SPECTRAL EFFICIENCY OF SELECTION COMBINER UNDER NAKAGAMIM FADING CHANNELS

Abstract

ABSTRACT The present invention provides a closed-form expressions for the spectral efficiency over Nakagami-m fading channels under different adaptive transmission schemes with and without diversity combining.

Specification

Description:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)



Title: SPECTRAL EFFICIENCY OF SELECTION COMBINER UNDER NAKAGAMIM FADING CHANNELS


APPLICANT DETAILS:
(a) NAME: GRAPHIC ERA DEEMED TO BE UNIVERSITY
(b) NATIONALITY: Indian
(c) ADDRESS: 566/6, Bell Road, Society Area, Clement Town, Dehradun - 248002,
Uttarakhand, India








PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

SPECTRAL EFFICIENCY OF SELECTION COMBINER UNDER NAKAGAMIM FADING CHANNELS
Field of Invention:
The present invention relates to a closed-form expressions for the spectral efficiency over Nakagami-m fading channels under different adaptive transmission schemes with and without diversity combining.

Background of the Invention:
The following background discussion includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication expressly or implicitly referenced is prior art.
Currently, many research on existing adaptive communication schemes are conducted by related people in terms of improving system throughput and spectral efficiency. For example, US20190044246A1 discloses a system for controlling an interaction of a surface with an impinging electromagnetic wave is provided. The system comprises a surface comprising a plurality of controllable elements, wherein each of the controllable elements is configured to adjust its electromagnetic behavior based on a control signal received by the controllable element, a sensing unit configured to detect a state of an environment of the surface and/or one or more wave attributes of an electromagnetic wave impinging on the surface, a control unit configured to determine, based on the detected state of the environment and/or the one or more wave attributes, a control state of the controllable elements, in which the electromagnetic behavior of the controllable elements is adjusted such that the surface interacts with the impinging electromagnetic wave in a predefined manner, and an adjusting unit configured to determine.
Further, US10171194B2 discloses a system and method are provided wherein one or more femtocell base stations are deployed within a range of a cellular base station and utilize substantially the same frequency band as the cellular base station. Each femtocell base station may be configured to employ one or more interference avoidance techniques such that coexistence between the cellular and the corresponding femtocell base station is enabled. The interference avoidance techniques employed may include use of randomized time or frequency hopping; randomly selecting a predetermined number, or identifying one or more unutilized, frequency subchannels for signal transmission; using two or more transmit, and two or more receive antennas; nulling one or more transmissions in a direction of a nearby cellular base station user; handing off at least one cellular user to one of the femtocell base stations and vice versa; and/or reducing the transmission power of at least one femtocell base station.
However, none of the documents provide the closed-form expressions for the spectral efficiency over Nakagami-m fading channels under different adaptive transmission schemes with and without diversity combining.

Object(s) of the present invention:
The primary objective of the present invention is to overcome the drawback associated with prior art.
An object of the present invention is to provide the closed-form expressions for the spectral efficiency over Nakagami-m fading channels under different adaptive transmission schemes with and without diversity combining.

Summary of the Invention:
In an aspect the present invention provides a method of spectral efficiency of selection combiner under Nakagamim fading channels comprising steps of:
a) evaluating the spectral efficiency without diversity for different fading conditions; and
b) evaluating the spectral efficiency using the simplest diversity combining method i.e., Selection Combining (SC), for different fading conditions.
In an embodiment, the comparative analysis has been done with dual and three-branch diversity under different fading conditions.
In an embodiment, the spectral efficiency is evaluated under optimum rate adaptation scheme being less complex.
In an embodiment, after optimum rate adaptation an optimum simultaneous power and rate adaptation (OPRA) is used for spectral analysis.
In an embodiment, after OPRA adaptation scheme a Channel inversion with fixed rate (CIFR) is used for spectral analysis.

Brief description of Drawings:
The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, explain the disclosed principles. The reference numbers are used throughout the figures to describe the features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and regarding the accompanying figures, in which
Figure 1: illustrates Spectral efficiency v/s avg. received SNR under ORA scheme with no diversity SC.
Figure 2: illustrates the comparative analysis of Spectral efficiency v/s avg. received SNR under ORA scheme with different number of diverse branches.
Figure 3: illustrates the comparative analysis of Spectral efficiency v/s avg. received SNR under CIFR scheme with different number of diverse branches.
Figure 4: illustrates the spectral efficiency v/s avg. received SNR under OPRA scheme with no diversity SC.
Figure 5: illustrates comparative analysis of Spectral efficiency v/s avg. received SNR under OPRA scheme with different number of diverse branches.
Figure 6: illustrates spectral efficiency v/s average received SNR of No diversity (with m = 2) with different adaptive transmission schemes.
Figure 7: illustrates spectral efficiency v/s average received SNR of Dualbranch diversity (with m = 0.5 and 1) with different adaptive transmission schemes.
Figure 8: illustrates spectral efficiency v/s average received SNR of Threebranch diversity (with m = 0.5, 1 and 2) with different adaptive transmission schemes.

