Statistical Modeling of Cognitive Network Interference (original) (raw)
Related papers
Cognitive Network Interference
IEEE Journal on Selected Areas in Communications, 2000
Opportunistic spectrum access creates the opening of under-utilized portions of the licensed spectrum for reuse, provided that the transmissions of secondary radios do not cause harmful interference to primary users. Such a system would require secondary users to be cognitive-they must accurately detect and rapidly react to varying spectrum usage. Therefore, it is important to characterize the effect of cognitive network interference due to such secondary spectrum reuse. In this paper, we propose a new statistical model for aggregate interference of a cognitive network, which accounts for the sensing procedure, secondary spatial reuse protocol, and environment-dependent conditions such as path loss, shadowing, and channel fading. We first derive the characteristic function and cumulants of the cognitive network interference at a primary user. Using the theory of truncated-stable distributions, we then develop the statistical model for the cognitive network interference. We further extend this model to include the effect of power control and demonstrate the use of our model in evaluating the system performance of cognitive networks. Numerical results show the effectiveness of our model for capturing the statistical behavior of the cognitive network interference. This work provides essential understanding of interference for successful deployment of future cognitive networks.
Cognitive Network Interference- Modeling and Applications
2011 IEEE International Conference on Communications (ICC), 2011
Opportunistic spectrum access creates the opening of under-utilized portions of the licensed spectrum for reuse, provided that the transmissions of secondary radios do not cause harmful interference to primary users. Therefore, it is important to characterize the effect of cognitive network interference due to such secondary spectrum reuse. In this paper, we show how a new statistical model for aggregate interference of a cognitive network, which accounts for the sensing procedure, secondary spatial reuse protocol, and environment-dependent conditions such as path loss, shadowing, and channel fading can be used to assess the aggregate interference in specific environments. Specifically, we consider scenarios like power controlled primary network, secondary network with interference avoidance mechanism, and non-circular coverage region.
Interference Modeling of Cognitive Radio Networks
VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008
Cognitive radio (secondary) networks have been proposed as means to improve the spectrum utilization. A secondary network can reuse the spectrum of a primary network under the condition that the primary services are not harmfully interrupted. In this paper, we study the distribution of the interference power at a primary receiver when the interfering secondary terminals are distributed in a Poisson field. We assume that a secondary terminal is able to cease its transmission if it is within a distance of R to the primary receiver. We derive a general formula for the characteristic function of the random interference generated by such a secondary network. With this general formula we investigate the impacts of R, shadowing, and small scale fading on the probability density function (PDF) of the interference power. We find that when there is no interference region (R = 0), the interference PDFs follow heavy-tailed α-stable distributions. In case that a proper interference region is defined by a positive value of R, the tails of the interference power PDFs can be significantly shortened. Moreover, the impacts of shadowing and small scale fading on the interference PDFs are studied and the small scale fading is found to be beneficial in terms of reducing the mean value and outage probability of the interference power.
On distribution of aggregate interference in cognitive radio networks
2010 25th Biennial Symposium on Communications, 2010
This paper analyzes the distribution of aggregate interference in cognitive radio networks. Poisson point spatial distribution model and average propagation path loss model are considered. All possible scenarios are classified into three typical cases, based on typical outage events. When the average number of nodes in the forbidden region is much smaller than one, the aggregate interference can be well approximated by the nearest one (nearest node dominates outage events). When the average number of nodes in the forbidden range is greater than one, the aggregate interference can be approximated by a Gaussian random variable (many nodes contribute to outage). When the average number of nodes in the forbidden range is slightly smaller than one, neither the nearest node approximation nor Gaussian one is accurate (a few near-by nodes are dominant), and higher order cumulants approximations or others are required. We derive the nearest interference distribution and give a simpler way to calculate the cumulants of the aggregate interference. † Y. Wen, S. Loyka and A. Yongacoglu are with the
Interference in a Cognitive Network with Beacon
2008
We study a cognitive network consisting of multiple cognitive users communicating in the presence of a single primary user. The primary user is located at the center of the network, and the cognitive users are uniformly distributed within a circle around the primary user. Assuming a constant cognitive user density, the radius of this circle will increase with the number of users. We consider a scheme in which the primary transmitter sends a beacon signaling its own transmission. The cognitive users, upon receiving this beacon, stay silent. Because of channel fading, however, there is a non-zero probability that a cognitive user misses the beacon and hence, with a certain activity factor, transmits concurrently with the primary user. Given the location of the primary receiver, we are interested in the total interference caused by the cognitive users to this receiver. In particular, we provide closed-form bounds on the mean and variance of the interference, and relate them to the outage probability on the primary user. These analytical results can help in the design of a cognitive network with beacon.
