In this paper, we study the feasibility of a hybrid scheduling approach for broadcast systems in frequency selective fading channels. The hybrid scheduling approach consists of two
components: a first broadcast component and a second unicast component. The unicast component is activated if the mobile fails to correctly decode the packet and thus sends back a
negative acknowledge to the base station. In this paper, we show that there is an optimal modulation and coding schemeto be used for each one of the components presented. The
broadcast optimal modulation and coding scheme depends on the best alignment in fading between different receivers. On the other hand, the unicast optimal modulation and coding
scheme depends on the particular fading profile of each mobile separately.
Improving data transmission in the vanet using multi criteria decision making...ijfcstjournal
In vehicular ad
-
hoc networks the packets are sent using multi
-
hop methods and the receiving limit of a
message is gradually extended, but the exponential increment of the number of nodes re
-
broadcasting a
message results in broadcast storm problem in data
broadcasting in this case. Some characteristics like
high speed of nodes, rapid topological changes and repetitive discontinuities have made it difficult
to
design an efficient broadcasting protocol for these networks.
We have offered a novel fuzzy method
based on multi
-
criteria decision
-
making (MCDM) for prioritizing the
vehicles in selection of the most proper neighbor to broadcast data in this paper. With using this f
uzzy
method, the most proper vehicles participate in data broadcasting. The results of
simulation using NS show
that because of selecting the neighboring vehicles with high priority in data broadcasting, the spee
d of
sending the packs is increased and the network load is considerably decreased. This method also
considerably decreases broadca
sting traffic.
Performance analysis of multilayer multicast MANET CRN based on steiner minim...TELKOMNIKA JOURNAL
In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also, the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (푃퐼) since the primary user’s (PU) traffic load is low when the value of 푃퐼 is high.
Design and Optimal Configuration of Full-Duplex MAC Protocol for Cognitive Ra...Polytechnique Montreal
In this paper, we propose an adaptive medium access control (MAC) protocol for
full-duplex (FD) cognitive radio networks in which FD secondary users (SUs) perform channel contention
followed by concurrent spectrum sensing and transmission, and transmission only with maximum power
in two different stages (called the FD sensing and transmission stages, respectively) in each contention
and access cycle. The proposed FD cognitive MAC (FDC-MAC) protocol does not require synchronization
among SUs, and it efciently utilizes the spectrum and mitigates the self-interference in the FD transceiver.
We develop a mathematical model to analyze the throughput performance of the FDC-MAC protocol, where
both half-duplex (HD) transmission and FD transmission modes are considered in the transmission stage.
Then, we study the FDC-MAC conguration optimization through adaptively controlling the spectrum
sensing duration and transmit power level in the FD sensing stage.We prove that there exists optimal sensing
time and transmit power to achieve the maximum throughput, and we develop an algorithm to congure
the proposed FDC-MAC protocol. Extensive numerical results are presented to illustrate the optimal
FDC-MAC conguration and the impacts of protocol parameters and the self-interference cancellation
quality on the throughput performance. Moreover, we demonstrate the signicant throughput gains of the
FDC-MAC protocol with respect to the existing HD MAC and single-stage FD MAC protocols
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Distributed contention based mac protocol for cognitive radioIffat Anjum
Introduction
System Model
DC-MAC Design
Network Initialization
DC-MAC Working
Data Transfer on Home Channel
Data Transfer on a Foreign Channel
Performance Analysis
Conclusion
References
Improving data transmission in the vanet using multi criteria decision making...ijfcstjournal
In vehicular ad
-
hoc networks the packets are sent using multi
-
hop methods and the receiving limit of a
message is gradually extended, but the exponential increment of the number of nodes re
-
broadcasting a
message results in broadcast storm problem in data
broadcasting in this case. Some characteristics like
high speed of nodes, rapid topological changes and repetitive discontinuities have made it difficult
to
design an efficient broadcasting protocol for these networks.
We have offered a novel fuzzy method
based on multi
-
criteria decision
-
making (MCDM) for prioritizing the
vehicles in selection of the most proper neighbor to broadcast data in this paper. With using this f
uzzy
method, the most proper vehicles participate in data broadcasting. The results of
simulation using NS show
that because of selecting the neighboring vehicles with high priority in data broadcasting, the spee
d of
sending the packs is increased and the network load is considerably decreased. This method also
considerably decreases broadca
sting traffic.
Performance analysis of multilayer multicast MANET CRN based on steiner minim...TELKOMNIKA JOURNAL
In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also, the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (푃퐼) since the primary user’s (PU) traffic load is low when the value of 푃퐼 is high.
Design and Optimal Configuration of Full-Duplex MAC Protocol for Cognitive Ra...Polytechnique Montreal
In this paper, we propose an adaptive medium access control (MAC) protocol for
full-duplex (FD) cognitive radio networks in which FD secondary users (SUs) perform channel contention
followed by concurrent spectrum sensing and transmission, and transmission only with maximum power
in two different stages (called the FD sensing and transmission stages, respectively) in each contention
and access cycle. The proposed FD cognitive MAC (FDC-MAC) protocol does not require synchronization
among SUs, and it efciently utilizes the spectrum and mitigates the self-interference in the FD transceiver.
We develop a mathematical model to analyze the throughput performance of the FDC-MAC protocol, where
both half-duplex (HD) transmission and FD transmission modes are considered in the transmission stage.
