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Software Defined Radio Implementation (With simulation & analysis)

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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

Software Defined Radio Implementation

(With simulation & analysis)
Shriram K Vasudevan Sivaraman R Z.C.Alex
Assistant Professor II Year M.Tech S.S.T, Senior Professor and Director,
VIT University, VIT University, SENSE
Vellore, INDIA. Vellore, INDIA. VIT University, Vellore, INDIA.

ABSTRACT To develop a suitable channel model to include signal

Software Defined Radio is an all new technology being fading and Additive White Gaussian Noise.
developed in the 21st century. Over a past couple of decades To develop necessary equations for calculation of
many Mobile communication standards have evolved and even BER curves for the type of modulation and coding
today researches are going to develop new standards. Different schemes used.
standards of Mobile communication use different type of
hardware circuitry. The existing mobile communication Index Terms
standards are primarily regional and not global. So efforts are SDR, Simulink, Matlab, Bluetooth
going on to develop systems which can support multiple mobile
communication standards using same hardware but swapping 1. INTRODUCTION
the software. Software Defined Radio is a radio communications transceiver
The main aim of this paper is to develop a model of a Software system in which all the typical components of a communication
defined Radio using SIMULINK tool to implement the IEEE system such as mixers, modulators/demodulators, detectors,
802.11 standard and the Bluetooth standard. The main aim of amplifiers are implemented through software rather than
this paper is to build various protocols for WLAN and the hardware.
Bluetooth standards and to demonstrate their functionality. This This approach is helpful because there is a scope of developing
includes implementation of IEEE 802.11a standard for the a system which is compatible with more than one mobile
WLAN and basic core protocols for the Bluetooth. According to communication standard. This can be achieved by using re-
the IEEE 802.11a standard out of the various transmission configurable hardware and swapping the software for different
modes the basic transmission mode (BPSK with 6Mbps technologies.
transmission speed) was implemented. For forward error
correction half convolution codes are used. The communication
channel is assumed to be flat fading channel where the 1.1 History of software defined radio
transmitted sub carrier undergoes flat fading. The ideal channel evolution.
model for this type of channel is chosen as Nakagami channel. The initial developments of software defined radio took place
Regarding the Bluetooth technology all the core protocols of during 1970’s. During that phase VLF radios which are based
Bluetooth are implemented and the type of modulation is on ADC connected to an 8085 microprocessor are used by the
Gaussian phase shift keying and frequency hopping spread ground forces of USA and Great Britain.
spectrum. The first major push for the development of the SDRs is made
through US military paper named SpeakEasy. The primary goal
Objectives and goals of our paper are stated as follows: of the SpeakEasy paper was to use programmable processing to
To develop a model of a Software Defined Radio emulate more than 10 existing military radios, operating in
which supports the IEEE 802.11a standard and frequency bands between 2 and 2000MHz. Further, another
Bluetooth standard using the SIMULINK tool? design goal was to be able to easily incorporate new coding and
To implement all the main protocol stacks for WLAN modulation standards in the future, so that military
and Bluetooth Protocols and verify their functionality. communications can keep pace with advances in coding and
To transmit the data as frames using the format modulation techniques. This paper went on in two phases.
specified for the standard, to compress the binary data
using source coding algorithm and also encode the 1.2 Speakeasy phase I
data for Forward Error Correction (FEC). From 1992 to 1995, the goal was to produce a radio for the U.S.
To modulate the binary stream of data using the Army that could operate from 2 MHz to 2 GHz, and operate
BPSK modulation for WLAN mode which supports with ground force radios (frequency-agile VHF, FM, and
the basic transfer mode with 6 Mbps speed. SINCGARS), Air Force radios (VHF AM), Naval Radios (VHF
For the Bluetooth standard the basic modulation AM and HF SSB teleprinters) and satellites (microwave QAM).
scheme used is GPSK and Frequency hopping spread Some particular goals were to provide a new signal format in
spectrum is used. two weeks from a standing start, and demonstrate a radio into
To implement WEP algorithm for WLAN security which multiple contractors could plug parts and software.
and also CRC-16 for protecting the integrity of the The paper was demonstrated at TF-XXI Advanced War fighting
data. Exercise, and met all these goals. There was some discontent
To implement point to point communication and data with certain unspecified features. Its cryptographic processor
transfer for the Bluetooth standard. could not change context fast enough to keep several radio
To implement CSMA/CA technique and also conversations on the air at once. Its software architecture,
implement different basic functions such as packet though practical enough, bore no resemblance to any other.
routing, Authentication, Request to transmit etc. for The basic arrangement of the radio receiver used an antenna
the WLAN standard. feeding an amplifier and down-converter feeding an automatic
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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

