27 research outputs found
Code-Expanded Random Access for Machine-Type Communications
The random access methods used for support of machine-type communications
(MTC) in current cellular standards are derivatives of traditional framed
slotted ALOHA and therefore do not support high user loads efficiently.
Motivated by the random access method employed in LTE, we propose a novel
approach that is able to sustain a wide random access load range, while
preserving the physical layer unchanged and incurring minor changes in the
medium access control layer. The proposed scheme increases the amount of
available contention resources, without resorting to the increase of system
resources, such as contention sub-frames and preambles. This increase is
accomplished by expanding the contention space to the code domain, through the
creation of random access codewords. Specifically, in the proposed scheme,
users perform random access by transmitting one or none of the available LTE
orthogonal preambles in multiple random access sub-frames, thus creating access
codewords that are used for contention. In this way, for the same number of
random access sub-frames and orthogonal preambles, the amount of available
contention resources is drastically increased, enabling the support of an
increased number of MTC users. We present the framework and analysis of the
proposed code-expanded random access method and show that our approach supports
load regions that are beyond the reach of current systems.Comment: 6 Pages, 7 figures, This paper has been submitted to GC'12 Workshop:
Second International Workshop on Machine-to-Machine Communications 'Key' to
the Future Internet of Thing
Massive Non-Orthogonal Multiple Access for Cellular IoT: Potentials and Limitations
The Internet of Things (IoT) promises ubiquitous connectivity of everything
everywhere, which represents the biggest technology trend in the years to come.
It is expected that by 2020 over 25 billion devices will be connected to
cellular networks; far beyond the number of devices in current wireless
networks. Machine-to-Machine (M2M) communications aims at providing the
communication infrastructure for enabling IoT by facilitating the billions of
multi-role devices to communicate with each other and with the underlying data
transport infrastructure without, or with little, human intervention. Providing
this infrastructure will require a dramatic shift from the current protocols
mostly designed for human-to-human (H2H) applications. This article reviews
recent 3GPP solutions for enabling massive cellular IoT and investigates the
random access strategies for M2M communications, which shows that cellular
networks must evolve to handle the new ways in which devices will connect and
communicate with the system. A massive non-orthogonal multiple access (NOMA)
technique is then presented as a promising solution to support a massive number
of IoT devices in cellular networks, where we also identify its practical
challenges and future research directions.Comment: To appear in IEEE Communications Magazin
Probabilistic Rateless Multiple Access for Machine-to-Machine Communication
Future machine to machine (M2M) communications need to support a massive
number of devices communicating with each other with little or no human
intervention. Random access techniques were originally proposed to enable M2M
multiple access, but suffer from severe congestion and access delay in an M2M
system with a large number of devices. In this paper, we propose a novel
multiple access scheme for M2M communications based on the capacity-approaching
analog fountain code to efficiently minimize the access delay and satisfy the
delay requirement for each device. This is achieved by allowing M2M devices to
transmit at the same time on the same channel in an optimal probabilistic
manner based on their individual delay requirements. Simulation results show
that the proposed scheme achieves a near optimal rate performance and at the
same time guarantees the delay requirements of the devices. We further propose
a simple random access strategy and characterized the required overhead.
Simulation results show the proposed approach significantly outperforms the
existing random access schemes currently used in long term evolution advanced
(LTE-A) standard in terms of the access delay.Comment: Accepted to Publish in IEEE Transactions on Wireless Communication
Long Term Evolution and its Handover Mechanism
LTE technology wascommercially introduced byTeliaSonera in Norway in December2009. The abbreviation of LTE is Long Term Evolution.It is the third generation partnership project(3GPP).It is also developed widely by international organization.LTE is developed to support both the time division duplex technology(TDD) as well as historical information. The Architecture of high level network technology LTE is obtained from the three main point’s 1.The user Equipment, 2.The Evolved UMTS Terrestrial Radio Access Network(E_UTRAN)and 3rd is the (EPC)Evolved PacketCore.Handover mechanism is published to be used in 3GPP LTE in orderto reduce the complexity of LTE Network architecture.The Standards isdeveloped by3GPP and is specie in its release 8 document series, LTE is the natural upgrade path forbid GSM/UMTS networks and CDMA200 networks.A critical task for operators is to plain LTE network layer independently without losing the cooperation
LSTM-Aided Hybrid Random Access Scheme for 6G Machine Type Communication Networks
In this paper, an LSTM-aided hybrid random access scheme (LSTMH-RA) is
proposed to support diverse quality of service (QoS) requirements in 6G
machine-type communication (MTC) networks, where massive MTC (mMTC) devices and
ultra-reliable low latency communications (URLLC) devices coexist. In the
proposed LSTMH-RA scheme, mMTC devices access the network via a timing advance
(TA)-aided four-step procedure to meet massive access requirement, while the
access procedure of the URLLC devices is completed in two steps coupled with
the mMTC devices' access procedure to reduce latency. Furthermore, we propose
an attention-based LSTM prediction model to predict the number of active URLLC
devices, thereby determining the parameters of the multi-user detection
algorithm to guarantee the latency and reliability access requirements of URLLC
devices.We analyze the successful access probability of the LSTMH-RA scheme.
Numerical results show that, compared with the benchmark schemes, the proposed
LSTMH-RA scheme can significantly improve the successful access probability,
and thus satisfy the diverse QoS requirements of URLLC and mMTC devices
Evolutionary game based access class barring for machine-to-machine communications
Machine-to-machine (M2M) communication faces the most critical challenge that when a massive number of MTC devices perform random access, there will be severe congestions. 3GPP developed a network coordinated random access stabilization scheme known as the access class barring(ACB) to deal with the problem in LTE-Advanced. However, MTC devices in overlapped areas still suffer severe access delays due to the noncooperation and individual setting of ACB factor among BSs. We propose evolutionary game based ACB algorithm to help MTC devices alleviate congestions and thus eliminate substantial defects in the ordinary ACB. Finally, the performance of the evolutionary game based ACB algorithm is analysed, and simulation results show the convergence and effectiveness of the proposed algorithm. ? 2014 Global IT Research Institute (GIRI).EICPCI-S(ISTP)