Then, we study the FDC-MAC conguration optimization through adaptively controlling the spectrum
sensing duration and transmit power level in the FD sensing stage.We prove that there exists optimal sensing
time and transmit power to achieve the maximum throughput, and we develop an algorithm to congure
the proposed FDC-MAC protocol. Extensive numerical results are presented to illustrate the optimal
FDC-MAC conguration and the impacts of protocol parameters and the self-interference cancellation
quality on the throughput performance. Moreover, we demonstrate the signicant throughput gains of the
FDC-MAC protocol with respect to the existing HD MAC and single-stage FD MAC protocols
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Distributed contention based mac protocol for cognitive radioIffat Anjum
Introduction
System Model
DC-MAC Design
Network Initialization
DC-MAC Working
Data Transfer on Home Channel
Data Transfer on a Foreign Channel
Performance Analysis
Conclusion
References
T HE I MPACT OF TCP C ONGESTION W INDOW S IZE ON THE P ERFORMANCE E VA...ijwmn
A mobile ad hoc network (MANET) is a temporary coll
ection of mobile nodes randomly moved within a
limited terrain area. The nodes are connected to fo
rm a wireless network without use any communication
infrastructure. Because of the limiting resources o
f MANET nodes, multiple hops
scheme is proposed for
data exchange
across the network. Varieties of mobile ad hoc rout
ing protocols have been developed to
support the multi-hop scheme of ad hoc networks. A
popular Transmission Control Protocol (TCP)
provides a reliable connection in a computer networ
k environment; it sets its congestion window size i
n
response to the behavior of the network to achieve
the best performance. This work aims to investigate
and
compare the MANET protocol
performance, such as DSDV, AODV and DSR in terms of
network
throughput, average routing load, the packet delive
ry ratio (PDR), and average end-to-end delay by
varying the maximum congestion window size. Our si
mulation has been implemented using a well-known
NS-2.35 network simulator. The simulated results sh
ow that the demonstrates of the concepts of MANET
routing protocols with respect to TCP congestion wi
ndow size in MANET environment
Hierarchical Genetic Algorithm For Dynamic Channel Units Allocation in TD-CDM...ijwmn
Hierarchical Genetic Algorithms (HGA) as a tool for search and optimizing methodology have now reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU), is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In a cellular network, the call arrival rate, call duration and the communication overhead between the base stations and the control center are vague and uncertain, regardless of whether the criteria of concern are nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network (NN) topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA) in cellular networks. It aims to efficiently satisfy the diverse quality-of-service (QoS) requirements of multimedia traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update overhead, and shorter channel-acquisition delay than previous methods
Multi-Criterion Decision Making and Adaptation for Multi-path Video Streaming...Eswar Publications
It is suggested that multi-path routing is advantageous for applications with high traffic data characteristics, especially in the WSN environment. Sensor networks which transmit video will have to respond to the high data characteristic inherent in video data. Throughput, delay and packet loss are important metrics when considering video traffic. This work measures the performance of four multi-path routing protocols, MAOMDV, AOMDV, AntHocNet and MP-DSR in the WSN environment. It is shown that MAOMDV outperforms the other multi-path routing protocols in terms of the aforementioned metrics.
Long-Term Evolution (LTE), an emerging and promising fourth generation mobile technology, is expected
to offer ubiquitous broadband access to the mobile subscribers. In this paper, the performance of Frame
Level Scheduler (FLS), Exponential (EXP) rule, Logarithmic (LOG) rule and Maximum-Largest Weighted
Delay First (M-LWDF) packet scheduling algorithms has been studied in the downlink 3GPP LTE cellular
network. To this aim, a single cell with interference scenario has been considered. The performance
evaluation is made by varying the number of UEs ranging from 10 to 50 (Case 1) and user speed in the
range of [3, 120] km/h (Case 2). Results show that while the number of UEs and user speed increases, the
performance of the considered scheduling schemes degrades and in both case FLS outperforms other three
schemes in terms of several performance indexes such as average throughput, packet loss ratio (PLR),
packet delay and fairness index.
ACHIEVING ENHANCED THROUGHPUT IN MOBILE ADHOC NETWORK USING COLLISION AWARE M...ijasuc
Since wireless medium is high demand resource the design of an efficient medium access protocol is
important for Mobile Adhoc Networks. As MAC is the base layer in the protocol stack a performance gain
in this layer will have significant improvement in the overall performance of the network. Since the current
IEEE 802.11 MAC standard is not adaptive to the network scenario its performance is poor in terms of
throughput, fairness and delay. Although several alternatives to the existing standard is proposed many of
them are not satisfactorily address the key issues of keeping the simplicity of the protocol and avoiding the
overhead on the nodes on duty in emergency situations where usually adhoc networks are applied. In this
paper we propose an adaptive, collision aware MAC protocol for wireless adhoc networks, termed the
Collision Based Contention (CBC) protocol, in which depends on the current collision level on the shared
medium contending nodes dynamically decides its Backoff value to avoid a blind random waiting before
access to the medium. The CBC scheme outperforms the BEB scheme employed in the IEEE 802.11 MAC
standard and other competing proposals.
What is the purpose of 5G flexible duplexing?
The purpose of 5G flexible duplexing is to allow the most flexible use of an operator's spectrum for time-frequency resources in a single framework. 5G Flexible duplexing should inherently support both paired and unpaired spectrum and be forward compatible with full-duplex 5G.
A DDRESSING T HE M ULTICHANNEL S ELECTION , S CHEDULING A ND C OORDINATION...pijans
We discuss a new multichannel coordination and sche
duling challenge called the Multichannel Scheduling
Cost (MSC). It is caused by the inability of the co
ntrol channel to schedule simultaneous transmission
s
resulting in data channels lying idle and their ban
dwidth underutilized. As a result, wasted bandwidth
increases as the number of data channels increases.