gain control, which fed an analog to digital converter that was research with its Reconfiguration Management Architecture as
on a computer VME bus with a lot of digital signal processors. well as many on-going papers in the industry.
The transmitter had digital to analog converters on the PCI bus Despite such a wide range of activities, and due to the
feeding an up converter (mixer) that led to a power amplifier complexity of the problem area there is still a wide area of
and antenna. The very wide frequency range was divided into a uncharted territory for fundamental research into re-
few sub-bands with different analog radio technologies feeding configurability and the various levels of SDR technology.
the same analog to digital converters. This has since become a Successful development of SDR equipments will still require a
standard design scheme for wide band software radios. huge amount of efforts in the next 5–10 years.

1.3 SpeakEasy Phase II 1.4 Factors to be considered for installation

The goal was to get a more quickly reconfigurable architecture of WLAN
(i.e. several conversations at once), in open software One of the first considerations facing the enterprise that wants
architecture, with cross channel connectivity (the radio can to deploy wireless networking is – which wireless technologies
bridge different radio protocols). The secondary goals were to to adopt and when? This part examines the three prevalent
make it smaller, weigh less and cheaper. standards, 802.11b, 802.11g, and 802.11a and chooses an
The paper produced a demonstration radio only fifteen months appropriate standard. We should also look at two wireless LAN
into a three-year research paper. The demonstration was so (WLAN) architectures – standalone access points and centrally
successful that further development was halted, and the radio controlled coordinated access points – and choose
went into production with only a 4 MHz to 400 MHz range. implementation considerations that can help to decide which
The software architecture identified standard interfaces for type of architectures to adopt in a particular environment.
different modules of the radio: "radio frequency control" to To help decide which standards-based products to implement a
manage the analog parts of the radio, "modem control" managed site survey should be performed that identifies the most
resources for modulation and demodulation schemes (FM, AM, appropriate wireless technologies and architectures for your
SSB, QAM, etc), "waveform processing" modules actually environment.
performed the modem functions, "key processing" and
"cryptographic processing" managed the cryptographic 1.5 Site survey
functions, a "multimedia" module did voice processing, a The success of a wireless LAN deployment depends on the site
"human interface" provided local or remote controls, there was survey, before organizing the WLAN it is necessary to
a "routing" module for network services, and a "control" understand the needs of the users in the current environment.
module to keep it all straight. The main aim is to identify appropriate technology to apply,
The modules are said to communicate without a central obstacles to avoid or eliminate or work around, coverage
operating system. Instead, they send messages over the PCI patterns to adopt and amount of capacity needed. The site
computer bus to each other with a layered protocol. survey should yield a network design document that describes
As a military paper, the radio strongly distinguished "red" the location of each access point, its coverage area, and the
(unsecured secret data) and "black" (cryptographically-secured 802.11 a, b, or g channel selections for the access point. The
data). network design document should also provide a complete Bill
Developed primarily for the military applications the Software of Materials, indicating the WLAN equipment and supplies,
Defined Radio moved on to civil and commercial applications. infrastructure equipment and supplies to provide Power over
A Non-Profit organization called SDR Forum which was Ethernet (PoE) and additional switch ports.
previously known as Modular Multifunction Information
Transfer System Forum was founded with the aim to develop a
set of technical specifications and to define the requirements 1.6 User’s survey
and eventually standards for the realisation of SDRs. Moving It describes about the needs, expectations & applications of the
from the initial military background, all branches of the wireless user. Also deals with traffic types, volumes and their presence.
industry ranging from defence, commercial wireless, civil User’s locations and their distance from the access points.
government to regulatory bodies and academia are represented
in this forum. The activities of the SDR Forum have helped 1.7 Work space
raising the awareness of this emerging technology and are It defines the space and usage of WLAN services , also it tells
influencing the regulatory framework for reconfigurable SDR about the work area, room and hallways supported by the
Terminals. wireless infrastructure.
Other research efforts, namely those of the European
Commission, provide significant advances in hardware and
software technologies, the research frameworks ACTS 1.8 Obstacles to signal strength
(Advanced Communications Technologies and Services) and In general, objects absorb or reflect signal strength and degrade
ESPRIT (the EU information technologies programme) initiated or block the signal. Indentifying the obstacles are of utmost
papers including FIRST (Flexible Integrated Radio Systems importance and those obstacles are walls, furniture, ceiling tiles,
Technology), SORT (Software Radio Technology), and SLATS natural elements (tree, bush, water), coated glass.
(Software Libraries for Advanced Terminal Solutions). While
the current fifth framework papers include TRUST 1.9 Security considerations
(Transparently Reconfigurable Ubiquitous Terminal), CAST The inherently open nature of wireless access – compared to the
(Configurable radio with Advanced Software Technology), wired world – creates significant security concerns; chief among
MOBIVAS (downloadable Mobile Value Added Services them is user authentication and rights enforcement, and data
through software radio and switching integrated platforms), encryption. Broadcast signals often travel into public areas that
SODERA (reconfigurable radio for Software Defined Radio for can be accessed by "eavesdropping" individuals who have not
third generation mobile terminals), and PASTORAL (Platform passed through any type of authentication process to validate
And Software for Terminals Operationally Reconfigurable). their presence at the site. The site survey should identify the
Other initiatives include UKs Mobile VCEs Soft-Terminal

