Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy...Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy efficiency.Based on the analysis of the 6G MTC key performance indicators(KPIs)and scenario characteristics,this paper summarizes its requirements for radio access networks.Following this,the existing multiple access models are analyzed under these standards to determine UMA's advantages for 6G MTC according to its design characteristics.The critical technology of UMA is the design of its multiple-access coding scheme.Therefore,the existing UMA coding schemes from different coding paradigms are further summarized and compared.In particular,this paper comprehensively considers the energy efficiency and computational complexity of these schemes,studies the changes of the above two indexes with the increase of access scale,and considers the trade-off between the two.It is revealed by the above analysis that some guiding rules of UMA coding design.Finally,the open problems and potentials in this field are given for future research.展开更多
Massive machine type communications(mMTC)have been regarded as promising applications in the future.One main feature of mMTC is short packet communication.Different from traditional long packet communication,short pac...Massive machine type communications(mMTC)have been regarded as promising applications in the future.One main feature of mMTC is short packet communication.Different from traditional long packet communication,short packet communication suffers from transmission rate degradation and a significant error rate is introduced.In this case,traditional resource allocation scheme for mMTC is no longer applicable.In this paper,we explore resource allocation for cellular-based mMTC in the finite blocklength regime.First,to mitigate the load of the base station(BS),we establish a framework for cellularbased mMTC,where MTCGs reuse the resources of cellular users(CUs),aggregate the packets generated by MTCDs,and forward them to the BS.Next,we adopt short packet theory to obtain the minimum required blocklength of a packet that transmits a certain amount of information.Then,by modeling the process of MTCGs-assisted communication as a queuing process,we derive the closed-form expression of the average delay of all MTCDs.Guided by this,we propose a joint power allocation and spectrum sharing scheme to minimize the average delay.Finally,the simulation results verify the correctness of the theoretical results and show that the proposed scheme can reduce the average delay efficiently.展开更多
针对海量机器类通信(Massive Machine Type Communications,mMTC)场景下传统随机接入存在大量前导碰撞问题,提出了一种对终端侧和基站侧的接入改进算法,利用前导标记序列和固定位置随机接入终端的定时提前(Timing Advance,TA)信息,使得...针对海量机器类通信(Massive Machine Type Communications,mMTC)场景下传统随机接入存在大量前导碰撞问题,提出了一种对终端侧和基站侧的接入改进算法,利用前导标记序列和固定位置随机接入终端的定时提前(Timing Advance,TA)信息,使得基站能合理地确定应该向哪些终端回复随机接入响应消息,避免碰撞终端占用资源发送消息3(Message 3,Msg3),实现前导高效利用。仿真表明,该算法在均匀分布和Beta分布接入模型下均能有效降低前导碰撞概率,提高终端的接入成功率,并且拥有合理的平均接入时延。展开更多
A fundamental requirement for any cellular system is the possibility for the device to request a connection setup, commonly referred to as random access procedure. In LTE （long term evolution） networks, the distribu...A fundamental requirement for any cellular system is the possibility for the device to request a connection setup, commonly referred to as random access procedure. In LTE （long term evolution） networks, the distribution of a limited number of radio resources among H2H （Human-to-Human） users and increasing number of MTC （Machine-Type-Communication） devices in M2M （Machine-to-Machine） communications is one of the main problems. An analytical model is conducted to compute the throughput for message 1 and message 2. This is done using a Markov chain model for the four messages signaling flow with buffering for message 4. This model is used in LTE 3GPP （Third-Generation Partnership Project） random access. The network performance will be enhanced by determining a dedicated arrival rate corresponding to maximum throughput of message 2 that will assist the network planner to optimize the network performance. In this paper, a deduced arrival rate less than 3.333 requests/ms will maximize network throughput.展开更多
Non-orthogonal multiple access(NOMA)has emerged as one important enabling technology for future wireless communications and services,including machine type communication(MTC).Unfortunately,supporting diverse MTC servi...Non-orthogonal multiple access(NOMA)has emerged as one important enabling technology for future wireless communications and services,including machine type communication(MTC).Unfortunately,supporting diverse MTC services and massive connectivity is still challenging due to the very different service requirements,scarce radio resources,limited battery capacity of MTC devices,as well as rapidly changing network conditions.In this paper,a hybrid-multipleaccess(HMA)scheme for service-oriented resource allocation scheme is proposed in supporting diverse MTC services for resource constrained devices and networks.In the proposed scheme,HMA allows MTC devices to choose a suitable type of multiple access technique according to their channel conditions,power constraints,and quality of service(QoS)requirements.To support service-oriented resource allocation,the physical network is firstly sliced into several virtualized networks based on QoS requirements and hardware conditions of MTC devices.A novel utility function integrating network performance and the power consumption in MTC devices is proposed.Furthermore,the resource allocation problem is formulated as an optimization problem to maximize the different utility functions under constraints of user QoS requirements and maximum transmitted power.To improve computational capacity as well as reduce the operational latency,a cloud-edge collaborative scheme is further designed to share the computation loads between the cloud and edge.Simulation results demonstrate the proposed service-oriented resource allocation scheme is effective and illustrate that the proposed hybrid multiple access method provides better performance than NOMA in terms of effective energy efficiency.展开更多
机器类型通信(Machine Type Communication,MTC)在5G场景中的应用比例大幅增长。这一类型通信的主要目的是在尽可能减少人工干预的情况下,实现机器类型设备(Machine Type Device,MTD)之间的自主通信。在大规模机器类型通信(massive Mach...机器类型通信(Machine Type Communication,MTC)在5G场景中的应用比例大幅增长。这一类型通信的主要目的是在尽可能减少人工干预的情况下,实现机器类型设备(Machine Type Device,MTD)之间的自主通信。在大规模机器类型通信(massive Machine Type Communication,m MTC)场景中,随机接入(Random Access,RA)冲突是导致网络性能较差的关键因素。为了减轻RA阶段的MTD冲突,提出一种基于双队列分析模型的分布式接入控制方法。相较于中心式控制方法,分布式方法可以明显降低信令开销。此外,仿真表明,提出的方法在系统中设备数量较为稳定时具有更高的吞吐量。展开更多
基金supported by National Natural Science Foundation of China under Grant 61971062,Grant 92067202,Grant 62071058,Grant 62001049Beijing Natural Science Foundation under Grant 4222012Beijing University of Posts and Telecommunications China Mobile Research Institute Joint Innovation Center。
文摘Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy efficiency.Based on the analysis of the 6G MTC key performance indicators(KPIs)and scenario characteristics,this paper summarizes its requirements for radio access networks.Following this,the existing multiple access models are analyzed under these standards to determine UMA's advantages for 6G MTC according to its design characteristics.The critical technology of UMA is the design of its multiple-access coding scheme.Therefore,the existing UMA coding schemes from different coding paradigms are further summarized and compared.In particular,this paper comprehensively considers the energy efficiency and computational complexity of these schemes,studies the changes of the above two indexes with the increase of access scale,and considers the trade-off between the two.It is revealed by the above analysis that some guiding rules of UMA coding design.Finally,the open problems and potentials in this field are given for future research.
