Comparative analysis of 802.11b&g WLAN systems based on Throughput metric

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 09 Issue: 11 | Nov 2022 www.irjet.net p-ISSN: 2395-0072
© 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 886
Comparative analysis of 802.11b&g WLAN systems based on
Throughput metric
Umar Usman Bello1, Bello Usman2, Aliyu Uthman Bello3
1Engineer, Directorate of Information and Communication Technology, ATBU Bauchi, Nigeria
2Lecturer, Department of Computer Science, FCT-College of Education, Zuba, Abuja, Nigeria.
3Lecturer, Department of Information Technology, Federal University Dutse, Nigeria
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Abstract - This paper Examines the maximum data
throughput performance of a wireless network 802.11b&g
Using iperf for sending UDP datastreamsacrosseachnetwork
thereby computing the experimental and theoretical
parameters such as Throughput values, data loss and round
trip time. The results were displayed in Graphical formats for
comparative analysis which showed that theoretical
throughput is higher than the experimental throughput in
both 802.11 b&g. And that 802.11g has comparatively greater
throughput metric than 802.11b
Key Words: Throughput, payload, 802.11, WLAN,
1. INTRODUCTION
Wireless networking is considered to be an accepted
complementary to the Ethernet wired Networking [1]. It
involves wireless equipment fortransmissionofdata andfor
effective communication. Its importance led to the fact that
most current mobile and portable devices are currently
empowered with wireless fidelity(Wi-Fi) capabilities ,
allowing end users to connect to access points in proximity
for internet access or to setup Ad-hoc Networks for file
sharing etc due to its low cost , easy setup and
deployment.[2]
Wireless Networks are made by configuring Wirelessaccess
points. There 802.11 x standards which guide the
description of Wi-Fi and are 802.11a,802.111b,802.11g and
802.11n. 802.11a has a typical data rateof25Mbpsandreach
54Mbps with 100 as indoor range with operating frequency
of 5GHz. 802.11 b has a typical data rate of 6.5Mbps that can
extends to 11Mbsps with the same 100 feet of indoor range
but with 2.4GHz operating frequency.802.11g, on the other
hand, has a data rate of 25Mbps, peak rate of 54Mbps and
indoor range of 100 feet having operating frequency of
2.4GHz. Note that 802.11b&g are mostly compatible with
most wireless/router cards referred these standard as b/g
or 802.11b/g. Furthermore, 802.11n has a typical data rate
of 200Mbps that extends to 540Mbps with 160 feet indoor
range operating at either 2.4GHz or 5GHz. Finally, Overhead
has been described as the fundamental problem of Medium
Access Control (MAC) inefficiency [3]
As more and more daily activities are carried out via
Internet-based services and systems, modern civilization is
becoming increasingly reliant on powerful and efficient
communicationnetworks.[3].TheIEEEproducedthe802.11
series of specifications for wirelessLAN technology.In1997,
IEEE approved the 802.11 specification. Due to the ease of
installation and the growing popularityoflaptopcomputers,
wireless local area networks (WLAN) have become popular
in the home. WLAN stands for Wireless Fidelity and is based
on the IEEE 802.11 standard. The 802.11 working group's
tasks have only generated a few extensions to the original
specifications. These extensions' products are named by the
task group and the original standard;for example,802.11bis
a task group b extension. 802.11b, 802.11a, 802.11g, and
802.11n are the most widely used 802.11 extensions [5]
IEEE 802.11b is an 802.11 extension that uses just DSSS and
can transmit up to 11 Mbps (with a fall back of 5.5, 2, and 1
Mbps) in the 2.4GHz range. IEEE 802.11b is also known as
wireless fidelity (WiFi) or 802.11 high rate.). The 802.11g
standard uses the 2.4GHz band and can deliver speeds of up
to 54 Mbps (with a fall back to 48, 36, 24, 18, 11, 5.5, 2, and 1
Mbps). The 802.11g varies from the 802.11b in that it can
employ OFDM (the 802.11g draft demands the use of OFDM
for rates greater than 20 Mbps). [4]
The IEEE 802.11 family is the most widely used standard
that has numerous extensions while others are underway.
