International Journal of Engineering Science Invention Research & Development; Vol. IV, Issue II, AUGUST 2017
www.ijesird.com, E-ISSN: 2349-6185
PERFORMANCE EVALUATION OF DATA
OFFLOADING APPROACHES FOR MOBILE
SOCIAL NETWORKS
Pagadala venkata subba reddy1, prof.Y.V Bhaskara2
M.Tech (DECS) , Department of ECE, QIS College of Engineering and Technology, (AUTONOMOUS) JNTUK,
Vengemukkalapalem Pondur road, Ongole- 523272, AP
Pvsreddy05@gmail.com
Abstract: Mobile networks are in front of strict traffic overloads
suitable to the propagation of tidy handheld devices and transfer
ravenous applications. This tries to offload the cellular network
traffic through Opportunistic Communications and Social
Participation formed by the short-range communication
technologies in the smart phones (e.g., Wi-Fi, Bluetooth). We
plan an improved Greedy algorithm used for object locate choice
Problem. Our design enables to select the most active, fixed
located and having more energy mobile nodes into the Targetset, which affect the more number of infected users. Our
simulation grades demonstrate to facilitate quantity of node
enclosed by improved Greedy algorithm is 89% and Greedy
algorithm is 76%. We are able to achieve the rate of success
information delivery over the networks in improved Greedy and
Greedy algorithms are 71% and 53% respectively. The
simulations and numerical results verify that our proposed crosslayer resource allocation can efficiently support diverse QoS
requirements over wireless relay networks.the scheduling
algorithm at the medium access control (MAC) layer for multiple
connections with diverse QoS requirements.
I. INTRODUCTION
In recent years, the demand for mobile
broadband services in cellular networks has
increased rapidly, especially in video streaming and
content sharing. The EU FP7 project METIS has
provided several key quantitative performance
indicators for 5G networks, 1,000 times higher
mobile data volume per area and 10 Gbps peak data
rate are included. In addition, the new wireless
broadband communication services, including ebanking, e-health and e-learning will be integrated
in future everyday life. Therefore, the future 5G
network should be designed towards a highly
integrated system to meet the predicted data traffic
growth and these various requirements. Not only
traditional network optimization technologies
should be utilized, such as interference management
and cooperative communication, but also new
upcoming solutions will be of great importance,
Pagadala venkata subba reddy and prof.Y.V Bhaskara
e.g., network densification, user-behaviour study
cognitive networks. Software-defined networking
(SDN), and intelligent wireless backhauling.
Caching at the network edge has become an
important means of offloading the traffic and
tackling the backhaul bottleneck in order to reduce
the latency of services and the cost of the cellular
network. In single-tier networks it has been shown
that the backhaul capacity and the size of cache
have a significant impact on the energy efficiency.
In heterogeneous networks, much work has been
done on content caching using various algorithms
and schemes. A framework to model heterogeneous
cellular networks has been built with the aid of a
factor
graph,
where
distributed
caching
optimization algorithms are designed and compared
in. In a coded caching scheme is proposed to enable
content pre-fetching prior to knowing user demands
based on the YouTube dataset. Proactively pushes
popular content to the relays and users with caching
ability via broadcasting. However, the power
consumption and the backhaul limitation of the
network are not negligible for future 5G.
II. EXISTING SYSTEM
The WMRN where a base station (BS) with
K first-in first-out (FIFO) data queues transmit to
K corresponding users with the aid of an AaF1
relay. In our cross-layer scheduling policy to be
described in Section III), a single user with the
largest weighted SNR is scheduled for transmission
in each scheduling opportunity. We assume
independent non identically distributed block
Rayleigh fading in the two hop relay links with a
coherence time of Tc seconds.
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International Journal of Engineering Science Invention Research & Development; Vol. IV, Issue II, AUGUST 2017
www.ijesird.com, E-ISSN: 2349-6185
A. MAC LAYER ARCHITECTURE
The BS has K finite queues with buffer size
B, each corresponding to a distinct user. A user’s
packet is lost if the buffer for the queue is full and a
new packet arrives. The arrival process of the
packets for each queue is assumed to be a
homogeneous Poisson process with rate λk, k = 1. .
