Page 35 - 2017 Brochure
P. 35
ited. In such cases, it is I/O bound that each computing node must process a data set much larger than the Research Description
size of its physical memory, which is time consuming.
Ling-Jyh Chen
In this study, we aim to enhance the MapReduce framework to support applications that require computation
of suffix arrays. We thus have two sub-goals. One is to implement a suffix-array algorithm, based on the notion for Associate Research Fellow
separation of storage and computing, to reduce the total number of processors. We will also design and develop
memory-based storage architecture to support applications to be implemented with separate storage and Meng-Chang Chen
computation.
Research Fellow
4. Wen-Tsuen Chen
Sheng-Wei Chen
The 5th generation mobile communications system (5G) has attracted much attention recently. As such, many
task groups have been established to work toward the identification of system requirements, novel system Research Fellow
concepts and potential access technologies for 2020 and beyond. In order to produce a functional 5G network,
we must overcome major challenges with regard to explosive growth of mobile data traffic volume, number of Wen-Tsuen Chen
connected devices, and typical end user data rate.
Distinguished Research Fellow
In future 5G networks, the deployment of ultra-dense smallcell networks is a feasible and reasonable solution
for enhancing spectrum utilization to meet 5G requirements. Toward management of 5G networks, software- Tyng-Ruey Chuang
defined networking (SDN) decouples the software defined control plane from the hardware driven data plane on
general purpose hardware. Because there is an increasing trend towards implementing more functions of mobile Associate Research Fellow
communications systems in software, SDN will be an essential strategy for 5G management.
Jan-Ming Ho
Many challenges and problems in 5G networks still need to be resolved. We focus on mobility and resource
management mechanisms in SDN-based ultra-dense smallcell networks to seek possible solutions. In the mobility Research Fellow
management aspect, we study the intra-domain and inter-domain handover procedures in an SDN-based ultra-
dense smallcell network. Moreover, we consider both the handover decision and group mobility issues. In the Jane W. S. Liu
resource management aspect, we explore advanced techniques for improving the network throughput, such as
massive MIMO, CR, CoMP, etc. Finally, we also take the fairness and QoS guarantee into account.. Distinguished Visiting Chair
5. Wen-Tsuen Chen 33
We perform research in the field of next-generation cellular networks, known as 5G networks, which employ
technologies such as Software-Defined Network (SDN), Network Function Virtualization (NFV), Internet of Things
(IoT), and Massive MIMO. Our research objectives include traffic engineering, resource optimization, and security
in a promising network architecture.
Current traffic engineering in SDN is mostly accomplished with unicast methods. By contrast, multicast can
effectively reduce network resources consumption to jointly serve multiple clients. We investigate a reliable
multicast tree for SDN to minimize both multicast and recovery costs for reliable multicast transmission. We also
study multicast traffic engineering for multiple trees, which is very challenging because we must jointly consider
the bandwidth consumption minimization of a single multicast tree, the link capacity for flows, and the node
capacity for storing the forwarding entries in Group Table. In addition traffic engineering, there are inherent benefits
to incorporating SDN and NFV in the next-generation cellular network, particularly for the management and
orchestration of VNFs. We design a scheme of service chain embedding to maximize the total amount of flows,
while bounding the process overhead of the flows on a node, by its computation capability. The total amount of
flows is on a link by its bandwidth capacity. Furthermore, most previous studies on NFV focus on unicast service
chains and thereby are not scalable to support a large number of destinations in multicast. We make the first
attempt to tackle the new, and challenging problem of constructing a service tree that contains multiple branching
service chains required by each destination.
Moreover, we also study several security issues in SDN/NDF architecture. Deep packet filtering (DPF) has
been demonstrated to be an essential technique for effective fine-grained access controls, but it is commonly
recognized that the technique may invade the individual privacy of the users. Fortunately, secure computation can
address the tradeoff between privacy and DPF functionality. However, the current solutions limit the scalability of
the network due to the intensive computation overheads and large connection setup delay. We propose a privacy-
preserving deep packet filtering protocol that can efficiently perform filtering functions on encrypted traffic while
decreasing the communication overhead and setup delay for the controller in SDN. In order to mitigate HTTP
DDoS attacks, shuffling-based moving target defense redirects user traffic among a group of virtualized service
functions and has been regarded as one of the most effective strategies. Nevertheless, previous work did not note
that frequent changes of user traffic will significantly intensify the control overhead of SDN. Therefore, we have
developed a cost-effective shuffling-based defense system with a guaranteed performance bound.
The number of Internet of Things (IoT) devices is rapidly increasing and has become quite extensive. Thus, the
IEEE 802.11ah standard adopts the grouping-based MAC protocol to reduce the contention overhead of each
group of devices. However, most existing designs randomly assign devices to groups, and little attention has
been paid to the problem of forming efficient groups. We propose a load-balanced grouping algorithm to improve
channel utilization for each group. In addition, Multi-User Multiple Input Multiple Output (MUMIMO) enables a
multi-antenna access point (AP) to serve multiple users simultaneously, and has been adopted as the IEEE
802.11ac standard. In practice, user frames with heterogeneous lengths may cause the concurrent transmission
opportunities to become incompletely utilized. To resolve this inefficiency, we present a PHY-MAC design that adds
additional frames to fill up the idle channel time and better utilize the spatial multiplexing gain. On the other hand,
IoT services may be associated with burst traffic, critical tasks, and low latency requirements. To this end, we
propose to utilize idle devices in IoT networks to boost the transmission data rate for critical tasks through multiple
concurrent transmissions. Furthermore, we also study the specific applications of IoT. For example, wireless
surveillance in cellular networks has become increasingly important. We design an efficient method to minimize
the number of allocated resource blocks (RBs) while guaranteeing the coverage requirement for surveillance
systems in uplink networks.
size of its physical memory, which is time consuming.