IEEE 802.11 standards, which were first presented in 1999,
were largely developed with the home and office context in
mind for wireless local area connectivity. With the
implementation of IEEE 802.11b [2], the maximumdata rate
per AP rose from 2Mbps to 11Mbps. Newer IEEE 802.11g
and IEEE 802.11a extensions provided a maximumdata rate
of 54Mbps per AP using a variety of approaches to raise the
maximum data rates [3-5]. Currently, WLAN equipment
based on IEEE 802.11g support data rates of 100-125 Mbps
[6]
Network steganography is now recognized as a new danger
to network security that can be utilized for a variety of
purposes, including data exfiltration and network attacks.
The IEEE 802.11 standardsdidnotregardwirelesslocal area
networks (WLANs) as a serious area for data concealing,
owing to their restricted range (the rangefor802.11a/b/gis
30m indoors and 100m outdoors)., the range of 802.11n is
increased). IEEE 802.11 was, nevertheless, used to
communicate secret data among Russian agents

apprehended in the United States in June 2010 [1]. WLAN is
also one of the various means of communication among
soldiers on the battlefield from a military standpoint. [7]
802.11b
In July 1999, IEEE added the 802.11b specification to the
original 802.11 standard. 802.11b allows for a bandwidth of
up to 2.4 GHz.11 Mbps, comparable to traditional Ethernet.
The original 802.11 standard uses the same uncontrolled
radio signaling frequency (2.4 GHz) as 802.11b. Vendors
frequently want to use these frequencies in order to reduce
their production costs. Because 802.11b equipment is
unregulated, it may cause interference with microwave
ovens, cordless phones, and other 2.4 GHz-based gadgets.
However, by placing 802.11b equipment at a safe distance
from other machines, interference can easily be evaded. [8]
802.11g
WLAN solutions supporting a newer standard known as
802.11g first appeared on the market in 2002 and 2003.
802.11g tries to integrate the greatest features of 802.11a
and 802.11b. 802.11g provides up to 54 Mbps of bandwidth
and uses the 2.4 GHz frequency for increased range.
Backward compatibility between 802.11g and 802.11b
means that 802.11g access points will functionwith802.11b
wireless network adapters and vice versa. [9]
2.0 THEORITICAL THROUGHPUT DEVELOPMENT
2.1 PREAMBLE
Throughput of a Communication protocol can be defined as
the number of informationbitstransmittedpertransmission
cycle (in bps).
Hence it can mathematically be simplified as;
Throughput (Mb/s) = Amount of data (bits) (1)
Transmission Time (μS)
The iperf tool sends UDP data packets of 1470bytes
(application data) by default.
Carrier Sense Multiple Access /Collision Avoidance
(CSMA/CD) isa schemedefinedbyDistributionCoordination
Function (DCF) where each mobile node has a fair chance to
access the wireless medium in 802.11MAC. Short Inter-
Frame Spacing (SIFS) is used in 802.11 to transmit high
priority frames just like Request-to-Send (RTS) , Clear-To-
Send (CTS) as well as Acknowledgement(ACK)[8]
Distributed coordinator Function Inter Frame Space (DIFS)
this normally differentiates between twotransmissions.The
time associated with DIFS is given according to (Michele-
Segata et al, 2009) as;
TDIFS = TSIFS + 2 + TSLOT= 10μS + 2 * 20Μs = 50μS. (2)
Slot time is Contention Window (CW) size is defined as the
multiple of time slot and plays major role during back-off
Procedure which has to be executed by each mobile node
before transmission [9]
Transmission Control protocol (TCP) is an Example of
responsive protocol providing responsive traffic while User
datagram Protocol (UDP) is an Example of non-responsive
protocol providing non-responsive Traffic [10]
More than 9.5 billion devices, which are IEEE 802.11
compliant are pervasive with United States alone having
about fifty million Wi-Fi networks extensive IEEE 802.11
infrastructure devices. Internet of Things (IoT) challenges
can be addressed by IEEE802.11 even though it comes with
high consumption of power such that it has to powered via
batteries or harvesting the power which was later solved
through the introduction of power saving mode(PSM) that’s
hibernate the radio most of the time with the purpose of
energy reduction. In order not to lose frames during
hibernation period, the access point (AP) in the network
stores those frames that were directed to the sleeping
station (STA) which can be utilized during wake up process.