. K, where each k corresponds to a different queue.
The probability that n packets arrive in an interval
of time T for the k-th user is then given by
Packets can be re-requested with the caveat that the
arrival of the re-requested packet is consistent with
the Poisson arrival process. The transmission time T
is the same for all users. Prior to Section VI, we
assume that the queues are backlogged such that at
least one packet is always available. As a result, the
BS is never silent. This assumption is also made in.
We relax this restriction in Section VI where we
derive the PMF of the buffer state and the PLP due
to buffer overflow.
B. PHYSICAL LAYER ARCHITECTURE
The BS and the relay each transmit for T/2
seconds in half duplex mode such that the total
transmission time from the BS to the scheduled user
is T seconds, where T ≤ Tc. The transmission time
is chosen such that the BS has knowledge of both
the BS-relay and relay-user links for scheduling
purposes. In the BS-relay link, the received signal
at the relay is given by
where ES is the transmit power at the
source, hSR is the Rayleigh fading channel
coefficient between the source and the relay, x is
the transmitted symbol using binary phaseshift
keying (BPSK), quadrature phase-shift keying
(QPSK) or M-ary pulse amplitude modulation (MPAM), and zR is the additive white Gaussian noise
(AWGN) with one-sided power spectral density N0.
In the relay-to-user link, the received signal at the
scheduled user, denoted by k=∈ {1, . . .,K}, is
given by
Pagadala venkata subba reddy and prof.Y.V Bhaskara
Set c = 1 for the case where noise power is
included in the relay amplification factor and we set
c = 0 for the case where the noise power is ignored.
The end-to-end SNR of the scheduled user is
written as
where γSR is the instantaneous SNR in the
source-to-relay link and γRk∗ is the instantaneous
SNR in the relay-touser link. We incorporate the
effect of path loss into the instantaneous SNRs such
that γSR = d –η S ES|hSR|2/N0 and γRk∗ = d –η R
ER|hRk∗ |2/N0,
C. PROPOSED CROSS-LAYER SCHEDULING
POLICY
The scheduling policy selects the user with
the largest weighted SNR of the second hop. The
weight is a function of the DPS. packet can only be
scheduled at the front of a user’s queue. As a result,
only delays of the packets at the front of each user’s
queue are required for our scheduler’s
computations. The header size of each packet can
then be significantly reduced in long queues
compared with the scheme in as time stamps with a
small number of bits are sufficient. The reduction is
due to the impact of the large variation in total
packet delay on the scheme in caused by the
dependence on the number of packets in the queue
when the packet arrives.
D. NORMALIZED SERVICE RATE
First derive the average normalized service
rate for the k-th user, i.e., the probability that the kth user is scheduled. Denote Pk(s) as the normalized
service rate when the users’ queue states are the
elements of the state vector s = [s1. . . sK]T , where
each sk, k = 1, . . . , K denotes the number of
scheduling opportunities that the packet for user k
has been waiting at the front of the queue. The
normalized service rate for user k in state s, Pk(s),
E. DELAY IN PACKET SCHEDULING
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International Journal of Engineering Science Invention Research & Development; Vol. IV, Issue II, AUGUST 2017
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Next, we derive the statistics of the DPS.
We require the probability that the current state
vector is s. Denote s(n) as the state vector after n
transmission slots. The state vectors then form a
Markov chain as Pr(s(n)|s(1), . . . , s(n − 1)) =
Pr(s(n)|s(n − 1)). We note that the transition
probability from state s(n − 1) to state s(n) when
user k is scheduled is given by Pk(s(n−1)). Hence,
the scheduler forms a K-dimensional Markov chain
with a countably infinite state space. In general, the
required eigen value equation is intractable and it is
not possible to obtain closed form expressions. the
steady state characteristics by truncating the
Markov chain and forming a 1-dimensional Markov
chain with an augmented transition matrix. This
technique for approximating the K-dimensional
Markov chain is known as generating the
augmented Markov chain. It has been well-studied
and used in several applications such as.That the
approximation is accurate.