To address this challenge, a cyclic scheduling
Algorithm (CSA) is proposed. It employs one dedicat
ed signaling channel and 4 data channels. It is
premised on a proactive channel reservation scheme
which reduces the idleness of channels. The scheme
ensures that data channels are reserved while they
are still busy. The data channels are reserved whil
e
their remaining transmission duration is equal to t
he virtual carrier sensing duration. This gives the
next
pair sufficient time to reserve the current data ch
annel before it becomes available, limiting the MSC
to the
first cycle. The simulation results show a performa
nce benefit of the CSA scheme in addressing the eff
ects
of the MSC
Quadrant Based DIR in CWin Adaptation Mechanism for Multihop Wireless NetworkIJCI JOURNAL
In Multihop Wireless Networks, traffic forwarding capability of each node varies according to its level of contention. Each node can yield its channel access opportunity to its neighbouring nodes, so that all the nodes can evenly share the channel and have similar forwarding capability. In this manner the wireless channel is utilized effectively, which is achieved using Contention Window Adaptation Mechanism (CWAM). This mechanism achieves a higher end-to-end throughout but consumes the network power to a higher level. So, a newly proposed algorithm Quadrant- Based Directional Routing Protocol (Q-DIR) is implemented as a cross-layer with CWAM, to reduce the total network power consumption through limited flooding and also reduce the routing overheads, which eventually increases overall network throughput. This algorithm limits the broadcast region to a quadrant where the source node and the destination nodes are located. Implementation of the algorithm is done in Linux based NS-2 simulator
QoS -Aware Spectrum Sharing for Multi-Channel Vehicular NetworkIJSRD
We consider QoS -aware band sharing in cognitive wireless networks where secondary users are allowed to access the band owned by a primary network provider. The intrusion from secondary users to primary users is forced to be below the tolerable limit. Also, signal to intrusion plus noise ratio (SINR) of each secondary user is maintained higher than a required level for QoS cover. When network load is high, admission control needs to be performed to satisfy both QoS and intrusion constraint. We propose an admission control algorithm which is performed jointly with power manage such that QoS needs of all admitted secondary users are satisfied while keeping the intrusion to primary users below the passable limit. When all secondary users can be supported at minimum rates, we allow them to increase their spread rates and share the spectrum in a fair manner. We formulate the joint power/rate allocation with max-min equality principle as an optimization problem. We show how to change it into a convex optimization problem so that its globally most favourable solution can be obtained. Numerical grades show that the proposed admission control algorithm achieves performance very close to the optimal solution.
Improved Algorithm for Throughput Maximization in MC-CDMAVLSICS Design
The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .
T HE I MPACT OF TCP C ONGESTION W INDOW S IZE ON THE P ERFORMANCE E VA...ijwmn
A mobile ad hoc network (MANET) is a temporary coll
ection of mobile nodes randomly moved within a
limited terrain area. The nodes are connected to fo
rm a wireless network without use any communication
infrastructure. Because of the limiting resources o
f MANET nodes, multiple hops
scheme is proposed for
data exchange
across the network. Varieties of mobile ad hoc rout
ing protocols have been developed to
support the multi-hop scheme of ad hoc networks. A
popular Transmission Control Protocol (TCP)
provides a reliable connection in a computer networ
k environment; it sets its congestion window size i
n
response to the behavior of the network to achieve
the best performance. This work aims to investigate
and
compare the MANET protocol
performance, such as DSDV, AODV and DSR in terms of
network
throughput, average routing load, the packet delive
ry ratio (PDR), and average end-to-end delay by
varying the maximum congestion window size. Our si
mulation has been implemented using a well-known
NS-2.35 network simulator. The simulated results sh
ow that the demonstrates of the concepts of MANET
routing protocols with respect to TCP congestion wi
ndow size in MANET environment
Hierarchical Genetic Algorithm For Dynamic Channel Units Allocation in TD-CDM...ijwmn
Hierarchical Genetic Algorithms (HGA) as a tool for search and optimizing methodology have now reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU), is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In a cellular network, the call arrival rate, call duration and the communication overhead between the base stations and the control center are vague and uncertain, regardless of whether the criteria of concern are nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network (NN) topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA) in cellular networks. It aims to efficiently satisfy the diverse quality-of-service (QoS) requirements of multimedia traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update overhead, and shorter channel-acquisition delay than previous methods
Multi-Criterion Decision Making and Adaptation for Multi-path Video Streaming...Eswar Publications
It is suggested that multi-path routing is advantageous for applications with high traffic data characteristics, especially in the WSN environment. Sensor networks which transmit video will have to respond to the high data characteristic inherent in video data. Throughput, delay and packet loss are important metrics when considering video traffic. This work measures the performance of four multi-path routing protocols, MAOMDV, AOMDV, AntHocNet and MP-DSR in the WSN environment. It is shown that MAOMDV outperforms the other multi-path routing protocols in terms of the aforementioned metrics.
Long-Term Evolution (LTE), an emerging and promising fourth generation mobile technology, is expected
to offer ubiquitous broadband access to the mobile subscribers. In this paper, the performance of Frame
Level Scheduler (FLS), Exponential (EXP) rule, Logarithmic (LOG) rule and Maximum-Largest Weighted
Delay First (M-LWDF) packet scheduling algorithms has been studied in the downlink 3GPP LTE cellular
network. To this aim, a single cell with interference scenario has been considered. The performance
evaluation is made by varying the number of UEs ranging from 10 to 50 (Case 1) and user speed in the
range of [3, 120] km/h (Case 2). Results show that while the number of UEs and user speed increases, the
performance of the considered scheduling schemes degrades and in both case FLS outperforms other three
schemes in terms of several performance indexes such as average throughput, packet loss ratio (PLR),
packet delay and fairness index.
ACHIEVING ENHANCED THROUGHPUT IN MOBILE ADHOC NETWORK USING COLLISION AWARE M...ijasuc
Since wireless medium is high demand resource the design of an efficient medium access protocol is
important for Mobile Adhoc Networks. As MAC is the base layer in the protocol stack a performance gain
in this layer will have significant improvement in the overall performance of the network. Since the current
IEEE 802.11 MAC standard is not adaptive to the network scenario its performance is poor in terms of
throughput, fairness and delay. Although several alternatives to the existing standard is proposed many of
them are not satisfactorily address the key issues of keeping the simplicity of the protocol and avoiding the
overhead on the nodes on duty in emergency situations where usually adhoc networks are applied. In this
paper we propose an adaptive, collision aware MAC protocol for wireless adhoc networks, termed the
Collision Based Contention (CBC) protocol, in which depends on the current collision level on the shared
medium contending nodes dynamically decides its Backoff value to avoid a blind random waiting before
access to the medium. The CBC scheme outperforms the BEB scheme employed in the IEEE 802.11 MAC
standard and other competing proposals.