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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

security status of all the locations considered for wireless

access.
The security solution must control network access in different
ways for different types of users who may be in the same
location. Some users, such as employees, may be entitled to
total or broad access. Other users, such as guests or contractors,
may be entitled only to more limited access. In a more
sophisticated solution, an access controller sits between the
access point and the network, functioning as a gatekeeper, or
rights administrator, at the network edge. With such a device,
for example, employees can be granted access to corporate
resources, and guests may be granted only access to the Internet. Fig 2 Centrally coordinated wireless networks
The site assessment should note where guests, contractors, or
other non–employee users may be located, so that appropriate 2. IMPLIMENTATION CONSIDERATIONS
security solutions can be created for those areas. Both the standalone and centrally coordinated architectures
have advantages and disadvantages, depending on the age of the
1.20 Signal noise wired infrastructure, deployment area, building architecture, and
Noise from cordless phones, wireless headsets, and other non- types of applications that you want to support. Regardless which
protocol devices can interfere with an access point trying to approach you choose, it is essential that your architecture
send or receive data. The site survey should identify the sources provide you with a way to manage your network efficiently and
of signal noise present in each deployment area so that the effectively.
WLAN can avoid at least the already existing noise sources. A standalone access point WLAN is particularly well suited in
environments where:
1.21 Stand alone and centrally coordinated There is a smaller isolated wireless coverage area that
requires only one or a few access points
wireless networks There is a need for wireless bridging from a main site
In planning a wireless network, one needs to determine which building to a branch office or to a remote portable or
WLAN architectures to adopt in a particular environment. Both temporary building such as a portable classroom.
architectures standalone access points and centrally coordinated However, the operational overhead to manage and maintain a
have benefits that are well suited to different environments. wireless LAN increases with the size of the wireless LAN
A wireless network, based on standalone access points, relies on deployment. Wireless LAN management tools help simplify
the integrated functionality of each access point to enable configuration and monitoring of the LAN, but the inherent
wireless services, authentication and security. “independence” of these access points presents a challenge in
addressing security, configuration control, bandwidth
predictability and reliability , As users and applications become
dependent on an always available and reliable wireless LAN
connection.
A centrally coordinated WLAN is well suited deploy where.
There are one or more large wireless coverage areas
that require multiple radio ports possibly accompanied
by several smaller isolated coverage areas.
RF network self-healing is required.
A redundant stateful-failover situation is required.