F. SYMBOL ERROR PROBABILITY
The SEP of the scheduled user for different
modulation formats can be evaluated according to
PS = a 2_bπ_ ∞ 0 −1 2 e –b F eq ( ) d . The
constants a and b are modulation-specific with a =
1, b = 1 for BPSK, a = 1, b = 0.5 for QPSK, and a =
2(M − 1)/M, b = 3/_M2 − 1_ for M-PAM.
We note that is absolutely convergent. As
such, we can swap the sum in Theorem 1 and the
integral in applying the dominated convergence
theorem. This ensures that the infinite sum
converges. The integral can then be evaluated
efficiently using numerical integration, leading to
reduced evaluation time compared with Monte
Carlo simulation.
G. PACKET LOSS PERFORMANCE
In this section, we analyze the PLP of each
queue using the proposed scheduling policy. This is
achieved by constructing a new Markov chain for
the buffer states for each queue with transition
probabilities dependent on the scheduling policy,
arrival rate, and transmission time.
H. BUFFER STATE
Pagadala venkata subba reddy and prof.Y.V Bhaskara
We first obtain the PMF of the buffer state
that gives the probability that the buffer has l, 0 ≤ l
≤ B packets. We note that the buffer state is
measured at the beginning of a scheduling slot, after
a packet is scheduled in the current slot, and before
new arrivals. This is important as the time when the
buffer state is measured affects the PMF of the
buffer state and subsequently the PLP. We also note
that the buffer state is independent of the DPS
corresponding to user k. To calculate the PMF of
the buffer state, we require the average probability
that user k is scheduled, which is given by Pk
=∞_sn=1 n=1,...,K Pk(s)πs
I. PACKET LOSS PROBABILITY
The PLP is the probability that a packet is
lost due to buffer overflow. Before evaluating the
PLP for a given packet, The PLP for each user can
now be obtained for a given buffer size by
considering the probability that the buffer is full at
time 0 < t < T after a scheduling opportunity. Here,
t is the the time of the new packet arrival. Theorem
2 gives an approximation of the PLP. The
approximation arises due to dependence on the
stationary distribution and is exact when the
scheduling policy weights are fixed constants.
The PLP approximation shows the clear
dependence on the the transmission time and arrival
rates for the user under consideration. Intuitively, if
the arrival rate is high or the transmission time
long, the PLP due to buffer overflow is large. We
will see in Section VII-C that a consequence of this
is that additional redundancy through channel
coding does not always improve the throughput.
We note that the expected total packet delay can be
obtained via Little’s law from the buffer state
distribution and the PLP. In particular, we have
E[Wk] = Lk/λe,k,
J. TRANSMISSION TIME
That increasing the transmission time
impacts on the PLP. To determine the optimal
transmission time, the effect of channel coding
must be accounted for. Of course, when employing
coding, a longer transmission time is required to
account for the redundancy in the signal. To
examine the trade off between the coded SEP of the
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scheduled user and the PLP for each queue we
consider the throughput given by
Throughput = (1 − PE,coded)(1 − PL,ave),
where PE,coded is the coded SEP of the scheduled
user and PL,ave is the average PLP over all queues.
The average PLP Throughput R−1 = T×T unc−1
Tunc= 2 ms, Tunc= 1 ms Tunc=0.5 ms
The throughput of an equivalent single user
network versus the inverse of the code rate R−1 for
varying uncoded transmission times Tunc, arrival
rate λk = 0.1 ms−1, k = 1, 2, 3, and scheduling
policy (W1 = e0.2s1, W2 = e0.1s2, W3 = 1) over all
the queues is given by
PL,ave =1 K_K i=1 PL,i.
The throughput expression in approximates
the WMRN as a single point-to-point link using a
single queue with a PLP given by the average over
all queues. As a result, gives a simple
characterization of a WMRN as transmission times
are varied. The throughput is compared to the
inverse of the code rate R−1, for varying uncoded
transmission time Tunc. Here T = TuncR−1, where
R is the normalized rate.
