WO2017013628A1

WO2017013628A1 - System and method for multi-user detection in a wireless communication system

Info

Publication number: WO2017013628A1
Application number: PCT/IB2016/054382
Authority: WO
Inventors: Ranga Rao MATURI; Prabhakara Rao B
Original assignee: Maturi Ranga Rao
Priority date: 2015-07-22
Filing date: 2016-07-22
Publication date: 2017-01-26
Also published as: IN2015CH03776A

Abstract

Exemplary embodiments of the present disclosure are directed towards a method for multi-user detection (MUD) for code division multiple access (CDMA) system using elliptic curve cryptography (ECC). The method comprising sending at least one of the data signals by a plurality of users, modulating the at least one of the data signals; and filtering and combining the at least one of the data signals for a key generation.

Description

SYSTEM AND METHOD FOR MULTI-USER DETECTION IN A WIRELESS

COMMUNICATION SYSTEM

TECHNICAL FIELD

[001] The present disclosure generally relates to the field of telecommunication systems. More particularly, the present disclosure relates to a system and method for multi-user detection in a wireless communication network.

BACKGROUND

[002] Generally, most of the telecommunication devices are operated over a wireless communication network employing technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA). Generally, CDMA is the prominently used technology for wireless communications. The CDMA technology allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth. In this CDMA a special code is assigned for each transmitter for transmitting signal from one device to other.

[003] As a number of users in a CDMA system transmit data to the base station at the same time, it will be difficult for the CDMA system to transmit signals to number of users without interference. However interference occurs in the communication system and also there are chances of losing the signal.

[004] Although relatively specific problems have been discussed, it should be understood that the embodiments disclosed herein should not be limited to solving the specific problems identified in the background.

BRIEF SUMMARY

[005] The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

[006] Exemplary embodiments of the present disclosure are directed towards a method for multiuser detection (MUD) for code division multiple access (CDMA) system using elliptic curve cryptography (ECC).

[007] According to an exemplary aspect, the method includes sending at least one of the data signals by a plurality of users, modulating the at least one of the data signals and filtering and combining the at least one of the data signals for a key generation.

[008] According to an exemplary aspect, the method of key generation using elliptic curve cryptography includes generating a public key and a private key for at least one of the data signals and assigning the public key to a user, demodulating the received data signal to identify the correct data signal transmitted and encoding the transmitting data signal and transmitting the encoded data signal to the user.

[009] According to an exemplary aspect, the method includes encoding data signal and decoding using elliptic curve cryptography includes generating a public key and a private key for at least one of the data signals and assigning the public key to a user, demodulating the received data signal to identify the correct data signal transmitted, encoding the transmitting data signal and transmitting the encoded data signal to the user and decoding the received data signal by the user and filtered to reduce the noise and interference.

BRIEF DESCRIPTION OF DRAWINGS

[010] Other objects and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments, in conjunction with the accompanying drawings, wherein like reference numerals have been used to designate like elements, and wherein:

[011] FIG. 1 is a diagram depicting a system for multi user detection (MUD) for code division multiple access (CDMA), according to an exemplary embodiment of the present disclosure. [012] FIG. 2 is a block diagram depicting a system for multiuser detection (MUD) based code division multiple access (CDMA) using elliptic curve cryptography (ECC), according to an exemplary embodiment of the present disclosure.

[013] FIG. 3 is a flow diagram depicting a method for multiuser detection (MUD) in CDMA using elliptic curve cryptography, according to an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

[014] It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[015] The use of "including", "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Further, the use of terms "first", "second", and "third", and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

[016] According to a non limiting exemplary embodiment of the present disclosure, a system and method for multi-user detection in a wireless communication network are disclosed.

[017] Referring to FIG. 1 is a diagram 100 depicting a system for multi user detection (MUD) for code division multiple access (CDMA), according to an exemplary embodiment of the present disclosure. [018] The system 100 includes handheld devices 102a, 102b ... 102n of users at sending end, and the handheld devices 108a, and 108b ... 108n of users at receiving end. The handheld devices may include a mobile phone, tablet, and the like, without limiting the scope of the disclosure. The data signals 104a, 104b ... 104n are transmitted from handheld devices 102a, 102b ... 102n of users at sending end to the handheld devices 108a, 108b ... 108n of users at receiving end through a channel 105. The data signal may include any communication signal, without limiting the scope of the disclosure. The data signals 104a, 104b ... 104n transmitted are separately modulated and filtered. The data signals 104a, 104b ... 104n are combined after filtration to generate a key.

[019] The key generation process is initiated using elliptic curve cryptography, for example. The public and private keys are generated for each data signals 104a, 104b ... 104n transmitted and the public key is given to the receiving user. The public key is to identify the appropriate transmitted signal sent from the handheld devices 102a, 102b ... 102n of users at sending end. The public key is sent to the receiving user and encoding operation is performed for the transmitted signal. In the encoding operation the data signal transmitted is converted into a specific form to receive the sent signal.