3. METHODOLY FOLLOWED IN SDR

The methodology followed in this paper is chosen in such a way
that the paper looks more appropriate and resembles very
Fig 1 Standalone wireless networks closely to the software approach followed.
Especially this paper is meant to be entirely simulation; a
In a coordinated wireless network, “thin” access points, or radio hardware implementation would be more realistic.
ports, have much simpler responsibilities most of the heavy
lifting is performed by a centralized controller, which handles
functions such as roaming, authentication, 3.1 Issues regarding the implementation of
encryption/decryption, load balancing, RF monitoring, this paper and final implementation
performance monitoring and location services. Because The reasons for not going into hardware implementation for the
configuration is done once, at the controller, adding additional paper are as follows.
radios to cover new office areas is as simple as plugging them The hardware implementation for this paper takes
in. longer time, not possible to complete in a few months.
The hardware required for this paper is highly costly
and complex to operate. It demands complex
embedded systems and other resources such as
computing platforms running on Vx-Works.
Hardware implementation requires work to be done in
various fields and it requires assistance from a large
number of professionals.
Moreover this is an emerging technology and not very
commonly available so it would be difficult to obtain
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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

references for the model for its performance The other important reason for inability to calculate
evaluation in the real time functionalities. the through put of the system is that many of this
The implementation is done in SIMULINK because of the implementations are done in special Embedded
following reasons. platforms such as a PC running on Vx-Works. Vx-
The graphical user interface provided by the Simulink Works supports very small response time than
will be better to demonstrate the functioning of Windows operation systems offer so there will be fall
different key components such as CPUs and the in the performance of the system if it was
DSPs. implemented in Windows. This is the reason why Vx-
With MATLAB and SIMULINK it will be easy to Works running on a power PC is used as a standard
implement various Base Band signal operations. system for 4.5 Generation Fighter Aircrafts like
The S-function builder blocks can be used to function Rafale, F-18 Phalcon, Su-30 MKI etc.
exactly as we programmed them so the various The final goal of this paper is to demonstrate the
programming methodologies can be implemented on functionality of all the software blocks designed, as
them. this includes the transmission of large frames in real
The paper closely resembles to the Hardware time, it is not possible to visualize outputs at different
Implementation. stages completely only a part of the output is tapped
separately and plotted