Figure 1 Network topology
A. NETWORK CONFIGURATION
Figure 2.1 illustrates the wireless network
topology under consideration. Multiple subscriber
stations (SS) are connected to the base station (BS)
or relay station over wireless channels, where
multiple connections (sessions, flows) can be
supported by each SS.
III. PROPOSED SYSTEM
Traditional schedulers for wire line
networks only consider traffic and queuing status;
however, channel capacity in wireless networks is
time varying due to multipath fading and Doppler
effects. Even if large bandwidth is allocated to a
certain connection, the prescribed delay or
throughput performance may not be satisfied, and
the allocated bandwidth is wasted when the wireless
channel experiences deep fades. An overview of
scheduling techniques for wireless networking can
be found in where a number of desirable features
have been summarized, and many classes of
schedulers have been compared on the basis of
these features. To schedule wireless resources (such
as bandwidth and power) efficiently for diverse
QoS guarantees, the interactive queuing behaviour
induced by heterogenous traffic as well as the
dynamic variation of wireless channel should be
considered in scheduler design
Pagadala venkata subba reddy and prof.Y.V Bhaskara
Figure 2 Wireless links from BS to SS.
This kind of star topology is not only
applicable to cellular networks but is also used to
describe the connections between each relay station
and multiple SS in mobile ad hoc networks and
wireless sensor networks. All connections
communicate with the BS using time division
multiplexing/time-division multiple access (TDM/
TDMA). We will focus on the downlink here,
although our results can be extended to the uplink
as well. The wireless link of each connection from
the BS to each SS is depicted in Fig. 2. A buffer is
implemented at the BS for each connection and
operates in a first-input-first-output (FIFO) mode.
The AMC controller follows the buffer at the BS
(transmitter), and the AMC selector is implemented
at the SS (receiver). At the PHY, multiple
transmission modes are available to each user.
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B. THE PACKET AND FRAME STRUCTURES.
1) At the MAC, each packet contains a fixed
number of bits Nb, which include packet header,
payload, and cyclic redundancy check (CRC) bits.
After modulation and coding with mode n of rate
Rn as in Table I, each packet is mapped to a symbol
block containing Nb/Rn symbols.
2) At the PHY, the data are transmitted frame by
frame through the wireless channel, with each
frame containing a fixed number of symbols Ns.
Given a fixed symbol rate, the frame duration Tf (in
seconds) is constant and represents the time unit
throughout this paper. With TDM, each frame is
divided into Nc + Nd time slots, where for
convenience we let each time slot contain a fixed
number of 2Nb/R1 symbols. As a result, each time
slot can transmit exactly 2Rn/R1 packets with
transmission mode n. For the TM in particular, one
time slot can accommodate 2R1/R1 = 2 packets
with mode n = 1, 2R2/R1 = 3 packets with mode n
= 2, and so on. The Nc time slots contain control
information and pilots. The Nd time slots convey
data, which are scheduled to different connections
dynamically. Each connection is allocated a certain
number of time slots during each frame.
C. QOS ARCHITECTURE AT THE MAC
At the MAC, each connection belongs to a
single service class and is associated with a set of
QoS parameters that quantify its characteristics.
Four QoS classes are provided by the MAC in the
IEEE 802.16 standard.
1) Unsolicited grant service (UGS) supports
constant bit rate (CBR) or fixed throughput
connections such as E1/T1 lines and voice over IP
(VoIP). This service provides guarantees on
throughput, latency, and jitter to the necessary
levels as TDM services. The QoS metrics here are
the packet error rate (PER) and the service rate.
2) Real-time polling service (rtPS) provides
guarantees on throughput and latency, but with
greater tolerance on latency relative to UGS, e.g.,
MPEG video conferencing and video streaming.
The delayed packets are useless and will be
dropped. The QoS metrics are the PER and the
maximum delay (or the maximum delay for a given
outage probability).