基金supported by the Jiangsu Provincial Natural Science Fund for Outstanding Young Scholars(No.BK20180028)the Natural Science Foundations of China(No.61671474,No.61771487)the Jiangsu Provincial Natural Science Fund for Excellent Young Scholars(No.BK20170089).
文摘Massive machine type communications(mMTC)have been regarded as promising applications in the future.One main feature of mMTC is short packet communication.Different from traditional long packet communication,short packet communication suffers from transmission rate degradation and a significant error rate is introduced.In this case,traditional resource allocation scheme for mMTC is no longer applicable.In this paper,we explore resource allocation for cellular-based mMTC in the finite blocklength regime.First,to mitigate the load of the base station(BS),we establish a framework for cellularbased mMTC,where MTCGs reuse the resources of cellular users(CUs),aggregate the packets generated by MTCDs,and forward them to the BS.Next,we adopt short packet theory to obtain the minimum required blocklength of a packet that transmits a certain amount of information.Then,by modeling the process of MTCGs-assisted communication as a queuing process,we derive the closed-form expression of the average delay of all MTCDs.Guided by this,we propose a joint power allocation and spectrum sharing scheme to minimize the average delay.Finally,the simulation results verify the correctness of the theoretical results and show that the proposed scheme can reduce the average delay efficiently.
文摘A fundamental requirement for any cellular system is the possibility for the device to request a connection setup, commonly referred to as random access procedure. In LTE （long term evolution） networks, the distribution of a limited number of radio resources among H2H （Human-to-Human） users and increasing number of MTC （Machine-Type-Communication） devices in M2M （Machine-to-Machine） communications is one of the main problems. An analytical model is conducted to compute the throughput for message 1 and message 2. This is done using a Markov chain model for the four messages signaling flow with buffering for message 4. This model is used in LTE 3GPP （Third-Generation Partnership Project） random access. The network performance will be enhanced by determining a dedicated arrival rate corresponding to maximum throughput of message 2 that will assist the network planner to optimize the network performance. In this paper, a deduced arrival rate less than 3.333 requests/ms will maximize network throughput.
文摘Non-orthogonal multiple access(NOMA)has emerged as one important enabling technology for future wireless communications and services,including machine type communication(MTC).Unfortunately,supporting diverse MTC services and massive connectivity is still challenging due to the very different service requirements,scarce radio resources,limited battery capacity of MTC devices,as well as rapidly changing network conditions.In this paper,a hybrid-multipleaccess(HMA)scheme for service-oriented resource allocation scheme is proposed in supporting diverse MTC services for resource constrained devices and networks.In the proposed scheme,HMA allows MTC devices to choose a suitable type of multiple access technique according to their channel conditions,power constraints,and quality of service(QoS)requirements.To support service-oriented resource allocation,the physical network is firstly sliced into several virtualized networks based on QoS requirements and hardware conditions of MTC devices.A novel utility function integrating network performance and the power consumption in MTC devices is proposed.Furthermore,the resource allocation problem is formulated as an optimization problem to maximize the different utility functions under constraints of user QoS requirements and maximum transmitted power.To improve computational capacity as well as reduce the operational latency,a cloud-edge collaborative scheme is further designed to share the computation loads between the cloud and edge.Simulation results demonstrate the proposed service-oriented resource allocation scheme is effective and illustrate that the proposed hybrid multiple access method provides better performance than NOMA in terms of effective energy efficiency.
文摘机器类型通信(Machine Type Communication,MTC)在5G场景中的应用比例大幅增长。这一类型通信的主要目的是在尽可能减少人工干预的情况下,实现机器类型设备(Machine Type Device,MTD)之间的自主通信。在大规模机器类型通信(massive Machine Type Communication,m MTC)场景中,随机接入(Random Access,RA)冲突是导致网络性能较差的关键因素。为了减轻RA阶段的MTD冲突,提出一种基于双队列分析模型的分布式接入控制方法。相较于中心式控制方法,分布式方法可以明显降低信令开销。此外,仿真表明,提出的方法在系统中设备数量较为稳定时具有更高的吞吐量。
