AU2021105611A4 - System & method for cognitive radio link monitoring & controlling in an ofdm based wireless communication system using cognitive radio-based internet of things - Google Patents

Abstract

SYSTEM & METHOD FOR COGNITIVE RADIO LINK MONITORING & CONTROLLING IN AN OFDM BASED WIRELESS COMMUNICATION SYSTEM USING COGNITIVE RADIO-BASED INTERNET OF THINGS ABSTRACT The present invention is related to system & method for cognitive radio link monitoring & controlling in an OFDM based wireless communication system using cognitive radio-based internet of things. The objective of present invention is to solve the abnormalities presented in the prior art techniques related to OFDM based wireless communication. The invention present a new Physical Layer Encryption Scheme specifically targeted for OFDM systems. Encryption would be performed on the time domain OFDM symbols as shown in Figure 4. This would be equivalent to performing a nonlinear masking on the Frequency Domain Signals. The key streams required for encryption would be efficiently reduced.. 21 DRAWINGS Constellation mapping 4"IC s[nl] FFT-1 serial 9 to parall J 71m DAC FIGURE 1 22

Description

DRAWINGS

Constellation mapping

4"IC s[nl] FFT-1 serial 9 to parall

J 71m DAC

FIGURE 1

SYSTEM & METHOD FOR COGNITIVE RADIO LINK MONITORING & CONTROLLING IN AN OFDM BASED WIRELESS COMMUNICATION SYSTEM USING COGNITIVE RADIO-BASED INTERNET OF THINGS FIELD OF INVENTION

[001]. The present invention relates to the technical field of OFDM

based wireless communication,

[002]. The present invention relates to the field of monitoring

& controlling in an OFDM based wireless communication.

[003]. particularly, the present invention relates to the field of wireless

communication system using cognitive radio-based internet of things.

[004]. More particularly, the present invention is related to system &

method for cognitive radio link monitoring & controlling in an OFDM

based wireless communication system using cognitive radio-based

internet of things.

BACKGROUND & PRIOR ART

[005]. The subject matter discussed in the background section should

not be assumed to be prior art merely as a result of its mention in the

background section. Similarly, a problem mentioned in the

background section or associated with the subject matter of the

background section should not be assumed to have been previously

recognized in the prior art. The subject matter in the background

section merely represents different approaches, which in-and-of

themselves may also be inventions.

[006]. Orthogonal frequency-division multiplexing (OFDM) is a Multicarrier

Modulation Technique. OFDM is essentially identical to coded OFDM

(COFDM) and discrete multi-tone modulation (DMT), and is a frequency

division multiplexing (FDM) scheme used as a digital multi-carrier

modulation method. OFDM systems break the available bandwidth into

many narrow sub-carriers and transmit the data in the parallel streams.

Each subcarrier is modulated using varying levels of QAM Modulation,

e.g. QPSK, QAM, 64 QAM or possibly higher orders depending on Signal

Quality [3]. Each OFDM symbol is a Linear Combination of instantaneous

signals on each of the subcarriers in the respective channel. OFDM is a

special case of FDM that uses overlapped sub channels to circumvent the

inefficiency of the conventional FDM System where the orthogonality between the modulated subcarriers needs to be ensured by the proper choice of Subcarrier Spacing. OFDM provides robustness against

Frequency Selective Fading and Narrow Interference [9].

[007]. The modulation [Figurel] and demodulation [Figure2] of OFDM

signals can be implemented in hardware efficiently using Inverse Fast

Fourier Transform (IFFT) and Fast Fourier Transform (FFT) respectively.

Consequently, OFDM has been adopted in many standards. This include

next generation mobile technologies 3GPP LTE [3],4G, IEEE 802.16 Wi

Max [6], digital audio broadcasting (DAB) [4] and digital video

broadcasting (DVB) [5] just to name a few.

The advantages of OFDM include:

[008]. High spectral efficiency

[009]. Can easily adapt to severe channel conditions without complex

time-domain equalization

[0010]. Robust against narrow-band co-channel interference

[0011]. Robust against ISI and fading caused by Multipath Propagation

[0012]. Eliminate inter-symbol interference (ISI) with the help of Cyclic

Prefix

[0013]. Efficient implementation using Fast Fourier Transform (FFT)

[0014]. Low sensitivity to Time Synchronization Errors.

