103 research outputs found
Rate Constrained Random Access over a Fading Channel
In this paper, we consider uplink transmissions involving multiple users
communicating with a base station over a fading channel. We assume that the
base station does not coordinate the transmissions of the users and hence the
users employ random access communication. The situation is modeled as a
non-cooperative repeated game with incomplete information. Each user attempts
to minimize its long term power consumption subject to a minimum rate
requirement. We propose a two timescale stochastic gradient algorithm (TTSGA)
for tuning the users' transmission probabilities. The algorithm includes a
'waterfilling threshold update mechanism' that ensures that the rate
constraints are satisfied. We prove that under the algorithm, the users'
transmission probabilities converge to a Nash equilibrium. Moreover, we also
prove that the rate constraints are satisfied; this is also demonstrated using
simulation studies
SDN based Control and Management of WLANs in the 3GPP 5G Network
The exponential growth in mobile broadband usage [1] has catalyzed the need
for high data rate communication systems. In this regard, activities for
standardizing the next generation mobile broadband system, known as the Fifth
Generation(5G) system are underway. The 5G system also enables the integration
of Institute of Electrical and Electronic Engineers (IEEE) Wireless Local Area
Networks (WLANs) for providing cost-effective broadband connectivity. It is
therefore imperative to find solutions for control and management of WLANs,
while providing seamless inter-working capabilities with the cellular network.
In this paper, we propose a novel Software Defined Networking (SDN) based
architecture for efficient control and management of IEEE WLANs while providing
a mechanism for smooth integration of WLANs within the 5G system
Entropy-optimal Generalized Token Bucket Regulator
We derive the maximum entropy of a flow (information utility) which conforms
to traffic constraints imposed by a generalized token bucket regulator, by
taking into account the covert information present in the randomness of packet
lengths. Under equality constraints of aggregate tokens and aggregate bucket
depth, a generalized token bucket regulator can achieve higher information
utility than a standard token bucket regulator. The optimal generalized token
bucket regulator has a near-uniform bucket depth sequence and a decreasing
token increment sequence.Comment: 6 pages (2 column, 10-point), 3 figures, 1 tabl
Performance and Energy Conservation of 3GPP IFOM Protocol for Dual Connectivity in Heterogeneous LTE-WLAN Network
For the 5th Generation (5G) networks, Third Generation Partnership Project
(3GPP) is considering standardization of various solutions for traffic
aggregation using licensed and unlicensed spectrum, to meet the rising data
demands. IP Flow Mobility (IFOM) is a multi access connectivity
solution/protocol standardized by the Internet Engineering Task force (IETF)
and 3GPP in Release 10. It enables concurrent access for an User Equipment (UE)
to Heterogeneous Networks (HetNets) such as Long Term Evolution (LTE) and IEEE
802.11 Wireless Local Area Network (WLAN). IFOM enabled UEs have multiple
interfaces to connect to HetNets. They can have concurrent flows with different
traffic types over these networks and can seamlessly switch the flows from one
network to the other. In this paper, we focus on two objectives. First is to
investigate the performance parameters e.g. throughput, latency, tunnelling
overhead, packet loss, energy cost etc. of IFOM enabled UEs (IeUs) in HetNets
of LTE and WLAN. We have proposed a novel mechanism to maximize the throughput
of IeUs achieving a significant throughput gain with low latency for the IeUs.
We have explored further and observed a throughput energy trade off for low
data rate flows. To address this, we also propose a smart energy efficient and
throughput optimization algorithm for the IeUs, resulting in a substantial
reduction in energy cost, while maintaining the high throughput at lower
latency and satisfying the Quality of Service (QoS) requirements of the IeUs.Comment: 12 pages, 15 figures, journa
Connecting the Unconnected: Towards Frugal 5G Network Architecture and Standardization
This article adopts a holistic approach to address the problem of poor
broadband connectivity in rural areas by suggesting a novel wireless network
architecture, also called the "Frugal 5G Network". To arrive at the Frugal 5G
Network architecture, we take into consideration the rural connectivity needs
and the characteristics specific to rural areas. As part of the proposed Frugal
5G Network, we define a heterogeneous Access Network wherein macro cells
provide a carpet coverage while Wireless Local Area Networks (WLANs) provide
additional capacity to serve the village clusters. WLAN is backhauled via a
wireless network also called the wireless middle mile network. We define a
Software Defined Networking (SDN) and Network Function Virtualization (NFV)
based architecture to make the network flexible and scalable. The concepts of
Fog computing have also been employed in the network architecture to bring
intelligence to the edge, i.e., to the access network. Through a novel
amalgamation of these technologies, we are able to address the connectivity
requirements of rural areas. The proposed network architecture can serve as a
potential solution towards IEEE P2061, a standardization project that aims to
design an architecture to facilitate rural broadband communication
Multi-Player Multi-Armed Bandit Based Resource Allocation for D2D Communications
Device-to-device (D2D) communications is expected to play a significant role
in increasing the system capacity of the fifth generation (5G) wireless
networks. To accomplish this, efficient power and resource allocation
algorithms need to be devised for the D2D users. Since the D2D users are
treated as secondary users, their interference to the cellular users (CUs)
should not hamper the CU communications. Most of the prior works on D2D
resource allocation assume full channel state information (CSI) at the base
station (BS). However, the required channel gains for the D2D pairs may not be
known. To acquire these in a fast fading channel requires extra power and
control overhead. In this paper, we assume partial CSI and formulate the D2D
power and resource allocation problem as a multi-armed bandit problem. We
propose a power allocation scheme for the D2D users in which the BS allocates
power to the D2D users if a certain signal-to-interference-plus-noise ratio
(SINR) is maintained for the CUs. In a single player environment a D2D user
selects a CU in every time slot by employing UCB1 algorithm. Since this
resource allocation problem can also be considered as an adversarial bandit
problem we have applied the exponential-weight algorithm for exploration and
exploitation (Exp3) to solve it. In a multiple player environment, we extend
UCB1 and Exp3 to multiple D2D users. We also propose two algorithms that are
based on distributed learning algorithm with fairness (DLF) and kth-UCB1
algorithms in which the D2D users are ranked. Our simulation results show that
our proposed algorithms are fair and achieve good performance.Comment: 10 page
Performance Evaluation of Optimal Radio Access Technology Selection Algorithms for LTE-WiFi Network
A Heterogeneous Network (HetNet) comprises of multiple Radio Access
Technologies (RATs) allowing a user to associate with a specific RAT and steer
to other RATs in a seamless manner. To cope up with the unprecedented growth of
data traffic, mobile data can be offloaded to Wireless Fidelity (WiFi) in a
Long Term Evolution (LTE) based HetNet. In this paper, an optimal RAT selection
problem is considered to maximize the total system throughput in an LTE-WiFi
system with offload capability. Another formulation is also developed where
maximizing the total system throughput is subject to a constraint on the voice
user blocking probability. It is proved that the optimal policies for the
association and offloading of voice/data users contain threshold structures.