[11]
Marcov chain is a mathematical model which is one of the
most popular techniques that analyses the performance of
IEEE802.11 Distributed Coordination Factor (DCF). Markov
chain is normally classified in to three dimension as 1-
Dimension, 2-dimension and 3-dimension that summarizes
their characteristics. The idea is to choose the appropriate
dimension in relation to complexity of the desired MAC
protocol with respect to communication scenarios.Wireless
LAN and Media and Access layers normallygettheirdetailed
specification from IEEE 802.11 Standard which directs the
scheduling processes efficiently via two techniques named;
DCF and PCF (point coordination factor.)[12]
The first release of IEEE 802.11 Standard was in June 1997
by the IEEE/MAN committee and subsequently upgraded to
draw near the advancesincommunicationtechnologies. The
protocols started by 11a, 11b , 11g then upgraded 11n
before coming up with11ac.11nprovidesimprovedfeatures
over the a, b & c while 11ac is better than 11n [13]
The IEEE802.11b, otherwise known as High rate (Wi-Fi),
offers 11Mbps transmissions in the 2.4GHz band.
Throughput is the average rateofvictoriousmessagerelease
over a channel of communication. In 1999 approval release
of the IEEE802.11b standard facilitated the frame
fragmentation which is the procedure that allows 802.11
frames to be partitioned into lesser fragments to spread
individually to the target destination where the frame
reassembly takes place at the MAC layer. [14]
Transmission control protocol (TCP) accounts for over 80%
of whole internet traffic. To understand the WLAN systems
capability to utilize TCP in accessing the internet, it quite

necessary to forecast TCPs throughput. (Aziz, O.A., etal
2020). Maximum throughput can be passed across a
passageway which is known as bandwidth capacity,
Available bandwidth is the amount of unused capacityatthe
same passageway. [15]
Even though it is not new technology per say, IEE802.11b
WLAN system remains the top commonly used technology
that equally offers the widest range in the wireless
equipment deployment. Where IEEE802.11b is used in a
network alongside other technologies, especially when the
covered distance is favored over high throughput or
bandwidth, IEEE802.11b is normally preferred over newer
technologies because they are forced to make use of lower
data speeds. [16]
2.2 COMPUTING THE THEORITICAL LIMITS
For 802.11b
The maximum throughput can be achieved under best case
scenario by setting up an error free channel which is ideal
for experimentation. There has to be only one active station
for sending and accepting packets to another station which
must acknowledge receipt. It also worth noting that
maximum throughput should be higher than an ordinary
throughput whereas Minimum delay should be lower than
an ordinary delay.
MT = 8LDATA
TD_DATA+TD_ACK +2τ + TDIFS +TSIFS+CW (3)
Maximum delay in equation (3) is a function of payload size
in bytes multiplied by eight, the result of which to be all be
divided by a summation of transmissiontimeforthe payload
( TD_DATA), acknowledgement transmission time (TD_ACK),
twice the propagation delay (2τ) and SIFStime(TSIFS)aswell
as contention window (CW).
TD_DATA = TP + TPHY + 8LH_DATA + 8LDATA (4)
100000RDATA
Transmission time for the payload (TD_DATA) in (3) can
further be highlighted as a summation of transmission time
of physical preamble (TP) added to the transmission time of
the PHY header (TPHY) which is then summed along with the
MAC overhead in bytes (LH_DATA ) plus payload size in bytes
(LDATA) and the summation to be divided by data rate(RDATA)
resulting to the formation of equation (4).
