Co-channel Interference Probability Research Articles

Estimation Based on Chirp Modulation for Desired and Interference Power and Channel Occupancy Ratio in LoRa.

In terms of low power consumption and long-range communication—low-power wide-area networks (LPWAN) are suitable for wireless sensor networks. Long-range (LoRa) wireless communication is one of the standards of LPWAN. LoRa shares common frequency spectrum bands with both multiple transmitters, which are the sensors in the LoRa system (and those in the other system). Therefore, co-channel interference (CCI) degrades the packet delivery rate. To avoid CCI, the CCI power and the occurrence probability of CCI in the target channel are estimated, then the sensor decides whether to use the channel and where the occurrence probability of CCI is defined as the channel occupancy ratio (COR). If a large signal power is obtained at the receiver, the received signal can be demodulated because of the capture effect. The desired signal power must also be estimated for the capture effect. In this study, we propose an estimation scheme based on chirp modulation of LoRa under spectrum sharing among other systems. The proposed scheme estimates the desired signal power, CCI power, and COR. From the computer simulation results, we clarify the advantages of the proposed scheme in terms of estimation accuracy and packet delivery rate.

A Framework for Co-Channel Interference and Collision Probability Tradeoff in LTE Licensed-Assisted Access Networks

Small cell deployment in heterogeneous networks, whereby small cell base stations (SBS) are deployed alongside traditional macro-cell base stations, is a proven solution for enhancing spatial frequency reuse across licensed spectrum in long-term evolution (LTE) networks. In order to mitigate the shortage of licensed spectrum resources, licensed-assisted access (LAA) has been introduced to allow LTE SBSs to share the unlicensed channel with WiFi nodes. As such, a complex yet interesting optimization problem results from the joint utilization of licensed and unlicensed spectrum resources by the SBSs to meet the quality-of-service (QoS) requirements of small cell users (SUEs). In this paper, we highlight the fundamental tradeoff induced by the SBSs between the amount of co-channel interference (CI) resulting from the reuse of licensed spectrum resources and the collision probability (CP) imposed on the co-existing WiFi nodes due to the sharing of unlicensed spectrum resources in such a coexisting LTE LAA-WiFi heterogeneous network deployment. We find that this fundamental tradeoff can be analyzed by developing a power allocation rule with double water-filling lines and the complete set of Pareto optimal solution can be achieved by the weighted Tchebycheff method. Our simulation results show that the proposed joint resource allocation algorithm can achieve a flexible and suitable tradeoff between the licensed spectrum CI and the WiFi CP according to the QoS requirements of SUEs in LTE LAA networks.

IAPS: Interference Aware Power Saving for High-Efficiency Wireless LANs in Dense Networks

Battery-driven circuit design for power saving wireless local area networks (WLANs) has become more and more important because mobile devices and applications are required to support high throughput in wide service coverage and, at the same time, exhibit long battery lifetime. However, in dense networks, multiple and dynamic channel access leads to a higher probability of co-channel and adjacent channel interference. Therefore, the energy efficiency of IEEE 802.11-based WLANs is severely degraded by such interference. In this letter, an interference-aware power saving (IAPS) mechanism is proposed. The IAPS incorporates a signal quality and interference measurement process for determining link quality based on the incoming signal from a receiver. In the IAPS, the signal field decoding process is used to determine the required link quality for the received signal, and a physical layer power saving control based on the estimated link quality and the required link quality is implemented. The proposed IAPS technique achieves 29% and 26% average energy efficiency improvement over the conventional scheme and the channel hopping scheme, respectively.

Analysis on Characteristics for Sharing Co-channel between Communication Systems

In this paper, we analyze the distance between two systems, WiBro and WLAN, compared to standard interference probability for channel co-use in order to be used as a criteria in realization. Co-channel and adjacent channel interference probability and its effect of (WiBro) into Wireless LAN (WLAN) in TV White Spaces (TVWS) is evaluated through Spectrum Engineering Advanced Monte Carlo Analysis Tool(SEAMCAT) based on the Monte-Carlo simulation method. As a result, in the case of co-channel interference, the minimum distance between WiBro Mobile Station(MS) and WLAN User Equipment (UE) should be 210 m to allow the maximum transmitter power of WiBro UE of 25 dBm. The transmit power of WiBro BS have to be reduced to -4.96 dBm.