[020] Referring to FIG. 2 is a block diagram 200 depicting a system for multiuser detection (MUD) based code division multiple access (CDMA) using elliptic curve cryptography (ECC), according to an exemplary embodiment of the present disclosure. The system 200 includes handheld devices 102a, 102b ... 102n of users at sending end transmitting data signals 104a, 104b ... 104n through the same channel 105 and the data signals 104a, 104b ... 104n are modulated separately. The data signals 104a, 104b ... 104n are filtered and the entire signal is combined for a key generation.

[021] The steps for key generation using ECC:

Step 1 : Select a point R (x, y) on the elliptic curve.

Step 2: Select a prime number p and integer values for a and b.

Step 3: Select one point in the curve Ri = (x, , y ) Step 4: Select k value which is a random integer value. Step 5: Calculate Ra using the formula R2 = (xj , ) = k * Ri Step 6: Use Ri and R₂ as public key and k as private key.

[022] The public and private keys are generated for each data signals 104a, 104b ... 104n transmitted and the public key is given to the receiving user. The public key is to identify the appropriate signal sent from the transmitting unit. The public key is sent to the receiving user and encoding operation is performed for the transmitting signal. The encoding and decoding operations are done by transmitter.

[023] The steps for the encoding operation are as follows:

Step 1 : Select h value in plain text p, which is a random integer value. Step 2: Calculate cipher text value using the equation given below, q = h * R!

Cj = ( Xpi , y_pi ) + h * R2 Step 3: Generate a unique matrix from R

Step 4: Take unique elements present in the R matrix and calculate the sum of the unique elements i.e. d .

Step 5: Find the nearest square value of the sum value and take square root of the nearest square value i.e. f.

Step 6: Create a new matrix U with size f X f using the equations given below.

U(i*M₊j) » R (0,0) ; if i U(i*M+j) » R (i,j) ; if R(i,j) «U

[024] The encoded data signal is received to the user at receiving end and decoded using ECC. [025] The steps for receiving the data signal by the user are:

m

where, s_m is the signature waveform of the Μ^Λ user. The formula to calculate signature waveform is as follows,

30 ^sm (0 =∑^bm -^pr (^t - ^m-^Ci ) m—0 where, t is the bit period, C_; is the chip interval, d_m is the input bit of the M"¹ user, A_m is the received amplitude of the M* user, g(t) is the additive white Gaussian noise.

The ECC the signature sequences is

m

Where, N is the length of the signature sequence.

The ECC cross-correlation matrix is defined as follows,

[026] The data signal is received and demodulated to get appropriate data signal transmitted from the user at sending end.

[027] The steps for decoding are as follows:

Step 1 : Calculate P using the private key g, after receiving the cipher text Cj and C i as follows:

(xpi . yp_. ) = Cj - ( g *Ci )

Step 2: Read the characters from the coordinates (Xpj , ypi )■

[028] The next step after decoding operation is filtering. In the filtering process noise present in the data signal are reduced to obtain the exact data signal.

[029] Referring to FIG. 3 is a flow diagram 300 depicting a method for MUD in CDMA using elliptic curve cryptography, according to an exemplary embodiment of the present disclosure. The method starts at step 302 by transmitting the data signals by the user at sending end. The method continues to next step 304 by modulating the transmitted data signals. The method continues to next step 306 by filtering and combining the transmitted data signals for a key generation. The method continues to next step 308 by generating a public key and a private key for the transmitting data signals. The method continues to next step 310 by assigning the public key to the user at receiving end. The method continues to next step 312 by demodulating the received data signal to identify the correct data signal transmitted. The method continues to next step 314 by encoding the transmitted data signal. The method continues to next step 316 by decoding the received data signal by the user at receiving end and filtered to reduce the noise and interference.

[030] Although the present disclosure has been described in terms of certain preferred embodiments and illustrations thereof, other embodiments and modifications to preferred embodiments may be possible that are within the principles and spirit of the invention. The above descriptions and figures are therefore to be regarded as illustrative and not restrictive.

[031] Thus the scope of the present disclosure is defined by the appended claims and includes both combinations and sub combinations of the various features described herein above as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

CLAIMS What is claimed is:

1. A method for multi-user detection(MUD) for code division multiple access (CDMA) system using elliptic curve cryptography (ECC), the method comprising: sending at least one of the data signals by a plurality of users; modulating the at least one of the data signals; and filtering and combining the at least one of the data signals for a key generation.

2. The method of claim 1, whereby key generation using elliptic curve cryptography comprising: generating a public key and a private key for at least one of the data signals and assigning the public key to a user; demodulating the received data signal to identify the correct data signal transmitted; and encoding the transmitting data signal and transmitting the encoded data signal to the user.

3. The method of claim 2, whereby encoding data signal and decoding using elliptic curve cryptography comprising: generating a public key and a private key for at least one of the data signals and assigning the public key to a user; demodulating the received data signal to identify the correct data signal transmitted; encoding the transmitting data signal and transmitting the encoded data signal to the user; and decoding the received data signal by the user and filtered to reduce the noise and interference.

4. The method of claim 2, wherein the public key is generated using elliptic curve cryptography.

5. The method of claim 2, wherein the filtering is done to reduce the noise and interference and to obtain the exact data signal.

6. The method of claim 3, wherein the encoding and decoding operations are done by transmitter.