Pagadala venkata subba reddy and prof.Y.V Bhaskara
3) Nonreal-time polling service (nrtPS) provides
guarantees in terms of throughput only and is
therefore suitable for mission critical data
applications, such as File Transfer Protocol (FTP).
These applications are time-insensitive and require
minimum throughput. For example, an FTP file can
be downloaded within a bounded waiting time if the
minimum reserved rate is guaranteed. The QoS
metrics are the PER and the minimum reserved rate.
D. AMC DESIGN AT THE PHY
Efficient bandwidth utilization for a
prescribed PER performance at the PHY can be
accomplished with AMC schemes, which match
transmission parameters to the time-varying
wireless channel conditions adaptively and have
been adopted by many standard wireless networks,
such as IEEE 802.11/15/16 and 3GPP/3GPP2. Each
connection with rtPS, nrtPS, and BE services relies
on AMC at the PHY. The objective of AMC is to
maximize the data rate by adjusting transmission
modes to channel variations while maintaining a
prescribed PER P0, and the design procedure is
similar to that proposed.
Let N denote the total number of transmission
modes available (N = 6 for TM). As in we assume
constant power transmission and partition the entire
signal-to-noise ratio (SNR) range in N + 1
nonoverlapping consecutive intervals, with
boundary points denoted as { n}N+1 n=0 . In this
case mode n is chosen when ∈ [ n, n+1), for n =
1, . . . , N.
E. ROUTER STRUCTURE
Every node has a fixed number of
transmitter-receiver pairs (transceivers) used to set
up communication links with other nodes. The
number of transceivers that are in an IDLE state,
varies dynamically with time depending on the
traffic load and the average session duration. A
necessary condition for a new connection to be
established is that at least one transceiver is
available at every node in the path to the
destination. New connection requests are blocked
when one or more nodes along the path do not have
any of their transceivers idle. A pure first-come
first-serve policy is assumed without considering
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International Journal of Engineering Science Invention Research & Development; Vol. IV, Issue II, AUGUST 2017
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any preemptive policies in which a high priority
session can preempt an ongoing session of lower
priority. For simplicity no priority is given to handoff requests which have to compete against new
connection requests in search of communication
paths.
F. ALGORITHM EXECUTION
Algorithm execution can be viewed as
occurring in three logical phases, the “Construction
phase”, the “Maintenance phase” and the
“Termination
Phase”,
which
execute
simultaneously in a dynamic topology. A source
node which desires a connection to the DEST
transmits a “Connection-Request” (CR) packet
along one of the existing DN links. If multiple DN
links exist a decision over which link to transmit is
made either upon information on the resources
available along the existing paths or randomly, if no
such information has been obtained. In particular
the parameter for the selection of the DN link is the
available number of transceivers along the outgoing
paths and such information is collected during the
algorithm construction phase by messages
piggybacked in the transmitted acknowledgments.
“Acknowledgment” (ACK) control message (node
DEST in the example of figure 1(d)). Otherwise if
the request cannot be serviced by the DEST , a
NAK is transmitted back to the link over which the
CR was received. ACK messages are generated and
transmitted by destination nodes, are destined to the
source node of the CR and must follow the same
path of the CR in the reverse direction.
IV. NETWORK SIMULATOR
A network simulator is a software
program that imitates the working of a computer
network. In simulators, the computer network is
typically modeled with devices, traffic etc and the
performance is analyzed. Typically, users can then
customize the simulator to fulfill their specific
analysis needs. Simulators typically come with
support for the most popular protocols in the use
today, such as Wireless LAN, Wi-Max, UDP, and
TCP. A network simulator is a piece of software or
hardware that predicts the behaviour of a network,
without an actual network being present. NS is an
object oriented simulator, written in C++, with an
OTcl interpreter as a frontend.