On the development of fully adaptive channel allocation strategies for usage in high‐capacity cellular mobile radio systems

AbstractAn alternative mathematical expression for the co‐channel interference probability is used, in order to calculate the cellular mobile radio system capacity and to construct a set of compatibility constraints needed for the development of fully adaptive channel allocation (FACA) strategies. The development of such channel allocation techniques becomes a main thrust for the system engineers in order to design an efficient system to manage traffic demands over the service area of a third generation cellular system. Three proposed FACA strategies are analysed and a simulation model is developed, in order to examine the performance of these strategies. Copyright © 2001 John Wiley & Sons, Ltd.

Effects of CIR selection diversity with two correlated branches in the m-fading channel

A number of methods for the measurement of channel impulse response (CIR) (desired signal carrier power to interference ratio) have been proposed in cellular mobile radio systems. The paper estimates the probability of cochannel interference for CIR selection diversity having two correlated branches in the m-fading channel. The advantage of CIR selection diversity over selection diversity based on the desired signal power algorithm is confirmed.

Effects of Rician fading and branch correlation on a local-mean-based macrodiversity cellular system

In a macrodiversity cellular system, switching radio links between base stations cannot be done instantaneously. Thus, branch selection is usually based on the measurement of the slowly varying local-mean power rather than the rapidly varying instantaneous signal power. We offer an exact mathematical model to analyze the performance of a local-mean-based macrodiversity cellular system in a shadowed-Rician (desired)/shadowed-Rayleigh (interfering) channel. We investigate the impact of both fading (Rician or Rayleigh) and shadowing in terms of cochannel interference (CCI) probability. We also present an analytical model to incorporate the effects of branch correlation on macrodiversity systems.

Effect of branch correlation on a macrodiversity system in a shadowed Rician fading channel

The authors present an exact analysis of the co-channel interference probability of a macrodiversity cellular system with an arbitrary number of correlated branches, where the branch selection is based on local mean power. Results show that the effects of macrodiversity branch correlation cannot be ignored in the performance analysis of microcell and picocellular systems.

Probability of cochannel interference in the case of noncoherent phasor addition with unequal powers in Rayleigh fading environments

New, closed form expressions are derived for calculation of the probability of cochannel interference (PCI) in Rayleigh fading environments when interfering phasors with unequal mean powers add noncoherently in the receiver. Expressions enable PCI calculation at every point within a cell and/or cluster, both in base stations and mobile units.

Incoherent estimation on co-channel interference probability for microcellular systems

Prasad and Kegel (1993) offered an approximate analysis of the co-channel interference (CCI) probability for a microcellular system that has multiple shadowed Rayleigh interfering signals and a shadowed Rician desired signal. In that analysis, coherent addition of summing multiple interfering signals was assumed. However, it has been shown that incoherent addition is a more realistic assumption (Prasad and Kegel 1991). In the present paper two approaches-approximation and exact analysis-for calculating the CCI probability under incoherent addition are given. The approximate analysis is extended from the macrocellular case. The exact analysis, newly developed in the present paper, is then used to check the accuracy of the approximation. It is shown that the results of the incoherent approximate analysis differ by an amount of 20/spl sim/30%. In addition, the authors explore the effect of correlation between the shadowing interferers. They find that in a shadowed-Rician/shadowed-Rayleigh channel, the effect of this kind of correlation increases the CCI probability for cases having a small spread in shadowing and large reuse distance. But if the spread in shadowing is large, the result can be just the opposite-this correlation yields a better performance. It is also found that in a shadowed-Rayleigh (desired)/shadowed-Rayleigh (interfering) channel, regardless of degree of spread in shadowing, this correlation seems always to improve the performance.

Correlated co‐channel log‐normal interferers in cellular radio

AbstractThe probability of co‐channel interference (PCI) in cellular radio systems is analyzed assuming that the desired signal and the co‐channel interferers are correlated in a log‐normal shadowing environment. The correlation between the signals in a log‐normal shadowing environment reduces the PCI and hence allows operation with shorter frequency reuse distances and smaller cluster sizes. Compared with omnidirectional systems, the cells employing directional antennas can operate with shorter frequency reuse distances and hence provide better usage of the frequency spectrum.

Exact cochannel interference analysis for log-normal shadowed Rician fading channels

An exact analytical method is presented for evaluating the probability of cochannel interference for Rician/Rayleigh faded channels with log-normal shadowing. The method requires that at least one signal (desired or interfering) be Rayleigh faded and log-normal shadowed. The Rice factor of the desired signal is shown to have a large effect on the probability of cochannel interference, while the Rice factors of the interfering signals are shown to have little effect.