[0015]. No requirement of Tuned sub-channel receiver filters

[0016]. Facilitates Single Frequency Networks

[0017]. Channel equalization becomes much simpler compared to single

carrier (SC) systems

[0018]. Achieves high data rate with great bandwidth efficiency and

flexible underlying modulations

The disadvantages of OFDM include:

[0019]. Sensitive to Doppler shift

[0020]. Sensitive to Frequency Synchronization Problems

[0021]. High peak-to-average-power ratio (PAPR)

[0022]. Loss of efficiency caused by cyclic prefix/guard interval.

[0023]. Double Sideband Modulation of each sub-carrier causes Lower

Spectral Efficiency and higher transmitter power requirements for

equivalent coverage as compared to VSB modulation

[0024]. In a Wireless Communication Paradigm Stream Cipher

Encryptions are usually performed by independently encrypting a

message bit with a key stream bit through exclusive OR (XOR)

operations. The required key stream length is the same as the

message length. This might be problematic in a high speed data

transmission application with constrained devices. The rate of

generation of key streams might not keep up with the transmission

rate. This is a generic method and can be applied to any

communication systems.

[0025]. The work is proposed for a novel Physical Layer Encryption

Scheme especially for OFDM systems, which would require

comparatively much lesser key streams as compared to other

proposed encryption schemes in the literature. The proposed work

would be entirely based on preserving the orthogonality in OFDM

symbols as we know that destroying the orthogonality would create

inter-carrier interferences and this would affect symbols on all the

subcarriers subsequently causing higher symbol error rate (SER) and

higher bit error rate (BER) for the adversary. The encryption would

be performed on the time domain OFDM symbols, which is

equivalent to performing a nonlinear masking in the frequency domain. This intended scheme would introduce non-linear distortions for the adversary when he would try to perform the demodulation by direct computing DFT on the received encrypted

OFDM symbols without the decryption and hence the intended

proposal would provide more Cryptographic Strength to the existing

Physical Layer of OFDM Systems. This would definitely help the

research fraternity in the industry and the academia to analyze their

current state of physical layer encryption standards for OFDM

systems and to enhance or improve their goals for a future Secured

OFDM Systems.

[0026]. Groupings of alternative elements or embodiments of the invention

disclosed herein are not to be construed as limitations. Each group member

can be referred to and claimed individually or in any combination with

other members of the group or other elements found herein. One or more

members of a group can be included in, or deleted from, a group for

reasons of convenience and/or patentability. When any such inclusion or

deletion occurs, the specification is herein deemed to contain the group as

modified thus fulfilling the written description of all Markus groups used

in the appended claims.

[0027]. As used in the description herein and throughout the claims that

follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

[0028]. The recitation of ranges of values herein is merely intended to serve as

a shorthand method of referring individually to each separate value falling

within the range. Unless otherwise indicated herein, each individual value is

incorporated into the specification as if it were individually recited herein.

All methods described herein can be performed in any suitable order unless

otherwise indicated herein or otherwise clearly contradicted by context.

[0029]. The use of any and all examples, or exemplary language (e.g. "such

as") provided with respect to certain embodiments herein is intended merely

to better illuminate the invention and does not pose a limitation on the scope

of the invention otherwise claimed. No language in the specification should

be construed as indicating any non-claimed element essential to the practice

of the invention.

[0030]. The above information disclosed in this Background section is

only for enhancement of understanding of the background of the

invention and therefore it may contain information that does not form

the prior art that is already known in this country to a person of

ordinary skill in the art.

SUMMARY

[0031]. The present invention mainly cures and solves the technical

problems existing in the prior art. In response to these problems, the

present invention provides system & method for cognitive radio link

monitoring & controlling in an OFDM based wireless communication

system using cognitive radio-based internet of things.

[0032]. As one aspect of the present invention relates to A system for

cognitive radio link monitoring & controlling in an OFDM based

wireless communication system using cognitive radio based internet

of things, wherein the A bitwise XOR are performed between

messages and key streams before the subcarrier mapping and the

IDFT block, the intended OFDM Encryption Scheme encrypt the

message by term-wise multiplication of each of the in-phase and

quadrature components of time domain OFDM symbols with key

streams a and b, where a and b are{-1, 1} valued binary sequences, wherein In stream cipher encryptions, each message bit is independently encrypted with a key stream bit through XOR operation to produce one Cipher-text bit, wherein a non-linear distortions for the adversary a demodulation by direct computing

DFT is performed on the received encrypted OFDM symbols

without the decryption.

OBJECTIVE OF THE INVENTION

[0033]. The principal objective of the present invention is to provide

system & method for cognitive radio link monitoring & controlling in

an OFDM based wireless communication system using cognitive

radio-based internet of things.