The other aspect of maximum throughput (MT) equation is
the Acknowledgement transmission time (TD_ACK) in (4)
which is the result of the acknowledgement size in bytes
(LACK) by the 100,000th value of control rate (RACK) to be
added with the summation of TP andTPHY.Thisishow(5) was
formed.
TD_ACK = TP + TPHY + 8LACK (5)
100000RACK
The generalized formula can be simplified as shown below;
T = 8Psize (6)
756 + 8 * (42 +Psize)
11
From the above we can form the table for payload against
Throughput
For 802.11g
The following notations were used:
T: Throughput, Psize: Payload size, DIFS: Distributed
coordinator Function Inter Frame Space,PHY:Physical layer
header, FCS: Fluorescence Correlation Spectroscopy, TAIL:
Tail bits, PAD: Pad bits, ACK: Acknowledgement and MAC:
Medium Access Control.
The throughput is given from the generalized formula given
in equation (7) below, which presents throughput as the
function of Payload size in respect of the summation of
parameters including: TDIFS, TBACKOFF, TPHY, TSERVICE, TFCS, TTAIL,
TPAD, TACK and TMAC.
T = Psize (7)
TDIFF+TBACKOFF+TPHY +TSERVICE
+ TFCS+TTAIL+ TPAD+TACK +TMAC
Substituting for the theoretical values from the paper and
varying my packet size values from my experiment leads to
(8);
NOTE
(TDIFF=28μS, TBACKOFF=138.5μS, TPHY =20μS, Tservice=0.3μS,
TFCS=0.59μS TTAIL=0.11μS, TPAD=0.33μS, TACK = 30μS, TMAC=
3.56μS)
T = Psize (8)
28μS+138.5μS+20μS+0.3μS+0.59μS
+0.11μS+0.33μS+30μS+3.56μS
The formula can further be generalized as shown in (9)
below;
T = 8PSIZE (9)
231.39 + 8PSIZE
54

3.0 METHODOLOGY
3.1 EXPERIMENTAL EQUIPMENT
3.11: HARDAWRE
2No. Computer Laptop: The Computer laptop with a
running Windows Operating System (OS) was used. It was a
HP Elite book E50 G2, 2.60GB processor and 64-bit
Operating system. We also used another laptop to run the
iperf generation software tool.Itwasa MacBook Pro,Intel i5,
4G RAM, IOS.
1No. Access Point: (Linksys WRT10N Wirelessrouter):The
Access point (AP) was used for connecting the two laptops
(server and client).
3.12 SOFTWARE
Iperf traffic generation software:
Iperf3 is a tool for actively measuring the maximum
bandwidth achievable on IP networks. It allows you to fine-
tune a variety of timing, buffer, and protocol options (TCP,
UDP, SCTP with IPv4 and IPv6). It reports the bandwidth,
loss, and other parameters for each test. This is a brand-new
implementation with no code in common with the original
iPerf, and it is also not backwards compatible.
Spectrum Analyzer (Chanalyser 4):
Chanalyser 4 is a software program by MetaGeek thatgather
data from two sources. The wireless adapter from a
computer and the spectrum analysis from the Wi-Spy work
together in order to give comprehensive look atourwireless
environment.
3.2 EXPERIMENTAL METHODS
The experiment was carried out using two laptops and
Linksys WRT10N Access Point set at a frequency of 2.4GHz
at channel 6. A laptop was used as server using DHCP server
for automatically assigning IP address to the Laptops in
connection to the Access Point while the other laptop serves
as client. We thereby sent out data using iperf traffic
generating software which was run onbothlaptopsand also
used chanalyser 4 Spectrum Analyser for monitoring the
behaviour of the Network.
Data Packets were sent by running iperf on the two laptops
to collect the data for the selected speed. Any packet sent on
the iperf based client Laptop will be monitored on the
server’s laptop running the same iperf while the output
results of the seven (7) tested payloads were recorded for
analysis. The seven payloads tested in the experiment were
100, 250, 500, 750, 1000, 1250 and 1400 respectively
measured in bytes. And the summarisedthroughputsresults
are accordingly noted in the table formats for plotting unto
graphs.