Optimal channel reuse in cellular radio systems with multiple correlated log-normal interferers

The probability of co-channel interference (PCI) due to multiple correlated log-normal signals is calculated for cellular radio systems operating in Rayleigh fading and lognormal shadowing environment. The effects on the PCI of the correlation between the signals, the standard deviation due to shadowing, the number of interferers, the co-channel protection ratio, and the traffic load is investigated. The results are used for analyzing the optimal channel reuse, the cluster size, and the spectrum efficiency in terms of these parameters. >

Cochannel interference probability for micro and picocellular systems at 60 GHz

Cochannel interference probability is evaluated for micro- and picocellular systems considering the oxygen absorption at 60 GHz. For a picocellular system both desired and interfering signals are Rician distributed, whereas for a microcellular system the desired and interfering signals are Rician and Rayleigh distributed, respectively.

Effects of Rician faded and log-normal shadowed signals on spectrum efficiency in microcellular radio

An assessment of spectrum efficiency for a microcellular land mobile radio system is presented by considering the desired signal as (fast) Rician fading with (slow) log-normal shadowing and cochannel interfering signals as uncorrelated (fast) Rayleigh fading superimposed over (slow) log-normal shadowing. Spectrum efficiency is defined in terms of reuse distance, i.e., cluster size, traffic intensity, bandwidth of the system, and area of a cell by considering cochannel interference probability. The expression for cochannel interference probability is derived using appropriate path-loss law for microcells for four different cases: Rician plus log-normal desired signal and Rayleigh plus log-normal interfering signals; Rician desired signal and Rayleigh fading plus log-normal shadowing interfering signals; Rician desired signal and Rayleigh interfering signals; and both desired and interfering signals as Rician fading. The performance of a microcellular system is compared with that of a conventional macrocellular system. >

Erratum: Cochannel interference probability for picocellular systems with multiple Rician faded interferers

Erratum: Cochannel interference probability for picocellular systems with multiple Rician faded interferers

Multiple correlated log-normal interferers in mobile cellular radio systems

The probability of cochannel interference (PCI) is evaluated in shadowed mobile cellular systems considering multiple correlated log-normal interferers. The influence of blocking probability and the number of channels per cell on the performance is also presented. The effect of correlation on PCI is investigated for various values of the propagation path loss exponent.

Probability off co-channel interference for selection diversity reception in the nakagami m-fading channel

A recent second generation highcapacity mobile radio telephone system in Japan employs selection diversity with two branches on the mobile receiver to counteract co-channel interference from distant base stations operating with identical frequencies. From an actual point of view it seems more reasonable to assume that the fluctuations of signal carrier envelopes on the mobile receiver are approximated by the m-distribution proposed by Nakagami when we try to investigate fading statistics for land mobile radio not only in urban areas but in suburban or open areas. The m-distribution is a generalisation of the Rayleigh distribution and it can take account of the influence of a superimposed specular component other than scattered and reflected waves. The probability density function of the wanted signal envelope and its characteristic function for selection diversity in the m-fading channel are derived in conveniently closed form, and the probability of co-channel interference that the wanted signalcarrier to interference power ratio (CIR) is less than a specified protection ratio is calculated. The results obtained will serve to decide the modulation system employed and to estimate the frequency re-use distance, the number of channel groups, and the efficiency of spectrum use in cellular mobile radio.

Cochannel interference probability for picocellular system with multiple Rician faded interferers

The expression for cochannel interference probability is derived for a picocellular system considering Rician faded signals. The interference probability is evaluated as a function of reuse distance with path-loss exponent and traffic intensity as parameters for typical values of Rician factor, protection ratio and the number of channels per cell.

Effects of correlated shadowing signals on channel reuse in mobile radio systems

The authors present a study to evaluate the cochannel interference probability for the desired and interference signals which are correlated due to shadowing. The effects of correlation on the normalized reuse distance are investigated. A generalized expression for the cochannel interference probability is derived by combining uncorrelated (fast) Rayleigh fading and correlated (slow) log-normal signals. The cochannel interference probability for sectorized cell layouts is compared with the lower bound of cochannel interference probability for omnidirectional antenna systems. It is found that omnidirectional cell layouts cause the highest level of cochannel interference probability. An omnidirectional system requires a higher cluster size than a directional system to maintain acceptable cochannel interference.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>