What is the purpose of 5G flexible duplexing?
The purpose of 5G flexible duplexing is to allow the most flexible use of an operator's spectrum for time-frequency resources in a single framework. 5G Flexible duplexing should inherently support both paired and unpaired spectrum and be forward compatible with full-duplex 5G.
A DDRESSING T HE M ULTICHANNEL S ELECTION , S CHEDULING A ND C OORDINATION...pijans
We discuss a new multichannel coordination and sche
duling challenge called the Multichannel Scheduling
Cost (MSC). It is caused by the inability of the co
ntrol channel to schedule simultaneous transmission
s
resulting in data channels lying idle and their ban
dwidth underutilized. As a result, wasted bandwidth
increases as the number of data channels increases.
To address this challenge, a cyclic scheduling
Algorithm (CSA) is proposed. It employs one dedicat
ed signaling channel and 4 data channels. It is
premised on a proactive channel reservation scheme
which reduces the idleness of channels. The scheme
ensures that data channels are reserved while they
are still busy. The data channels are reserved whil
e
their remaining transmission duration is equal to t
he virtual carrier sensing duration. This gives the
next
pair sufficient time to reserve the current data ch
annel before it becomes available, limiting the MSC
to the
first cycle. The simulation results show a performa
nce benefit of the CSA scheme in addressing the eff
ects
of the MSC
Quadrant Based DIR in CWin Adaptation Mechanism for Multihop Wireless NetworkIJCI JOURNAL
In Multihop Wireless Networks, traffic forwarding capability of each node varies according to its level of contention. Each node can yield its channel access opportunity to its neighbouring nodes, so that all the nodes can evenly share the channel and have similar forwarding capability. In this manner the wireless channel is utilized effectively, which is achieved using Contention Window Adaptation Mechanism (CWAM). This mechanism achieves a higher end-to-end throughout but consumes the network power to a higher level. So, a newly proposed algorithm Quadrant- Based Directional Routing Protocol (Q-DIR) is implemented as a cross-layer with CWAM, to reduce the total network power consumption through limited flooding and also reduce the routing overheads, which eventually increases overall network throughput. This algorithm limits the broadcast region to a quadrant where the source node and the destination nodes are located. Implementation of the algorithm is done in Linux based NS-2 simulator
QoS -Aware Spectrum Sharing for Multi-Channel Vehicular NetworkIJSRD
We consider QoS -aware band sharing in cognitive wireless networks where secondary users are allowed to access the band owned by a primary network provider. The intrusion from secondary users to primary users is forced to be below the tolerable limit. Also, signal to intrusion plus noise ratio (SINR) of each secondary user is maintained higher than a required level for QoS cover. When network load is high, admission control needs to be performed to satisfy both QoS and intrusion constraint. We propose an admission control algorithm which is performed jointly with power manage such that QoS needs of all admitted secondary users are satisfied while keeping the intrusion to primary users below the passable limit. When all secondary users can be supported at minimum rates, we allow them to increase their spread rates and share the spectrum in a fair manner. We formulate the joint power/rate allocation with max-min equality principle as an optimization problem. We show how to change it into a convex optimization problem so that its globally most favourable solution can be obtained. Numerical grades show that the proposed admission control algorithm achieves performance very close to the optimal solution.
Improved Algorithm for Throughput Maximization in MC-CDMAVLSICS Design
The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .
Channel feedback scheduling for wireless communicationseSAT Journals
Abstract Opportunistic scheduling can significantly improve wireless network performance by exploiting the underlying channel condition. There has been a lot of work on opportunistic scheduling, but the problem of finding the right feedback mechanism to convey channel information has largely been untouched. In emerging multichannel systems, the per-channel feedback induces a substantial amount of feedback overhead and requires high computational complexity. To reduce the feedback overhead, we consider an opportunistic feedback strategy that activates the channel feedback opportunistically according to the channel condition. Then, we combine the opportunistic feedback with the best-n channel feedback scheme where a mobile user chooses the best n channels and transfers this information to the base station. We analyze the throughput and the amount of channel feedback information for proportionally fair opportunistic scheduling under Rayleigh fading i.i.d. channels. The numerical results confirm that our partial feedback schemes achieve a remarkable reduction in the amount of feedback information without significant throughput degradation, thereby saving the scarce wireless bandwidth and limited battery power.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Pilot Decontamination over Time Frequency and Space Domains in Multi-Cell Ma...IJECEIAES
In this article, we show that Pilot contamination problem can be seen as a source separation problem using time, frequency, and space domains. Our method capitalizes on a nonunitary joint diagonalization of spatial quadratic time-frequency (STFD) signal representation to identify the desired and interfering users. We first compute the noise subspace from the STFD matrices selected appropriately. Secondly, we use the noise subspace obtained to estimate the Elevation (El) and the Azimuth (Az) angles for which the MUSIC cost function is maximized. Numerical simulations are provided to illustrate the effectiveness and the behavior of the proposed approach.
Effect of Channel Variations on the Spectral Efficiency of Multiuser Diversit...IDES Editor
The high spectral efficiency or high user data rates
from multiuser diversity scheme using MIMO systems with
antenna selection and MRC reception is very important
development for modern cellular communications. Usually in
a service area of such system, the channel type is assumed to
remain constant, and in a Rayleigh fading environment such
systems are found to provide the highest data rate to a scheduled
user. In a service area using multiuser diversity MIMO
technology, the users at different locations may not experience
the same channel type and hence practically observed data
rates differ from the assumed values. We present in this report
how the scheduled user data rate suffers if the channel type
deviates from Rayleigh to Nakagami-m fading in the cellular
service area, both for absolute or dedicated SNR scheduling
scheme and proportional or normalized SNR scheduling
scheme. We explore the loss of user data rates in different
received SNR regime 0 dB, 10 dB, and 20 dB, and for different
m values with different MIMO configurations. We find that at
0 dB per antenna received SNR the loss of user data rates are
the highest.