IEEE Transactions on Signal Processing, 2000
In this paper we study the system level performance of cognitive radio (CR) networks under average received interference power constraints. Under the assumption of uniform node placements and a simple power control scheme, we derive the closed-form expression for the cumulative distribution function (CDF) of the maximum allowable transmit power of the target CR transmitter. We further study two CR network scenarios: a CR based central access network and a CR assisted virtual multiple-input multiple-output (MIMO) network. The average uplink capacities of both networks are derived and analyzed, with an emphasis on understanding the effect of the numbers of primary users and CR users on the capacity. Numerical and simulation results demonstrate that the CR based central access network is more suitable for less-populated rural areas where a lower density of primary receivers is expected, while the CR assisted virtual MIMO network performs better in urban environments with a dense population of mobile CR users.
Accumulative Interference Modeling for Distributed Cognitive Radio Networks
Journal of Communications, 2009
A Cognitive Radio (CR) network should be able to sense its environment to adapt its communication so that it can utilize unused licensed spectrum without interfering with incumbent users. Properly modeling the expected interference from the entire CR network is there- fore very important to effectively protect these incumbent users. We model the accumulative interference generated from a large-scale CR
Impact of Secondary User Interference on Primary Network in Cognitive Radio Systems
2018
Most of the research in cognitive radio field is primarily focused on finding and improving secondary user (SU) performance parameters such as bit error rate, outage probability and capacity etc. Less attention is being paid towards the other side of the network that is the primary network which is under interference from SU. Also, it is the primary user (PU) that decides upon the interference temperature constraint for power adaptation to maintain a certain level of quality of service while providing access to SUs. However, given the random nature of wireless communication, interference temperature can be regulated dynamically to overcome the bottlenecks in entire network performance. In order to do so, we need to analyze the primary network carefully. This study tries to fill this gap by analytically finding the closed form theoretical expressions for signal to interference and noise ratio (SINR), mean SINR, instantaneous capacity, mean capacity and outage probability of PU, while...
Impact of Interference from Primary User on the Performance of Cognitive Radio Networks
2012
This thesis report presents background knowledge about cognitive radio network (CRN) and investigates performance of underlay cognitive radio networks based on an adaptive power allocation policy of secondary transmitter (SU-Tx). In particular, it has been assumed that SU-Tx and primary user transmitter (PU-Tx) are equipped with a single antenna, while the corresponding receivers are equipped with multiple antennas. Additionally, SU-Tx operates under the joint constraint of its peak transmission power and outage constraint of the primary network. The probability density function (PDF) and cumulative density function (CDF) of the signal to interference and noise ratio (SINR) of SU over Rayleigh fading channel are derived. Using these two functions, a closed-form expression for the outage probability and an approximate expression for ergodic capacity of the considered system are obtained. Matlab simulation results are provided to validate the correctness of the analyses. The results s...
2010 IEEE 72nd Vehicular Technology Conference - Fall, 2010
This paper presents a study on interference caused by Secondary Users (SUs) due to miss-detection and its effects on the capacity-outage performance of the Primary User (PU) in a cognitive network for two scenarios of beacon transmitter placement: beacon transmitter located at PU transmitter or at PU receiver. Interference analysis shows that aggregate interference power from SUs has a Gamma distribution when beacon transmitter is located at PU receiver, while it can be approximated as a shifted-Gamma distributed random variable for the case of beacon transmitter located at PU transmitter. Based on statistical model for the interference distribution, closed-form expressions of the capacity-outage probability of the PU are developed to examine the effects of various system parameters on the performance of the PU in presence of interference from SUs. Simulation results confirm the validity of the developed analytical models. It is shown that beacon transmitter at PU receiver offers lower interference and hence better capacity-outage probability to the PU than beacon transmitter at PU transmitter. I.