4.1 RESULTS
The results obtained from our experimental and theoretical
work.
Throughput analysis of 802.11b and 802.11g standards is
hereby presented in graphs shown hereunder with
supplementary snapshots of the outputs generated by the
spectrum analyser. The vertical and horizontal axis of the
graphs represents throughput in bits per seconds and
Payloads in bytes respectively. Discussion on the results is
described in the Next section of this technical paper.
Table 1: 802.11 b Throughput against Payload
Payload
(Bytes)
Theoretical
Throughput
Experimental
Throughput
Differential
100 0.93 0.45 0.48
250 2.07 1.48 0.59
500 3.48 2.48 1.0
750 4.51 3.26 1.25
1000 5.28 3.95 1.33
1250 5.90 4.26 1.64
1400 6.21 4.57 1.64
Figure1a: 802.11 b Throughput against Payload

Figure 1b: Chanalyser output for 802.11 b
Table 2: 802.11g Throughput against Payload
Payload
(Bytes)
Theoretical
Throughput
Experimental
Throughput
Differential
100 2.28 3.35 -1.07
250 7.45 6.95 0.5
500 13.10 9.79 3.13
750 17.51 13.00 4.51
1000 21.08 15.07 6.01
1250 24.01 20.96 3.05
1400 25.52 23.14 2.38
Figure 2a: 802.11 g Throughput against Payload.
Figure 2b: Chanalyser output for 802.11 g
Table 3: 802.11b & g Throughput against Payload
Payload
(bytes)
Theoretical
Throughput
– b
Experimental
Throughput -
b
Theoretical
Throughput
- g
Experimental
Throughput -
g
100 0.93 0.45 2.28 3.35
250 2.07 1.48 7.45 6.95
500 3.48 2.48 13.10 9.79
750 4.51 3.26 17.51 13.00
1000 5.28 3.95 21.08 15.07
1250 5.90 4.26 24.01 20.96
1400 6.21 4.57 25.52 23.14
Figure 3: 802.11 b&g Throughput against Payload.

4.2. DISCUSSION OF RESULTS
After plotting the throughput graphs for both the two
standards that are 802.11b and 802.11g, I observed that in
the case of 802.11b there exist fairly thesamepatternfor the
theoretical and experimental throughput especiallyatlower
payloads as seen in figure1a. For the 802.11g, both the
theoretical and experimental throughput exhibited similar
manner but the experimental throughput at 100bytes is
higher causing an overlap where there is sudden drop of the
experimental value slightly at 1000bytes of payload due to
possible interference from the surroundingwirelessdevices
as depicted in table 2. Generally 802.11g has higher
throughput performancein boththeatrical andexperimental
values compared to 802.11b as shown in Table 3 just as
802.11g traffic is also greater than 802.11b as captured by
chanalyser in Figure1b and Figure 2b respectively.
While table 1 showed the comparative values of both
theoretical and experimental throughput associated with
802.11b, Table2 showed the comparative values of both
theoretical and experimental values of 802.11g. Figure 1a
showed how theoretical throughput is higher than the
experimental throughputin 802.11b whereasin802.11g, the
experimental throughput appeared higher in much lower
payload but as soon as the payload started increasing, the
experimental throughput maintained the dominance over
the experimental throughput as in Figure 2a. The broader
pictured was shown in Figure 3 that depicted the general
overview, comparing both the 802.11b and 802.11g such
that the 802.11g was pictorially shown to be much higher
than the 802.11b in both theoretical and experimental
scenarios.
5.0 CONCLUSION
The paper presents the calculation of Maximum data
Throughput by considering both the theoretical and
experimental values of 802.11b and 802.11g Networks
thereby graphically showing how802.11gstandardishigher
than 802.11b in terms varying payloads. Effects of
interference have been considered and all timing and
frequency settings for calculating the throughput were
accordingly implemented.

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