Enhanced Data rates for Global Evolution (EDGE)Ramrao Desai
Mobile users continue to demand higher data rates. With the continued growth in cellular services, laptop computer use and the Internet, wireless network providers are beginning to pay an increasing amount of attention to packet data networks. Enhanced Global Packet Radio Service (EGPRS) offers a substantial improvement in performance and capacity over existing GPRS services, in return for a relatively minimal additional investment. EGPRS, commonly called EDGE, achieves these enhancements to the GPRS system primarily by implementing changes to the Physical layer and to the Medium Access Control/Radio Link Control (MAC/RLC) layer. The significant improvements are a new modulation technique, additional modulation coding schemes, a combined Link Adaptation and Incremental Redundancy technique, re-segmentation of erroneously received packets, and a larger transmission window size.
WARM WELCOME FROM HCL VELACHERY…….
HCL Learning is part of HCL Info Systems Ltd, India’s Premier information enabling company with an annual turnover of 15000 crores Leveraging on the 34 years of industry experience of HCL, with an objective to develop quality IT professionals to meet this ever expanding requirement of Hardware Networking and Software professionals for the IT sector, HCL has launched HCL Career Development Centre.
For any clarification,
contact Person
Mr.Senthilvel.S
9382207007
HCL Velachery -42
LTE QOS DYNAMIC RESOURCE BLOCK ALLOCATION WITH POWER SOURCE LIMITATION AND QU...IJCNCJournal
3GPP has defined the long term evolution (LTE) for 3G radio access in order to maintain the future
competitiveness for 3G technology, the system provides the capability of supporting a mixture of services
with different quality of service (QoS) requirements. This paper proposes a new cross-layer scheduling
algorithm to satisfy better QoS parameters for real time applications. The proposed algorithm takes care of
allocating resource blocks (RBs) with different modulation and coding schemes (MCS) according to target
bit error rate (BER), user equipment supportable MCS, queue stability constraints and available transmit
power constraints. The proposed algorithm has been valued, compared with an earlier allocation algorithm
in terms of service rate and packet delay and showed better performance regards the real time
applications.
Clustering based Time Slot Assignment Protocol for Improving Performance in U...journal ijrtem
Recently, numerous approaches have been proposed for designing medium access control (MAC)
in underwater acoustic networks (UANs). Some of those works tried to adapt MAC protocols proposed for
terrestrial networks. However, unique environmental characteristics of UANs make the MAC protocols hard to be
used in the UANs and degrade network performance. In order to improve network performance, COD-TS MAC
protocol was proposed. COD-TS focuses on both single hop and multi-hop mode and utilizes CDMA for
exchanging schedule information between cluster heads. COD-TS has shortcomings such as collisions, additional
energy consumption by exchanging schedule information and near-far effect of CDMA. To overcome above
shortcomings, we propose a clustering-based time slot assignment protocol. In the proposed protocol, nodes are
clustered, and each cluster head performs two-hop neighbor cluster discovery operation. And then, a cluster head
obtains its own relative position information. Finally, the cluster head assigns its own time slot for data
transmission based on the information. Simulation results show that the proposed protocol has always better
performance compared to the COD-TS.
Clustering based Time Slot Assignment Protocol for Improving Performance in U...IJRTEMJOURNAL
Recently, numerous approaches have been proposed for designing medium access control (MAC)
in underwater acoustic networks (UANs). Some of those works tried to adapt MAC protocols proposed for
terrestrial networks. However, unique environmental characteristics of UANs make the MAC protocols hard to be
used in the UANs and degrade network performance. In order to improve network performance, COD-TS MAC
protocol was proposed. COD-TS focuses on both single hop and multi-hop mode and utilizes CDMA for
exchanging schedule information between cluster heads. COD-TS has shortcomings such as collisions, additional
energy consumption by exchanging schedule information and near-far effect of CDMA. To overcome above
shortcomings, we propose a clustering-based time slot assignment protocol. In the proposed protocol, nodes are
clustered, and each cluster head performs two-hop neighbor cluster discovery operation. And then, a cluster head
obtains its own relative position information. Finally, the cluster head assigns its own time slot for data
transmission based on the information. Simulation results show that the proposed protocol has always better
performance compared to the COD-TS.
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2. 36 Computer Science & Information Technology (CS & IT)
group since the MODCODmust be low to ensure the correct reception of all the packets by all
receivers.
Since more and more TV terminals are equipped with a broadband connection, a novel
Redundancy on Demand (RoD) technique was proposed recently in order to improve the
reception of terrestrial broadcast signals with the help of additional redundancy data [5].
Depending on the terminal position and quality of reception, a parallel redundancy transmission
on the broadband connection can help to increase reception quality and network coverage.
2. BROADCAST/UNICAST REPARTITION
In case of 5G, the terminals receiving a broadcast/multicast transmission also have broadband
(one to one) connections with the base station. A possible improvement would be to consider an
uplink transmission of negative acknowledgements incase the receiver does not correctly decode
the packet. This can be done by adding a Hybrid Automatic Repeat Request (HARQ) process, in
which the first transmission is not in a point-to-point mode but in a broadcast mode. Once this
broadcast detection fails,a negative acknowledge (NACK) is transmitted and the HARQ process
takes over the retransmission and decoding of this packet by using, for instance, incremental
redundancy. The advantage of this type of schemes is that the base station does not need to build
on the weakest receiver in the multicast group. It may be more advantageous to use a higher
modulation and coding scheme, even if some of the transmissions need to be repeated for only
few users.
The scheduler selects one transmission rate to satisfy the maximum number of users. However,
users near the cell edge experience bad channel quality due to power attenuation. In this case, the
scheduler can choose between two extreme cases: either to use a data rate that fits the good
channel quality cluster or to use a low data rate that can be decoded by all users, including the
ones at the cell edge. The former case excludes users at the cell edge; the latter case is inefficient
because a low data rate is imposed on all users. The goal of this paper is to find the best
compromise to maximize the delivery time.