3.2 Changes in the course of methodology

and the final methodology 3.3 About the final design model
The initial methodology proposed and the reasons for the All the key components such as CPU and the DSPs
deviation from the initial methodology proposed are stated are modelled into S-Function Builder blocks.
briefly as follows. The outputs at the various levels of the model are
In the initial methodology it was planned to tapped and are displayed for viewing.
implement a model for Software defined radio which The major results obtained are Different modulation
supports WLAN and Personal Handy phone Systems techniques for the generation of the output and the
standards was proposed but later the PHS mode was distortion the noise produces on this signals while
omitted and Bluetooth was included. The reason for travelling through the transmission medium, the
this is PHS mode is not very much popular and no modelled channel block in this paper.
proper references are available for it as it is being SNR of the designed block for various levels of
used by relatively few people in Far East Asia. distortion.
Initially the goal was to obtain the results for the Key algorithms for the above mentioned schemes are
throughput for the system designed, but it became written and are included in a main program which
impossible due to problem with the SIMULINK tool. controls them and the overall functionality of each
The time for the simulation had to be reduced to half block.
the sampling time to transmit arrays of data in parallel Man Machine Interface is provided through a group of
without any duplication of the transmitted data. Using control signals provided to the CPU and CPU controls
this reduced simulation time throughput of the system the DSPs in turn.
can’t be verified. The Pulse shaping, the functionality of the pre/post
Finally it was decided to implement various processors is emitted.
algorithms for FEC, CRC, encoding and decode the The noise is not added as a noise block, the signals are
raw data bits and verify their functioning bit imported separately to the workspace and then noise
transmitting the frames over a communication is added in MATLAB.
channel.
The channel was modelled as Nakagami channel as 4. IMPLEMENTATION PROCEDURE
stated in the previous chapter. The implementation of the paper should cover various
According to the specifications given in the IEEE algorithms and the steps followed to generate various signals
802.11 standards Convolutional codes were selected using different modulation schemes
for FEC for WLAN and according to the Bluetooth
standards Hamming codes are used as FEC.
CRC generation algorithm is implemented for both 4.1 Various implementations at various levels
the standards. The various implementations which occur at various levels for
Sample packets are designed are transmitted across to both the standards are given below.
verify the functioning of the designed protocols. 4.1.1 WLAN
A limited implementation of WEP algorithm is Firstly CRC is to be calculated for the generated data.
shown. CRC-16 and CRC-32 are to be generated as both are
And the most important of it is OFDM technology a used in the WLAN frame.
single channel or a sub-carrier is transmitted as the Secondly the raw bits generated including the CRC
model consists of only two transreceivers. are encoded using source coding technique. The ideal
Only one way communication is fully implemented source coding technique is LZ-78 or the Lempel-Ziv
through all the stages, that is uplink from transmitter coding, but it has some limitations for implementing
to access point is implemented through all the details programming languages like C or even MATLAB
and signal processing operations. The only reason for compiler itself. The alternative to this is Run length
this is the memory constraints; SIMULINK cannot coding, but this may not be very much efficient.
assign any given number of the variables at any given Then the Forward error correction codes should come
time. The down link is connected directly for the into play according to the specifications of IEEE
transfer of raw data bits.

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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

802.11a standards the FEC used is convolutional Repeat this procedure until the code word reaches its
codes and are decoded using VERTIBRE algorithm. maximum length.
Then next comes modulation scheme, the modulation The main drawback of this procedure is that the
scheme used for WLAN is simple BPSK modulation. maximum length of the code word would be the
Then the next thing is adding noise to the modulated maximum or the greatest integer value and it cannot
signal, this is done by adding the AWGN through exceed it.
AWGN noise block and fading through importing the
signals to workspace, adding the noise in MATLAB 4.2.1.2 CRC Generation
and sending them back to the Simulink. Take the bits for which CRC is to be generated and
Then at the receivers end a Gaussian filter is used to store them in an array.
filter the AWGN noise, and since the fading is flat Select an appropriate polynomial for 16 bit and 32 bit
and it does not affect the signal much. CRC.
At the receiver the signal is again properly sampled Define another array of length 15 for 16 bit CRC and
and the timing mismatch is corrected if it is present 31 for 32 bit CRC; store the polynomial also into
anywhere. another array.
This is very important to note that the receiver XOR the first 16 bits of the data and store the
operations are completely different in a software remainder in the array just created for them.
defined radio. The reason is that all the Baseband Next add the next bit of the data array to the
Operations are done in software platform rather than remainder array as a last element and do the division
different sorts of hardware. It follows that the once again and repeat the above steps.
analogue to digital converter used at the receiver is Do these till the data is completely divided and the
connected directly to the DSP at the Front End of the CRC is obtained.
receiver. Normally a Pre/post processor should be
involved but this is omitted in the model.
4.2.1.3 Convolutional codes
According to the state transition diagram developed
4.1.2 Bluetooth on paper define a function which has a present state at
Relatively easy to implement. (0,0) and generates the output states according to the
Frame format for Bluetooth is simple compared to the state transition diagram.
WLAN protocol and moreover the only thing which is This is a very precise algorithm which works very
going to be implemented in the Bluetooth is point to efficiently and which is easy to implement.
point connection and no other complex tasks.
The decoding is done through Viterbi algorithm.
Bluetooth standard does not state any source coding
since the Bluetooth frame is relatively smaller.
Hamming codes are used for Bluetooth FEC. 4.2.1.4 BPSK Modulation.
Their channel modelling will be similar to that of Buffer all the data to be transmitted into an array.
WLAN but the SNR will differ and relatively the Pre define the carrier wave with suitable frequency of
Bluetooth channel suffers from less attenuation than the operation.
compared to the normal WLAN channel. Now if the coming input is 1 transmit the same wave
The key aspect in implementing Bluetooth is and if the input is zero phases shift the wave by
authentication. A simple authentication algorithm is simply multiplying it with -1.
used to implement the Bluetooth technology. This will give raise to BPSK modulation where one
symbol is represented by on wave.
4.2 Detailed implementation of above
4.2.1.5 Addition of noise
mentioned algorithms AWGN noise is added by passing the signal through
4.2.1 WLAN protocol AWGN block.
4.2.1.1 Source coding The fading is done by importing the signal to
Source coding is implemented using Lempel-Ziv coding. The workspace and modeling the samples of the input
detailed algorithm is given below. signals by the given Nakagami distribution.
Input all the bits coming from the source and store
them in an array. 4.2.1.6 Bluetooth
Increment the values of the bits by one, that is logical The important algorithms in Bluetooth are CRC, GFSK and the
one is represented as 2 and zero as 1. process of authentication.
Start three more arrays one for the code book, other
for the index and other for the maximum length of the 4.2.2 GFSK Modulation
code word. Algorithm to implement GFSK modulation is given as follows.
Consider the first bit, add it to the code book and log It is similar to FSK modulation except that the
1 into the Zero index of the index. Gaussian filter is used to shape the pulses of logical
Input next number. If it is different add it to the code Zeros and Ones before they are passed onto the FSK
book and increment the index and if it is same add modulator.
that number and the next number to the last two digits Here FSK generates two types of carrier waves and
of the third array, and the rest of the array must be according to the input data one wave is given to the
zeros. Multiply all the elements of the array with output for FSK modulation.
increasing powers of 10 starting from zero in the 4.2.2.1 Authentication
direction of right to left and add the result to the
second array of the code book.