Figure 4. Cooperation of C++ and Otcl language
Figure 3. Example of algorithm execution
If a CR reaches the DEST and the request is
admitted, the destination node updates the
corresponding entry in its connectivity table and
transmits backwards to the source an
Pagadala venkata subba reddy and prof.Y.V Bhaskara
The simulator supports a class hierarchy
in C++ and a similar class hierarchy within the
OTcl interpreter. The two hierarchies are closely
related to each other; from the user‟s perspective,
there is one-to-one correspondence between a class
in the interpreted hierarchy and one in the compiled
hierarchy. The root of this hierarchy is the class Tcl
object. Users create a new simulator objects
through the interpreter; these objects are
instantiated within the hierarchy. The interpreted
class hierarchy is automatically established through
methods defined in the class Tcl object. There are
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International Journal of Engineering Science Invention Research & Development; Vol. IV, Issue II, AUGUST 2017
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other hierarchies in the C++ code and OTcl scripts;
these other hierarchies are not mirrored in the
manner of Tcl object.
A. NETWORK SIMULATOR 2 (NS2)
NS2 is an open- source simulation tool
that runs on Linux. It is a discreet event simulator
targeted at networking research and provides
substantial support for simulation of routing,
multicast protocols and IP protocols, such as UDP,
TCP over wired and wireless (local and satellite)
networks. It has many advantages that make it
useful tool, such as support for multiple protocols
and the capability of graphically detailing network
traffic. Additionally, NS2 supports several
algorithms in routing and queuing. Queuing
algorithms include fair queuing, deficit round-robin
and FIFO. REAL is a network simulator originally
intended for studying the dynamic behavior of flow
and congestion control schemes in packet switched
data network. NS2 is available on several platforms
such as FreeBSD, Linux, Sim OS and Solaris. NS2
also builds and runs under Windows.
C. NODE METHODS: CONFIGURING THE
NODE
Procedures to configure an individual node can be
classified into:
1. Control functions
2. Address and Port number management, unicast
routing functions
3. Agent management
4. Adding neighbours.
V. SIMULATION RESULTS
Figure 6. Communicate Different Types of Cluster Head
Figure 5.Simplified user’s view of NS
B. NODE BASICS
The basic primitive for creating a node is
set ns[new Simulator]
$ns node
The instance procedure node constructs a node out
of simpler classifier objects. All nodes contain the
following components:
1. An address or id_, monotonically increasing by 1
(from initial value o) across the simulation
namespace as nodes are created
2. A list of neighbors (neighbor_)
3. A list of agents (agent_)
4. A node type identifier (node type_)
Pagadala venkata subba reddy and prof.Y.V Bhaskara
To calculate the SEP of the scheduled
user, we require the cumulative distribution
function (CDF) of the end-to-end SNR. As the CDF
is dependent on the state vector s, we first calculate
the conditional CDF. The expression for the
conditional CDF of the SNR of the relay-user link
of the scheduled user k∗ is given in Lemma 2. To
simplify the notation, we write γ2 = γRk∗ for the
SNR of the scheduled user’s relay-to-user link.
Figure 7 Comparison between and proposed and existing system in
Energy value
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the wireless bandwidth efficiently by exploiting
multiuser diversity among connections with
different kinds of services. Furthermore, our
scheduler enjoys flexibility, scalability, and low
execution difficulty. Performance of our scheduler
was evaluated via simulations in the IEEE 802.16
standard setting, where the upper-bound rtPS,
nrtPS, BE, and the delay guard time ΔTi were set
heuristically.
VII. REFERENCES
Figure 8 Comparison between and proposed and existing system in
PDR
Figure 9 Comparison between and proposed and existing system in
Throughput
VI. CONCLUSION AND FUTURE DIRECTIONS
Developed a cross-layer scheduling
algorithm at the MAC layer for multiple
connections with different QoS needs, which can be
used in mobile networks, mobile ad hoc networks,
and wireless sensor networks. Each connection
admitted in the system is assigned a priority, which
is updated dynamically depending on its channel
quality, QoS satisfaction, and service priority; thus,
the connection with the highest priority is scheduled
first each time. Our proposed scheduler offers
prescribed delay, and rate guarantees for rea ltime
and non real-time traffic; at the same time, it uses
Pagadala venkata subba reddy and prof.Y.V Bhaskara
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