The total time needed to deliver a correct packet to all users is given by a sum of the time needed
for the broadcast phase and the time needed for the unicast (retransmission) phase. The
retransmission time depends on the number of frequency resources allocated to the HARQ
process. For simplicity, it is assumed that the same number of resources is allocated to both the
broadcast and the HARQ components.
In an ideal scenario, where all users have the same channel quality, the base station can choose a
retransmission rate that guarantees reception for all users. As the supported data rates across users
may vary, it is difficult for the base station to find a rate that fits all users, unless it selects the
lowest rate that all users can decode. However, this penalizes users with good channel conditions
and increases the total delivery time. In this paper, we present an optimization algorithm that
selects the best data rate based on the channel qualities of the users. We also present simulation
results that show the gain in delivery time that can be obtained by using an HARQ component.
3. SYSTEM MODEL
In this manuscript, a single cell scenario using multicarrier transmissionswith Orthogonal
Frequency-Division Multiplexing (OFDM) is considered. It is assumed that mobile receivers are
located randomly within the cell. Receivers suffer both from slow fading due to attenuation and
shadowing as well as fast fading. Receivers close to the base station will have a better signal-to-
3. Computer Science & Information Technology (CS & IT)
noise ratio (SNR) than users on the cel
all user channels for each subcarrier
A mixed broadcast/multicast protocol
first broadcast step, the base station transmits a packet to all users using the same carrier (group
of adjacent subcarriers) frequency. Some users will be able to decode
positive acknowledgement (ACK), whereas some other users will not be able to decode the
packet and shall transmita NACK. In
transmitted a negative acknowledge using unicast.
(robust) MODCOD that will enable it to decode the packet after one retransmission.
It is also necessary to consider the problem of optimizing the frequency time resources used for a
complete transmission of one packet to all users.
resource (subcarrier) is used. Hence,
packet to all users. The total time is given by
Fig. 1.Mixed broadcast/multicast protocol with retransmissions.
The system selects a single MODCOD for the broadcast phase
example, if a 16QAM modulation
calculated as 4 ∙ 2.66
NACKs, the system selects a unique
the broadcast packet, thus proceed
MODCOD selected for user i results in rate
all the time but rather only a fraction
BER of a given user is 0.1 then retransmission occurs only
time is given by Eq. (2), and the total time to deliver 1 bit is given by Eq. (3).
Computer Science & Information Technology (CS & IT)
than users on the cell edge. We assume that the base station has knowledge of
all user channels for each subcarrier, for example via Channel Quality Indicators (CQI).
ulticast protocol divided into two steps is considered, as shown in
he base station transmits a packet to all users using the same carrier (group
of adjacent subcarriers) frequency. Some users will be able to decode the packet and transmit a
positive acknowledgement (ACK), whereas some other users will not be able to decode the
packet and shall transmita NACK. In a second step, the base station addresses the users that
transmitted a negative acknowledge using unicast. Each user can be addressed with a suitable
(robust) MODCOD that will enable it to decode the packet after one retransmission.
the problem of optimizing the frequency time resources used for a
packet to all users. In such case, at each time, one frequency
. Hence, this amounts to optimizing the total time to deliver a correct
packet to all users. The total time is given by Eq. (1).
broadcast/multicast protocol with retransmissions.
MODCOD for the broadcast phase, corresponding to a rate
16QAM modulation (4 bits per symbol) is used with coding rate 10/15
66 bps. In the second phase, following reception of one or more
NACKs, the system selects a unique and specific MODCOD for each user that failed to decode
proceeding to retransmit the packet in a unicast manner. The
results in rate R . For each user i, the retransmission does not occur
a fraction BER(i), where BER is the bit error rate. For example
BER of a given user is 0.1 then retransmission occurs only 10% of the time. Thus the total unicast
given by Eq. (2), and the total time to deliver 1 bit is given by Eq. (3).
37
l edge. We assume that the base station has knowledge of
for example via Channel Quality Indicators (CQI).
as shown inFig. 1. In a
he base station transmits a packet to all users using the same carrier (group
the packet and transmit a
positive acknowledgement (ACK), whereas some other users will not be able to decode the
second step, the base station addresses the users that
Each user can be addressed with a suitable
the problem of optimizing the frequency time resources used for a
, at each time, one frequency
this amounts to optimizing the total time to deliver a correct
(1)
a rate . For
is used with coding rate 10/15, the rate is
. In the second phase, following reception of one or more
MODCOD for each user that failed to decode
to retransmit the packet in a unicast manner. The
, the retransmission does not occur
. For example, if the
10% of the time. Thus the total unicast
4. 38 Computer Science & Information Technology (CS & IT)
BER( )
!"#$"
%&
∙
1
%
(2)
1
BER( )
!"#$"
%&
∙
1
%
(3)
4. PHYSICAL LAYER MODEL
The latest PHY layer specification of ATSC 3.0 [2] is used in order to calculate the BER of the
initial transmission and subsequent retransmissions. The main part of the ATSC 3.0 PHY layer is
the Bit Interleaved Coded Modulation (BICM) chain consisting of a Forward Error Correcting
(FEC) code, a bit interleaver and a constellation mapper [6, 7]. The FEC adopted in ATSC3.0 is a
Low-Density Parity Check (LDPC) code with two possible block code lengths: short code 16200
and long code 64800 [2]. In this paper, we only consider the long code case. The constellation
mapper uses the Non-Uniform Constellationsproposed in [7], whichare optimized for a particular
code rate. Bit interleavers are also optimized to achieve a very good spectral efficiency. In ATSC
3.0, coding rates from 2/15 to 13/15 with step 1/15 are used. Constellation orders to use are:
QPSK, 16QAM, 64QAM, 256QAM, 1KQAM and 4KQAM. As an example,Fig. 2 shows the
waterfall SNR performance vs. BER for a 16QAM and coding rates ranging from 5/15 to 13/15,
for AWGN channel.
