比特索引序列的对齐,设计出多轮通信下隐蔽密钥分发的编码和解码算法,利用合法发送方和接收方共享的随机种子对首轮传输的消息块进行初始化,并从当前生成的密钥中提取出随机种子对后续消息块进行随机化,确保密钥分发过程的隐蔽性.最后,通过信息理论证明了CSFP方案的可靠性、随机性、保密性和隐蔽性,利用最大熵原理推导出水声信道环境下隐蔽性约束的可达性条件和隐蔽密钥生成速率.仿真结果表明,与现有方案相比,CSFP方案的隐蔽密钥生成速率平均提高了18.78%,隐蔽概率平均提高了38.29%.此外,CSFP方案生成的密钥成功通过了SP 800-22测试平台的随机性检测.
文摘水声信道面临带宽资源有限、环境复杂的问题,为提高水下通信速率,基于水声传感器网络的海洋应用提出自适应通信的需求。传统基于简单信噪比指标的自适应资源分配算法无法准确表述衰落信道的统计特征,利用强化学习和卷积神经网络预测信道的方法虽然可以提高一定信道状态信息(channel state information,CSI)的准确性,但这种方法需要长期的观测和大量的训练样本,不符合水声环境的实际情况。对比,构建了一种中继放大转发协作正交频分复用(orthogonal frequency division multiplexing,OFDM)通信的模型,解决了由于节点漂浮导致直接通信传输效率变低的问题,并提出一种在时延反馈CSI中基于OFDM的自适应功率比特分配算法,利用条件概率表征不完美的CSI,调整自适应通信参数,进行遍历容量最大化建模。仿真结果表明,该算法实现功率和比特的联合自适应分配,平均传输速率指标优于直接反馈CSI的功率分配算法,虽然略低于采用马尔可夫链预测信道的方法,但结合算法复杂度来看,所提算法更简单,更适合能量有限的水声传感器网络。