Detailed description of the invention:
In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example, in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the specific forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.
The terms "comprises", "comprising", "includes", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
In an embodiment, the closed-form expressions for the spectral efficiency over Nakagami-m fading channels under different adaptive transmission schemes with and without diversity combining.
In an aspect the present invention provides a method of spectral efficiency of selection combiner under Nakagamim fading channels comprising steps of:
a) evaluating the spectral efficiency without diversity for different fading conditions; and
b) evaluating the spectral efficiency using the simplest diversity combining method i.e., Selection Combining (SC), for different fading conditions.
In an embodiment, the comparative analysis has been done with dual and three-branch diversity under different fading conditions.
In an embodiment, the spectral efficiency is evaluated under optimum rate adaptation scheme being less complex.
In an embodiment, after optimum rate adaptation an optimum simultaneous power and rate adaptation (OPRA) is used for spectral analysis.
In an embodiment, after OPRA adaptation scheme a Channel inversion with fixed rate (CIFR) is used for spectral analysis.
In the present invention, the adaptive transmission schemes commonly used are ORA, OPRA, and CIFR. Under ORA scheme, the transmitted power is kept constant and as per the fading conditions in the channel data rate is adapted by the transmitter. Under OPRA scheme, both power and data rate are adapted by the transmitter as per the fading conditions in the channel. In CIFR scheme, in order to invert the channel into additive white Gaussian noise (AWGN) the transmitter adapts the channel power to manage constant SNR.
Diversity combining methods with the adaptive transmission schemes are earning a lot of consideration as being the assuring techniques to gain high channel capacity in the wireless mobile environment. The main objective with adaptive transmission schemes is to utilize channel state information (CSI) at receiver or at transmitter in order to enhance the channel capacity and lower the probability of outage.
Average channel capacity for dual branch SC diversity schemes over Nakagami-0.5 fading channels has been evaluated. Also, the numerical results of channel capacity for two different transmission schemes are compared with and without diversity combining. In using OPRA scheme, the average channel capacity using uncorrelated dual-branch MRC under Nakagami-0.5 fading distribution has been derived and results are compared with and without diversity combining. In, spectral efficiency is evaluated for dual branch SC under ORA and CIFR transmission schemes for the worst case of fading. However, considering the practical scenario all diversity branches have different amount of fading which leads to different fading parameters for different diversity branches. Therefore, the gap of evaluating the spectral efficiency for the practical SC containing different amount of fading in different diversity branches is filled here. Also, analytical and comparative analysis for the spectral efficiency for same fading conditions in all diversity branches as well as different fading conditions in different branches under different adaptation schemes is presented here.
The probability distribution function (PDF) of instantaneous received SNR, c in case of no diversity is given in as


The fading parameter is inversely proportional to the amount of fading and hence as the value of 'm' increases, amount of fading decreases and fading gets improved.
In the present invention, for the dual-branch diversity we have taken the case in which one of the branches is having the worst fading condition and the other branch is having the Rayleigh fading condition.
The Cumulative Distribution Function (CDF) for worst fading condition is given in as

As both the branches are statistically independent to each other so the combined CDF of the SC will be the product of CDFs of the two branches (2), (3) given by

The PDF of the SC can be obtained by differentiating the CDF with respect to the instantaneous SNR, So, the PDF of the SC in case of dual-branch diversity will be





, Claims:We Claim:
1. A method of spectral efficiency of selection combiner under Nakagamim fading channels comprising steps of:
a) evaluating the spectral efficiency without diversity for different fading conditions; and
b) evaluating the spectral efficiency using the simplest diversity combining method i.e., Selection Combining (SC), for different fading conditions.
2. The method of spectral efficiency of selection combiner under Nakagamim fading channels as claimed in claim 1, wherein the comparative analysis has been done with dual and three-branch diversity under different fading conditions.
3. The method of spectral efficiency of selection combiner under Nakagamim fading channels as claimed in claim 1, wherein the spectral efficiency is evaluated under optimum rate adaptation scheme being less complex.
4. The method of spectral efficiency of selection combiner under Nakagamim fading channels as claimed in claim 1, wherein the after optimum rate adaptation an optimum simultaneous power and rate adaptation (OPRA) is used for spectral analysis.
5. The method of spectral efficiency of selection combiner under Nakagamim fading channels as claimed in claim 1, wherein the after OPRA adaptation scheme a Channel inversion with fixed rate (CIFR) is used for spectral analysis.

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