Abstract
Efficient and Reliable Protocols Design
for Cooperative Radio Networks
Minhwan Choi
Dept. of Electronics and Communication Engineering
The Graduate School
Hanyang University
The main concern of the existing mobile communication technology was the
increase of ...
Abstract
Efficient and Reliable Protocols Design
for Cooperative Radio Networks
Minhwan Choi
Dept. of Electronics and Communication Engineering
The Graduate School
Hanyang University
The main concern of the existing mobile communication technology was the
increase of the transmission rate. Future-oriented communication services,
however, are not only achieving high data rates but also ensuring high reliability
and reducing latency. Since real-time control and processing services are required
in many industries such as self-driving cars, formation flight control of UAVs,
remote surgery & operation, and factory automation based on the cyber-physical
system (CPS). In order to provide ultra-reliable low-latency communication
(URLLC) service, there are many methods such as reducing the size of the header
of packets or adaptive packet redesign, changing the scheduling techniques, and so
on. But the best way of cutting down the total delay time is to minimize the
number of possible re-transmissions by transmitting and receiving highly reliable
signals. In addition, there will be a growing demand for converged networks such
as smart factories, cloud computing, -Health and smart grid in the near future.
Therefore, it is essential to develop a network configuration technology that
enables multiple devices to share URLLC-based information beyond one-to-one
communication.
Assuming that time and frequency resources are limited, the maximum ratio
combining (MRC) is a representative technique for improving the reliability by
using multiple antennas in transmitter and receiver. MRC can obtain the maximum
spatial diversity gain by using the channel state information (CSI) between the
transmitting and receiving antennas known from the training sequence or the pilot
signals. However, since the transmitter cannot estimate the CSI information, it
must satisfy the closed loop condition that feeds back the CSI from the receiver.
Only then you can use the maximum ratio transmission (MRT) operated by
appropriately allocating power. But, the feedback signal has the disadvantage that
it must use some frequency or time resources.
In order to solve the above problem, a space-time block code (STBC) was
proposed, which can achieve maximum diversity gain without CSI feedback. STBC
is a technique for acquiring maximum diversity gain by assigning orthogonality
between channels to a received signal. STBC with two antennas can establish
perfect orthogonality in the complex plane. Since perfect orthogonality cannot be
established in the presence of three or more inputs, quasi-orthogonal STBC of
extended form was proposed.
Next, the cooperative communication technique for delivering a reliable signal
over relays to relatively remote devices is introduced. In general, there is an
amplify-and-forward (AF) scheme for simply amplifying and retransmitting a
signal received from a transmitter at relays. Otherwise, the decode-and-forward
(DF) the scheme can restore the received signal in the relay, and then relay
retransmits the symbol of undergoing improvements. In this paper, the optimal
relay selection technique and an asymptotic analysis model that communicate with
the relay with the largest amplitude value of the CSI coefficient among AF based
relays are proposed. Besides, various cooperative communication systems using
distributed STBC and multi-hop relaying are represented, and the performance
improvement of the proposed methods can be confirmed, through the simulation
and analysis model.
Finally, there is a growing demand for communication technologies that require
information to be shared among all devices, not just the most distant devices. In
other words, it is necessary to research and develop the ad-hoc network that the
device itself constitutes the communication network beyond the central control. In
this paper, I propose a scheme to share information among multiple nodes in full
duplex that can acquire frequency resources more than twice. It can be evaluated
that the performance of the proposed method is superior to that of the
conventional half-duplex method by using the interference cancellation, the signal
combining, and the adaptive switching method.
The performances of various aspects such as the statistical throughput, the
information outage probability (IOP), and a bit error rate (BER) versus the
average signal to noise ratio (SNR) for each proposed technique are compared
with simulation and analytical equations to evaluate the improved performance.
Abstract
Efficient and Reliable Protocols Design
for Cooperative Radio Networks
Minhwan Choi
Dept. of Electronics and Communication Engineering
The Graduate School
Hanyang University
The main concern of the existing mobile communication technology was the
increase of the transmission rate. Future-oriented communication services,
however, are not only achieving high data rates but also ensuring high reliability
and reducing latency. Since real-time control and processing services are required
in many industries such as self-driving cars, formation flight control of UAVs,
remote surgery & operation, and factory automation based on the cyber-physical
system (CPS). In order to provide ultra-reliable low-latency communication
(URLLC) service, there are many methods such as reducing the size of the header
of packets or adaptive packet redesign, changing the scheduling techniques, and so
on. But the best way of cutting down the total delay time is to minimize the
number of possible re-transmissions by transmitting and receiving highly reliable
signals. In addition, there will be a growing demand for converged networks such
as smart factories, cloud computing, -Health and smart grid in the near future.
Therefore, it is essential to develop a network configuration technology that
enables multiple devices to share URLLC-based information beyond one-to-one
communication.
Assuming that time and frequency resources are limited, the maximum ratio
combining (MRC) is a representative technique for improving the reliability by
using multiple antennas in transmitter and receiver. MRC can obtain the maximum
spatial diversity gain by using the channel state information (CSI) between the
transmitting and receiving antennas known from the training sequence or the pilot
signals. However, since the transmitter cannot estimate the CSI information, it
must satisfy the closed loop condition that feeds back the CSI from the receiver.
Only then you can use the maximum ratio transmission (MRT) operated by
appropriately allocating power. But, the feedback signal has the disadvantage that
it must use some frequency or time resources.
In order to solve the above problem, a space-time block code (STBC) was
proposed, which can achieve maximum diversity gain without CSI feedback. STBC
is a technique for acquiring maximum diversity gain by assigning orthogonality
between channels to a received signal. STBC with two antennas can establish
perfect orthogonality in the complex plane. Since perfect orthogonality cannot be
established in the presence of three or more inputs, quasi-orthogonal STBC of
extended form was proposed.
Next, the cooperative communication technique for delivering a reliable signal
over relays to relatively remote devices is introduced. In general, there is an
amplify-and-forward (AF) scheme for simply amplifying and retransmitting a
signal received from a transmitter at relays. Otherwise, the decode-and-forward
(DF) the scheme can restore the received signal in the relay, and then relay
retransmits the symbol of undergoing improvements. In this paper, the optimal
relay selection technique and an asymptotic analysis model that communicate with
the relay with the largest amplitude value of the CSI coefficient among AF based
relays are proposed. Besides, various cooperative communication systems using
distributed STBC and multi-hop relaying are represented, and the performance
improvement of the proposed methods can be confirmed, through the simulation
and analysis model.
Finally, there is a growing demand for communication technologies that require
information to be shared among all devices, not just the most distant devices. In
other words, it is necessary to research and develop the ad-hoc network that the
device itself constitutes the communication network beyond the central control. In
this paper, I propose a scheme to share information among multiple nodes in full
duplex that can acquire frequency resources more than twice. It can be evaluated
that the performance of the proposed method is superior to that of the
conventional half-duplex method by using the interference cancellation, the signal
combining, and the adaptive switching method.
The performances of various aspects such as the statistical throughput, the
information outage probability (IOP), and a bit error rate (BER) versus the
average signal to noise ratio (SNR) for each proposed technique are compared
with simulation and analytical equations to evaluate the improved performance.
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