Ling-Jyh Chen
In this study, we aim to enhance the MapReduce framework to support applications that require computation
of suffix arrays. We thus have two sub-goals. One is to implement a suffix-array algorithm, based on the notion for Associate Research Fellow
separation of storage and computing, to reduce the total number of processors. We will also design and develop
memory-based storage architecture to support applications to be implemented with separate storage and Meng-Chang Chen
computation.
Research Fellow
4. Wen-Tsuen Chen
Sheng-Wei Chen
The 5th generation mobile communications system (5G) has attracted much attention recently. As such, many
task groups have been established to work toward the identification of system requirements, novel system Research Fellow
concepts and potential access technologies for 2020 and beyond. In order to produce a functional 5G network,
we must overcome major challenges with regard to explosive growth of mobile data traffic volume, number of Wen-Tsuen Chen
connected devices, and typical end user data rate.
Distinguished Research Fellow
In future 5G networks, the deployment of ultra-dense smallcell networks is a feasible and reasonable solution
for enhancing spectrum utilization to meet 5G requirements. Toward management of 5G networks, software- Tyng-Ruey Chuang
defined networking (SDN) decouples the software defined control plane from the hardware driven data plane on
general purpose hardware. Because there is an increasing trend towards implementing more functions of mobile Associate Research Fellow
communications systems in software, SDN will be an essential strategy for 5G management.
Jan-Ming Ho
Many challenges and problems in 5G networks still need to be resolved. We focus on mobility and resource
management mechanisms in SDN-based ultra-dense smallcell networks to seek possible solutions. In the mobility Research Fellow
management aspect, we study the intra-domain and inter-domain handover procedures in an SDN-based ultra-
dense smallcell network. Moreover, we consider both the handover decision and group mobility issues. In the Jane W. S. Liu
resource management aspect, we explore advanced techniques for improving the network throughput, such as
massive MIMO, CR, CoMP, etc. Finally, we also take the fairness and QoS guarantee into account.. Distinguished Visiting Chair
5. Wen-Tsuen Chen 33
We perform research in the field of next-generation cellular networks, known as 5G networks, which employ
technologies such as Software-Defined Network (SDN), Network Function Virtualization (NFV), Internet of Things
(IoT), and Massive MIMO. Our research objectives include traffic engineering, resource optimization, and security
in a promising network architecture.
Current traffic engineering in SDN is mostly accomplished with unicast methods. By contrast, multicast can
effectively reduce network resources consumption to jointly serve multiple clients. We investigate a reliable
multicast tree for SDN to minimize both multicast and recovery costs for reliable multicast transmission. We also
study multicast traffic engineering for multiple trees, which is very challenging because we must jointly consider
the bandwidth consumption minimization of a single multicast tree, the link capacity for flows, and the node
capacity for storing the forwarding entries in Group Table. In addition traffic engineering, there are inherent benefits
to incorporating SDN and NFV in the next-generation cellular network, particularly for the management and
orchestration of VNFs. We design a scheme of service chain embedding to maximize the total amount of flows,
while bounding the process overhead of the flows on a node, by its computation capability. The total amount of
flows is on a link by its bandwidth capacity. Furthermore, most previous studies on NFV focus on unicast service
chains and thereby are not scalable to support a large number of destinations in multicast. We make the first
attempt to tackle the new, and challenging problem of constructing a service tree that contains multiple branching
service chains required by each destination.
Moreover, we also study several security issues in SDN/NDF architecture. Deep packet filtering (DPF) has
been demonstrated to be an essential technique for effective fine-grained access controls, but it is commonly
recognized that the technique may invade the individual privacy of the users. Fortunately, secure computation can
address the tradeoff between privacy and DPF functionality. However, the current solutions limit the scalability of
the network due to the intensive computation overheads and large connection setup delay. We propose a privacy-
preserving deep packet filtering protocol that can efficiently perform filtering functions on encrypted traffic while
decreasing the communication overhead and setup delay for the controller in SDN. In order to mitigate HTTP
DDoS attacks, shuffling-based moving target defense redirects user traffic among a group of virtualized service
functions and has been regarded as one of the most effective strategies. Nevertheless, previous work did not note
that frequent changes of user traffic will significantly intensify the control overhead of SDN. Therefore, we have
developed a cost-effective shuffling-based defense system with a guaranteed performance bound.
The number of Internet of Things (IoT) devices is rapidly increasing and has become quite extensive. Thus, the
IEEE 802.11ah standard adopts the grouping-based MAC protocol to reduce the contention overhead of each
group of devices. However, most existing designs randomly assign devices to groups, and little attention has
been paid to the problem of forming efficient groups. We propose a load-balanced grouping algorithm to improve
channel utilization for each group. In addition, Multi-User Multiple Input Multiple Output (MUMIMO) enables a
multi-antenna access point (AP) to serve multiple users simultaneously, and has been adopted as the IEEE
802.11ac standard. In practice, user frames with heterogeneous lengths may cause the concurrent transmission
opportunities to become incompletely utilized. To resolve this inefficiency, we present a PHY-MAC design that adds
additional frames to fill up the idle channel time and better utilize the spatial multiplexing gain. On the other hand,
IoT services may be associated with burst traffic, critical tasks, and low latency requirements. To this end, we
propose to utilize idle devices in IoT networks to boost the transmission data rate for critical tasks through multiple
concurrent transmissions. Furthermore, we also study the specific applications of IoT. For example, wireless
surveillance in cellular networks has become increasingly important. We design an efficient method to minimize
the number of allocated resource blocks (RBs) while guaranteeing the coverage requirement for surveillance
systems in uplink networks.