[0034]. The objective of the present invention is to present a new

Physical Layer Encryption Scheme specifically targeted for OFDM

systems. Encryption would be performed on the time domain OFDM

symbols as shown in Figure 4. This would be equivalent to

performing a nonlinear masking on the Frequency Domain Signals.

The key streams required for encryption would be efficiently

reduced.

BRIEF DESCRIPTION OF DRAWINGS

[0035]. Further clarify various aspects of some example embodiments of

the present invention, a more particular description of the invention

will be rendered by reference to specific embodiments thereof which

are illustrated in the appended drawings. It is appreciated that these

drawings depict only illustrated embodiments of the invention and are

therefore not to be considered limiting of its scope. The invention will

be described and explained with additional specificity and detail

through the use of the accompanying drawings.

[0036]. In order that the advantages of the present invention will be

easily understood, a detailed description of the invention is discussed

below in conjunction with the appended drawings, which, however,

should not be considered to limit the scope of the invention to the

accompanying drawings, in which:

[0037]. Figure 1: Ideal OFDM Transmitter.

[0038]. Figure 2: Ideal OFDM Receiver.

[0039]. Figure 3: Ideal OFDM Spectrum.

[0040]. Figure 4: OFDM - Parallel Symbol Transmissions.

[0041]. Figure 5: Standard OFDM Encryption Scheme.

[0042]. Figure 6: Standard OFDM Decryption Scheme.

DETAIL DESCRIPTION

[0043]. The present invention discloses system & method for cognitive

radio link monitoring & controlling in an OFDM based wireless

communication system using cognitive radio-based internet of things.

[0044]. Figure 1 shows the exemplary representation of system

& method for cognitive radio link monitoring & controlling in an OFDM

based wireless communication system using cognitive radio-based

internet of things, according to the present invention.

[0045]. Although the present disclosure has been described with the

purpose of two smart frameworks for providing privacy and protection

in block chain based private transactions using cloud computing

approach, it should be appreciated that the same has been done merely

to illustrate the invention in an exemplary manner and to highlight any

other purpose or function for which explained structures or

configurations could be used and is covered within the scope of the

present disclosure.

[0046]. An system & method for cognitive radio link monitoring

& controlling in an OFDM based wireless communication system using

cognitive radio-based internet of things is disclosed.

[0047]. In literature the Modulation and Demodulation of the OFDM

signals can be implemented in hardware as shown in efficiently

using Inverse Fast Fourier Transform (IFFT) and

[0048]. Fast Fourier Transform (FFT) respectively. Consequently,

OFDM had been adopted in many

[0049]. Standards which include the next generation Mobile

Technologies 3GPP LTE, IEEE 802.16 Wi- Max and Digital Audio

Broadcasting (DAB) [2][4]. In a Wireless Communication Setting,

Stream Ciphers are usually chosen for the purpose of encryption to

ensure the secrecy of the message. This is primarily because data

transmission over Wireless Channels is error prone compared to

wired transmissions [5].

[0050]. In stream cipher encryptions, each message bit is independently

encrypted with a key stream bit through XOR operation to produce

one Cipher-text bit.

[0051]. At the receiver Figure 6, the same XOR operation between the

Cipher-text bit and the key stream bit is performed to recover the

message.

[0052]. There will not be any error propagation in the decoding process.

This differs from block cipher encryption. In block cipher

encryptions, one bit error in the Cipher-text will cause the entire

block of messages to be incorrectly decoded.

[0053]. Therefore, one can either choose to use a Stream Cipher to

encrypt directly or convert a block cipher into stream cipher

through Counter (CTR) Mode or Cipher Feedback (CFB) Mode

then perform the encryption.

[0054]. In order to produce one bit of Cipher-text the proposed schemes

would require one bit of key stream. This could potentially create

problems in a high speed data transmission application with

constrained devices.

[0055]. For instance, in the next generation mobile 3GPP LTE standard,

it has been designed to meet a downlink (DL) peak data rate of 300

Mb/s (with 4 antennas and 64-QAM modulations) [3]. As a result,

the key streams generation rate has to be the same.

[0056]. Assuming the encryption cipher is AES used in counter mode,

to the best of my knowledge, even though the performance of AES

[7] can vary from 2.56 Gb/s to 62.6 Gb/s depending on the

implementations, this would require a hardware of 34.5 Kgates and

979.3 Kgates respectively

.

[0057]. This would be impractical with constrained devices such as

mobiles. The smallest AES implementation requires 2.4 Kgates,

but it can only generate key streams at a rate of 57 Kb/s . This is

not nearly sufficient to meet the requirement set forth by LTE.