Fig. 2.SNR vs. BER of ATSC3.0, for modulation size 16QAM and AWGN channel model.
From Fig. 2, it is possible to affirm that both spectral efficiency and SNR performancedepend on
the selected MODCOD. The spectral efficiency of the system ranges from 0.266 bps/Hz for
QPSK with coding rate 2/15 to 10.4bps/Hz for 4KQAM with coding rate 13/15. This range is
shown in Fig. 3.
2 3 4 5 6 7 8 9 10 11 12
SNR (dB)
10-8
10
-6
10-4
10-2
100
5/15
6/15
7/15
8/15
9/15
10/15
11/15
12/15
13/15
5. Computer Science & Information Technology (CS & IT) 39
Fig. 3.Spectral efficiency vs. SNR of ATSC3.0 chain, for AWGN channel model.
The horizontal axis represents the SNR needed to achieve a particular efficiency. This
corresponds to the waterfall (BER<10-6
) of the corresponding MODCOD. For example, it takes
around 33dB of SNR to use the MODCOD 4K with code rate 13/15.
The scheduler selects a given MODCOD for the first transmission (broadcast phase) and then a
possibly different MODCOD for each user requiring a retransmission. A high MODCOD selected
at the first phase allows the broadcast transmission time to be minimized. However, the higher the
MODCOD, the larger the number of users transmitting NACK signals. As a result, this will
increase the number of users that require a retransmission in the unicast phase. It will also
increase the BER of each user. Thus a selection of a higher MODCOD for the broadcast phase
will reduce the first term of Eq. (3),
()*
, and increase the second term ∑ BER( )!"#$"
%& ∙
(,
, both in
the number of users inside the sum and the BER that multiplies each user time. The optimization
is focused on finding the best compromise between the first and the second term. Note that the
second unicast phase is used in the time calculation but it is entirely dependent on the broadcast
MODCOD.
5. FREQUENCY-SELECTIVE CHANNELS
In the case of frequency selective channels, the scheduler responsible for implementing the mixed
broadcast/unicast protocol has two different tasks. The first task is to select the carriers to be used
for each step; and the second task is to select the MODCOD for each step. In order to select the
best set of carriers, the scheduler needs to select the best carriers across all users. This is achieved
by avoiding deep fades across any of the users, since it will limit the MODCOD used.
Fig. 4 shows an example of 3 users experiencing different fading at a given time instant. The
selection of any of the particular carriers (A, B, C) will lead to a very bad choice of modulation
and coding scheme. The best choice is to select the carrier that allows the use of the highest
possible MODCOD, in order to minimize the transmission time of the broadcast component, as
shown in Fig. 4 (D). This is achieved by taking theminimum SNR across users for each carrier,
then locating the maximum of these SNRs. This “max-min” approach for carrier selection will be
used for the first transmission. If the fading for user i at subcarrier c is defined asSNR(i,c), then
the best subcarrier to be used for the broadcast case is given by Eq. (4).
6. 40 Computer Science & Information Technology (CS & IT)
Fig. 4.Frequency selective channels of 3 users and best carrier for broadcast.
best max
2345677%87 5
9 min
3287 %
SNR( , ?)@ (4)
Depending on the expected average throughput of the broadcast content the scheduler can user
more than one carrier to deliver the content. The max-min equation can then be used in the same
way but across adjacent carriers.
6. SIMULATION RESULTS
In order to analyze the total time needed for the content delivery using the two step protocol, we
consider a single cell system where users are randomly located inside the cell. The fading
suffered by each user is composed of two components: a slow fading component related to the
attenuation (path-loss and shadowing) due to the mobile location and shadowing and a fast fading
component, due to the multipath selective channel experienced by each mobile. The slow fading
parameters are given in Table 1. A ‘pedestrian B’ channel is used for the fast fading component,
with a delay profile as defined in Table 2.
Table 1. Slow fading parameters used in the simulations.
Parameter Value
Number of subcarriers 2048
Path-loss propagation model Macro cell: urban Area [9]
Shadowing standard deviation 8
eNB Power 1 Watt
Cell Radius 1000m
MinimumUE distance from eNB 50m
Subcarrier spacing 15KHz
Thermal Noise -173 dBm
7. Computer Science & Information Technology (CS & IT) 41
Table 2. ‘Pedestrian B’ channel.
Relative Delay (ns) 0 200 800 1200 2300 3700
Power (dB) 0 -0.9 -4.9 -8.0 -7.8 -23.9
The objective is to assess the total time needed for the delivery of 1 bit/Hz and study the best
MODCOD scheme to be utilized during the broadcast step. Furthermore, we aim to find the best
compromise allowing us to minimize the overall transmission time (the sum of the broadcast and
unicast times). From Fig. 3, it is possible to affirm that spectral efficiencies of some MODCODs
are overlapping. The study can be further simplified by considering only coding rates 6/15, 7/15,
8/15, 9/15, 10/15, 11/15, 12/15, 13/15 for modulation sizes 16QAM, 64QAM, 256QAM,
1KQAM and 4KQAM. For the low modulation (QPSK) we also consider low code rates
including 2/15, 3/15, 4/15 and 5/15, since these codes are the only ones that give a very low
spectral efficiency. The study covers 52 MODCODs ranging from QPSK2/15 to 4KQAM13/15.
Fig. 5.Time per Hz to deliver 1 bit to all users in a cell with 15 users.
We start by considering a cell with 15 users suffering fading as explained above. The broadcast
time, the unicast time and the total time are depicted in Fig. 5. The total time is composed of two
components: the broadcast and unicast time, which decreases and increases with the MODCOD
respectively. The broadcast time decreases because the data rate increases with the MODCOD,
and thus the time needed to transmit a certain amount of information decreases. On the other
hand, as the MODCOD (of the broadcast phase) increases, the unicast step sees time increase.