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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

There are many algorithms for this purpose and one of the
common algorithms is, one node sends a challenge to the other
node.
The other node responds by sending back the same
received challenge for authentication from the first
node.
In this process this process is used for the process of
authentication.
As the Bluetooth is implemented only as one to one
communication there is no much complexity in Fig 4 Modulation scheme 2
implementing Bluetooth protocol as that of WLAN. BPSK modulation for the sample set of bit [1 0 0 1 1 1 0 1 1 0].
4.2.2.2 Hamming nodes
The generator matrix of a hamming code of [n,k] is a 5.2 Effect of noise on the BPSK modulation for
kXn matrix and the. The generator matrix for the dual
code is (n-k)Xk matrix.
different values of channel parameter m
The check matrix is an nXk matrix.
The K-bit message is multiplied by the generator
matrix and on the receiving end the generated code
word is again multiplied by the check matrix.
The decimal equivalent of the obtained number tells
us where the error has occurred.

5. RESULTS & DISCUSSION

The non-graphical results expected in this paper are summarized
as follows.
There are many coding techniques included in the Fig 5 BPSK modulation With m=1
model like convolutional codes, hamming codes etc.
The algorithms designed for the various coding
technologies are verified with given sample data and
are found to be correct.
All the verified algorithms are included in the
Simulink model successfully.
The graphical results of the paper include the following aspects.
There are two basic modulation schemes used in this
paper. BPSK and PSK. These schemes were plotted
for a given sample data and are included. Fig 6 BPSK modulation with m=2
The effect of noisy channel is also plotted and the
recovered signal is also plotted.
At last the BER curve for the Nakagami channel with
the specifications mentioned above is plotted.
The graphical results are included below.

5.1 Basic modulation schemes

The BPSK generated signals for a sample set of data at 1 MHz
Frequency is as follows.