Based on the threshold structures, we propose algorithms for the association
and offloading of users in LTE-WiFi HetNet. Simulation results are presented to
demonstrate the voice user blocking probability and the total system throughput
performance of the proposed algorithms in comparison to another benchmark
algorithm
Resource Allocation for D2D Communications with Partial Channel State Information
Enhancement of system capacity is one of the objectives of the fifth
generation (5G) networks in which device-to-device (D2D) communications is
anticipated to play a crucial role. This can be achieved by devising efficient
resource allocation strategies for the D2D users. While most of the works in
resource allocation assume full knowledge of the channel states, transmitting
it in every time slot reduces the system throughput due to extra control
overhead and leads to wastage of power. In this paper, we address the problem
of D2D resource allocation with partial channel state information (CSI) at the
base station (BS) and ensure that the interference from the D2D users do not
jeopardize the communications of cellular users (CUs). With partial CSI,
existing algorithms determine the Nash equilibrium in a distributed manner,
whose inefficiency in maximizing the social utility is well known as the
players try to maximize their own utilities. This is the first work in the D2D
resource allocation field in which within a game theoretic framework, an
optimal D2D resource allocation algorithm is proposed which maximizes the
social utility of the D2D players such that a social optimum is attained. Each
D2D player with the help of the BS learns to select the optimal action. We
consider the channel to exhibit path loss. Next, we consider both a slow and
fast fading with CU mobility and propose two heuristic algorithms. We validate
the performance of our proposed algorithms through simulation results
A Framework for Wireless Broadband Network for Connecting the Unconnected
A significant barrier in providing affordable rural broadband is to connect
the rural and remote places to the optical Point of Presence (PoP) over
distances of few kilometers. A lot of work has been done in the area of long
distance Wi-Fi networks. However, these networks require tall towers and high
gain (directional) antennas. Also, they work in the unlicensed band which has
Effective Isotropically Radiated Power (EIRP) limit (e.g. 1 W in India) which
restricts the network design. In this work, we propose a Long Term
Evolution-Advanced (LTE-A) network operating in TV UHF to connect the remote
areas to the optical PoP. In India, around 100 MHz of TV UHF band IV (470-585
MHz) is unused at any location and can be put to an effective use in these
areas. We explore the idea of multi-hop topology for the proposed network. We
also compare the performance of the multi-hop network with the Point to
Multipoint (PMP) topology. The results show that multi-hop network performs
much better than the PMP network. We then formulate a Linear Programming (LP)
problem of generating optimal topology and compare its performance with the
multi-hop network. Overall, the analysis implies that an optimally planned
LTE-A network in TV UHF band can be a potential solution for affordable rural
broadband
Power Efficient Scheduling under Delay Constraints over Multi-user Wireless Channels
In this paper, we consider the problem of power efficient uplink scheduling
in a Time Division Multiple Access (TDMA) system over a fading wireless
channel. The objective is to minimize the power expenditure of each user
subject to satisfying individual user delay. We make the practical assumption
that the system statistics are unknown, i.e., the probability distributions of
the user arrivals and channel states are unknown. The problem has the structure
of a Constrained Markov Decision Problem (CMDP). Determining an optimal policy
under for the CMDP faces the problems of state space explosion and unknown
system statistics. To tackle the problem of state space explosion, we suggest
determining the transmission rate of a particular user in each slot based on
its channel condition and buffer occupancy only. The rate allocation algorithm
for a particular user is a learning algorithm that learns about the buffer
occupancy and channel states of that user during system execution and thus
addresses the issue of unknown system statistics. Once the rate of each user is
determined, the proposed algorithm schedules the user with the best rate. Our
simulations within an IEEE 802.16 system demonstrate that the algorithm is
indeed able to satisfy the user specified delay constraints. We compare the
performance of our algorithm with the well known M-LWDF algorithm. Moreover, we
demonstrate that the power expended by the users under our algorithm is quite
low.Comment: 14 pages, 14 figure
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