This is due to the fact that more and more users are requesting NACKs and thus the total time
taken to service these increases. The interesting conclusion resides in the total minimum time.
From the figure, it is observed that the MODCOD 9, i.e. QPSK 10/15, guarantees the minimum
transmission time. For the unicast phase, the scheduler selects the best available carrier and uses
the best MODCOD that guarantees an error free transmission (BER curve waterfall below the
carrier SNR).
This study can be extended by evaluating the best MODCOD and the percentage of NACK
transmitting users in order to draw conclusions on which strategy to use depending on the cell
load. The results are given in Fig. 6.
0 5 10 15 20 25 30 35 40 45 50
MODCOD
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Broadcast time per Hz
Unicast time per Hz
Total time per Hz
8. 42 Computer Science & Information Technology (CS & IT)
Fig. 6.Optimal MODCOD scheme and percentage of NACK users.
The optimal MODCOD decreases as the number of users increases. This is due to the necessity to
use a more conservative approach when covering a highernumber of users. The same thing is
observed from the NACK percentage (the number of users that require retransmissions) that
decreases with the MODCOD. For lower number of users, a more aggressive approach is more
optimal as it delivers the broadcast message in a very short time using a high MODCOD. Users
that do not receive the message will be addressed by unicast. The percentage of users is high, but
since the total number of users in the cell is low, the number of users to be addressed by unicast
also remains low. This guarantees that the total sum of broadcast and unicast subsequently
remains low.
7. CONCLUSIONS
In this paper, we propose a new hybrid approach for content delivery in frequency selective
fading channels. The proposed method is based on two components: broadcast and unicast
(HARQ retransmission) components. The broadcast component is used to deliver the content to
the users in a first phase, whereas the HARQ component is used to retransmit the same packet to
users that did not receive it during the broadcast phase. The advantage of this approach is that it
frees up the scheduler from trying to select a uniquetransmission data rate for all users with some
users having bad channel qualities. We show that usinga conservative approach that serves all the
users in oncetransmission is not optimal. In order to reduce the total transmission time, there is an
optimalMODCOD for both stages. For cells with moderate numbers of users the optimal
MODCOD is in the mid-range representing the best balance between the two stages. For cells
with a high number of users a conservative approach consisting in the choice of a low MODCOD
is preferable, in order to reduce the number of users that will require retransmissions.
ACKNOWLEDGEMENTS
This work was supported in part by the European Commission under the 5GPPPproject 5G-Xcast
(H2020-ICT-2016-2 call, grant number 761498). The viewsexpressed in this contribution are
those of the authors and do not necessarily represent the project.
OptimalMODCODandNACKpercentrage
9. Computer Science & Information Technology (CS & IT) 43
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[2] L. Fay, L. Michael, D. Gomez-Barquero, N. Ammar, and W. Caldwell, “An overview of the ATSC
3.0 physical layer specification,” IEEE Transactions on Broadcasting, vol. 62, no. 1, Mar. 2016.
[3] V. Vartiainen and J. Kurjenniemi, “Point-to-multipoint multimedia broadcast multicast service
(MBMS) performance over HSDPA,” in Personal, Indoor and Mo bile Radio Communications, 2007.
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AUTHORS
Belkacem Mouhouche received his Ph.D. degree in Signal Processing from
EcoleNationaleSuperieure des Telecoms (Telecom Paristech) in France in 2005.
During his Ph.D. he worked on 3GPP third generation systems (UMTS), he later
worked as a 3GPP standard Engineer following the development of HSDPA and
LTE systems. He was also involved in FP7 European Project End to End Efficiency
(E3) where he worked on cognitive radio in heterogeneous systems. Before joining
Samsung he worked in major telecommunication companies like Sierra Wireless,
Freescale Semiconductor, NEC and Alcatel Lucent. His research interest are in the
area of advanced techniques for the physical layer of future communication systems
including MIMO, beamforming and coding applied to broadcast and broadband systems like the LTE-A
and DVB, ATSC3.0. Recently, He was heavily involved in the development of the latest broadcast
terrestrial standard ATSC3.0 and lead the broadcast activity within the 5G-PPP project Fantastic-5G.
Recently, he was appointed as innovation and dissemination manager of the 5G-PPP project 5G-Xcast
focused on new point to multipoint techniques for 5G networks.
Louis Christodoulou received his Ph.D. degree in electronic engineering from the
University of Surrey, U.K., in 2016, focussing on the development of a hybrid unicast
broadcast enhanced multimedia delivery framework over LTE. His current research
interests include multipoint transmission techniques and with experience working in
the television broadcast industry; future multimedia content delivery, mobile
broadcast, and radio resource management. He is currently a 5G Research Engineer
with Samsung Electronics Research and Development Institute, U.K. contributing to
10. 44 Computer Science & Information Technology (CS & IT)
the Horizon 2020 5GPPP European Projects such Fantastic-5G focused on 5G PHY solutions and 5G-Xcast
focused on point to multipoint solutions for 5G.
Manuel Fuentes received his M.Sc. degree in telecommunication engineering and a
second M.Sc. degree in communication technologies, systems and networks from the
Universitat Politecnica de Valencia, Spain, in 2012 and 2013, respectively. He also
obtained the Ph.D. degree in telecommunication engineering in 2017. From 2012 to
2017, he was working at the Institute of Telecommunications and Multimedia
Applications (iTEAM). He also has been a guest researcher at the Vienna University
of Technology, Austria, in 2016. He participated in several R&D projects where his
research interests were focused on interference mitigation and network planning
activities between digital broadcasting and 4G technologies. He also has contributed
actively to the ATSC 3.0 standardization process. In 2017, Dr. Fuentes joined the Samsung Electronics
R&D UK team as a 5G research engineer to participate in the 5P-PPP phase-2 project 5G-Xcast, for the
efficient delivery of broadcasting in 5G New Radio. His main research interests include physical layer
procedures, innovative techniques in bit-interleaved coding and modulation, and multi-antenna
communications