Fig 7 BPSK modulation with m=3

.
Fig 3 Modulation scheme 1
BPSK modulation for sample set of bits[1 0 0 1 1 1 0 1 1 0].The Fig 8 BPSK modulation with m=4
sample PSK at 1 MHz and 2MHz is given below.
So from the above plots it is clear that as the value of m is
increasing the noise level of the signal also decreases.
Now the smoothened signal for m=4 is shown below

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 International Journal of Computer Applications (0975 – 8887)
Volume 4– No.8, August 2010

6. CONCLUTION
Transceivers for the communication standard can be
implemented in a pure software platform than the
prevailing architectures.
This implementation will narrow down the differences
between the equipment currently in the present day
market.
Users will be greatly benefited from the equipment
built using the SDR platform as they support multiple
Fig 9 Smoothened signal for m=4 communication standards with the same given
hardware.
The following inferences can be made. There will be no need of buying multiple
Since the fading is flat as explained in the chapter II, equipments for multiple purposes as one equipment
the characteristics of the signal are preserved and are can take care of all the things.
not distorted. Active research is being carried out in this area and
This clearly implies that impulse of the signal does much commercial SDR equipment for different
not change and the original message can be retrieved applications is available for commercial use. Presently
or the signal can be used for demodulation without their costs are very huge.
any problem. In the near future all the mobiles, talkies that are used
Small adjustments for the timing synchronization can will become more and more flexible and tend towards
be made in the receiver. SDR platform rather than the traditional architectures
Since an SDR platform is used it is very easy achieve being used now.
timing synchronization using various techniques. With the advancements made in VLSI and the
5.3 BER curve on m-Nakagami channel microprocessors fields the architecture of an SDR
becomes simplified rapidly.
A day will come where a single transceiver can act as
all in one and can be used as a mobile phone which
can support both GSM and CDMA, which can also be
connected to a WLAN access point, which has got
Bluetooth connectivity, which can receive FM signals
and work as FM radio etc.

7. ACKNOWLEDGMENT
I wish to thank all the co authors who have supported me to a
great extent. I also wish to thank VIT University for providing
us excellent support.

Fig 10 BER Curve for Nakagami-m Channel

The above graph is in accordance with the Nakagami-m
8. REFERENCES
Channel with the relation to the upper limit of probability of [1] Published paper in Computer “Communications” titled
error derived in the section 2.6 of Second Chapter. “Software Radio Reconfiguration
NOTE: Management”. By Klaus Moessner, Didier Bourse, Dieter
Some important aspects regarding the above reference curve are Greifendorf and Joerg Stammen dated 26th February 2002.
given below.
The above curve holds good for a receiver employing [2] Technical Brief on “Planning a Wireless Network” by
Soft Decision Vitabri decoding algorithm. ProCurve networking – Hp-innovative.
The above curve holds good BPSK and QPSK
modulations with bit rates of 6 Mbps and 12 Mbps [3] “IEEE 802.11 Wireless LAN Implemented on a software
only. defined radio with Hybrid Programmable Architecture”. IEEE
This curve is drawn by averaging of the upper limits transactions on Wireless communication dated 5, September
of the probabilities of the errors for 48 sub-carriers of 2005 by Takashi Shono, Yushi Shirato, Hiroyuki Shiba,
the OFDM wave. (Note: All the sub-carriers are Kazuhiro Uehara,, Katsuhiko Araki, and Masahiro Umehira.
treated independent waves and their individual BERs
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vary much and will be almost a constant). Brenner.
The curve changes if the modulation schemes are
changed or higher bit rates other than the bit rates [5] “Bluetooth protocol Architecture” by Riku Mettala.
mentioned are utilized.
Inferences drawn from the above graph. [6] Theses published on “Performance analysis of the IEEE
For all the values of m = 1, 2 & 3. SNR the paper is 802.11a WLAN standard optimum and sub optimum receiver in
modelled with an SNR of 10 dB and for m=4 the SNR frequency selective, slowly fading Nakagami channels with
is made to be 8. AWGN and pulsed noise jamming” by Christos Kalogrias.
We can clearly note that more power is required to
transmit the signals as fading condition (m parameter) [7] “Programmable SDR” CBIS 2007, by Chris Wasser.
increases in the channel

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