[0058]. In the intended proposal, a novel Physical Layer OFDM

Encryption Scheme is proposed. Unlike the conventional encryption

schemes in the current literature where bitwise XOR are performed

between messages and key streams before the subcarrier mapping

and the IDFT block, the intended OFDM Encryption Scheme would

encrypt the message by term-wise multiplication of each of the in

phase and quadrature components of time domain OFDM symbols

with key streams a and b, where a and b are {-1, 1} valued binary

sequences.

[0059]. This would introduce the non- linear distortions for the

adversary whenever we try to perform the demodulation by direct

computing DFT on the received encrypted OFDM symbols without

the decryption. In the conventional schemes in the current literature,

knowing one bit of key stream will guarantee the recovery of one bit

message as correct decoding of any message bits relies on all time

domain signals to be correct.

[0060]. Apart from this in the conventional schemes, the numbers of key

streams required for encryption are equal to the number of message

bits, which would depend on the underlying subcarrier modulation.

However in the intended OFDM Encryption Scheme, the number of

key streams required is 2 bits per subcarrier regardless of r. When (r

> 2), the efficiency of intended OFDM Encryption Scheme would be

greater than one implying that less key streams are required to

encrypt messages [2].

[0061]. Finally the intended OFDM Encryption Scheme would be

substantiated with the efficient and self-proven simulation results in

comparison with the conventional schemes with QPSK modulations.

[0062]. The simulation results would also highlight the superior

performance with the higher modulation schemes while using the

same key stream length.

[0063]. The research work would also be substantiated with the highly

resistant key stream compromises existing in the current schemes

and would also underline the FFT size independence factor in the

research proposal..

[0064]. . The figures and the foregoing description give examples of

embodiments. Those skilled in the art will appreciate that one or

more of the described elements may well be combined into a single

functional element. Alternatively, certain elements may be split into

multiple functional elements. Elements from one embodiment may

be added to another embodiment.

[0065]. For example, order of processes described herein may be

changed and are not limited to the manner described herein.

Moreover, the actions of any block diagram need not be

implemented in the order shown; nor do all of the acts need to be

necessarily performed.

[0066]. Also, those acts that are not dependent on other acts may be

performed in parallel with the other acts. The scope of embodiments

is by no means limited by these specific examples.

[0067]. Although implementations of the invention have been described

in a language specific to structural features and/or methods, it is to

be understood that the appended claims are not necessarily limited to

the specific features or methods described. Rather, the specific

features and methods are disclosed as examples of implementations

of the invention.

Claims (5)

CLAIMS I/We claim:

1. A system for cognitive radio link monitoring

& controlling in an OFDM based wireless communication system using cognitive radio based internet of things, wherein the

A bitwise XOR are performed between messages and key streams before the subcarrier mapping and the IDFT block, the intended OFDM Encryption Scheme encrypt the message by term-wise multiplication of each of the in-phase and quadrature components of time domain OFDM symbols with key streams a and b, where a and b are {-1, 1} valued binary sequences, wherein In stream cipher encryptions, each message bit is independently encrypted with a key stream bit through XOR operation to produce one Cipher-text bit, wherein a non-linear distortions for the adversary a demodulation by direct computing DFT is performed on the received encrypted OFDM symbols without the decryption.

2. The system for cognitive radio link monitoring

& controlling in an OFDM based wireless communication system using cognitive radio based internet of things as claimed in claim 1, the same XOR operation between the Cipher-text bit and the key stream bit is performed to recover the message, there will not be any error propagation in the decoding process, this differs from block cipher encryption.

3. The system for cognitive radio link monitoring

& controlling in an OFDM based wireless communication system using cognitive radio based internet of things as claimed in claim 1, Wherein the numbers of key streams required for encryption are equal to the number of message bits, which would depend on the underlying subcarrier modulation.

4. The system for cognitive radio link monitoring &

controlling in an OFDM based wireless communication system using cognitive radio based internet of things as claimed in claim 1, Wherein the number of key streams required is 2 bits per subcarrier regardless of r. When (r > 2), the efficiency of intended OFDM Encryption Scheme would be greater than one implying that less key streams are required to encrypt messages.

5. The system for cognitive radio link monitoring

& controlling in an OFDM based wireless communication system using cognitive radio based internet of things as claimed in claim 1, highlight the superior performance with the higher modulation schemes while using the same key stream length, wherein the highly resistant key stream compromises existing in the current schemes and would underline the FFT size independence factor.