Interference Rejection

The bit error rate (BER) performance of the asynchronous uplink channel of multicarrier code division multiple access (MC-CDMA) systems with maximal ratio combining (MRC) is analyzed. The study takes into account the effects of channel path correlations in generalized frequency-selective fading channels. Closed-form BER expressions are developed for correlated Nakagami fading channels with arbitrary fading parameters. For channels with correlated Rician fading paths, the BER formula developed is in one-dimensional integration form with finite integration limits, which is also easy to evaluate. The accuracy of the derived BER formulas are verified by computer simulations. The derived BER formulas are also useful in terms of computing other system performance measures such as error floor and user capacity.

A linear receiver for direct-sequence spreadspectrum multiple-access communication systems under the aperiodic random sequence model is considered. The receiver consists of the conventional matched filter followed by a tapped delay line with the provision of incorporating the use of antenna arrays. It has the ability of suppressing multipleaccess interference (MAI) and narrowband interference in some weighted proportions, as well as combining multipath components without explicit estimation of any channel conditions. Under some specific simplified channel models, the receiver reduces to the minimum variance distortionless response beamformer, the RAKE receiver, a notch filter, or an MAI suppressor. The interference rejection capability is made possible through a suitable choice of weights in the tapped delay line. The optimal weights can be obtained by straightforward but computationally complex eigenanalysis. In order to reduce the computational complexity, a simple blind adaptive algorithm is also developed.

This paper presents the subtraction method for interference cancellation in ECG. In contrast to the well-known hardware and software filters, the method does not affect the signal frequency components around the rated powerline frequency. The method searches for linear segments in the ECG signal. Then a digital filter is used to remove the interference from these segments. The samples of the interference signal are computed in these segments and later on these samples are used to remove by subtraction the interference from the signal where non-linear segments are encountered. A theoretical generalised approach of the method is developed in the paper.

Recently, several linear receiver algorithms have been developed for space-time block-coded multiaccess multiple-input multiple-output (MIMO) wireless communication systems. All these techniques are based on the assumption that the channel state information (CSI) at the receiver side is perfect. However, in practical situations, the available CSI may be imperfect because of channel estimation errors and/or outdated training. In this paper, we develop new robust linear receiver techniques for joint space-time decoding and interference rejection in multiaccess MIMO systems that use orthogonal space-time block codes and erroneous CSI. The proposed receivers are based on worstcase performance optimization. They are shown to provide a substantially improved robustness against CSI mismatches as compared with the existing linear multiaccess MIMO receivers.

This paper presents two new time-frequency distributions (TFDs) based on kernels with compact support (KCS) namely the separable (CB) (SCB) and the polynomial CB (PCB) TFDs. The implementation of this family of TFDs follows the method developed for the Cheriet-Belouchrani (CB) TFD. The mathematical properties of these three TFDs are analyzed and their performance is compared to the best classical quadratic TFDs using several tests on multicomponent signals with linear and nonlinear frequency modulation (FM) components including the noise effects. Instead of relying solely on visual inspection of the time-frequency domain plots, comparisons include the time slices' plots and the evaluation of the Boashash-Sucic's normalized instantaneous resolution performance measure that permits to provide the optimized TFD using a specific methodology. In all presented examples, the KCS-TFDs show a significant interference rejection, with the component energy concentration around their respective instantaneous frequency laws yielding high resolution measure values.

Reconfigurable computing play a vital role in this modern world of computer and electronics engineering,it allows to execute different application on the same hardware.Partial reconfiguration dynamically modify hardware portion of the device just by downloading configuration bit files.This results in increase in speed and functionality of FPGA based system.This paper presents flow of partial reconfiguration and implementation of reconfigurable modules using Planahead software on Xilinx virtex-5(XC5VLX50).Planahead software specifically design for partial reconfiguration as it has advance floorplanning capabilities.In order to verify the functionality, reconfigurable modules are designed and simulated using simulation tool on Xilinx 13.1 (ISE).

We report on the development of an accelerator mass spectrometry (AMS) system for the measurement of actinides at Lawrence Livermore National Laboratory. This AMS system is centered on a recently completed heavy isotope beam line that was designed particularly for high sensitivity, robust, high-throughput measurements of actinide concentrations and isotopic ratios. A fast isotope switching capability has been incorporated in the system, allowing flexibility in isotope selection and for the quasi-continuous normalization to a reference isotope spike. Initially, our utilization of the heavy isotope system has concentrated on the measurement of Pu isotopes. Under current operating conditions, background levels equivalent to ~1 X 10 5 atoms are observed during routine 239 Pu and 240 Pu measurements. Measurements of samples containing ~10 13 238 U atoms demonstrate that the system provides a 238 U rejection factor during 239 Pu measurements of ~10 7 . Measurements of known materials, combined with results from an externally organized inter-comparison program, indicate that our 239 Pu measurements are accurate and precise down to the µBq level (~10 6 atoms). Recently, we have investigated the performance of our heavy isotope AMS system in measurements of 237 Np and 236 U. Results of these investigations are discussed. The sensitivity shown by our Pu measurements, combined with the high throughput and interference rejection capabilities of our AMS system, demonstrate that AMS can provide a rapid and cost-effective measurement technique for actinides in a wide variety of studies.

In this paper a new expression of the signal to noise ratio (SNR) for Group orthogonal Code Division Multiple access (GO-CDMA) in frequency selective fading is derived and investigated. The SNR performance for frequency selective fading channel is shown by computer simulation The wireless industry is currently undergoing a major transition from second generation (2G) to third generation (3G) wireless technologies and the increasing demands for communication services require higher transmission rates that further stimulates the demand on wideband technologies depicted in the form of code division multiple access (CDMA) on one hand. Also, as the privacy is a prime issue in modern communications then the carriers orthogonality is a fundamental concept for a sustainable development of the communications sector. This paper attempts to assess wireless communications channels and propose N strategic perspective, an analytical study into the performance of Group Orthogonal Multi Carrier Code Division Multiple Access (GO-MC-CDMA) in which sub carriers assigned to users which are orthogonal to other groups, the channel bandwidth is the main theme of this paper; from which the problems that may affect the communications link are high lighted and measures to counterbalance and alleviate multi path fading are proposed and investigated. Such measures are: Space diversity combining techniques and minimum -mean square error and interference cancellation and detection are considered in this research.

synthetic thinned array radiometer (STAR) is described. The total power architecture of a radiometer receiver requires special considerations to control gain fluctuations due to small temperature drifts. The STAR application requires consistent passband and stable phase between receivers. The design presented incorporates direct detection to eliminate distributed local oscillators for phase stability, distributed ceramic interference reject filters for passband consistency and temperature compensating attenuators for gain stability. The receiver is packaged in a unique "winged-hex" shape to enable close packaging with the STAR antennas and to facilitate thermal management. The resulting low cost, compact receiver is made from COTS components.

Requirements for patient safety and a high interference rejection ratio in medical equipment create a demand for effective isolation devices. A system scale approach that uses capacitive coupling for power and signal isolation is presented. In addition, we describe the development of an instrumentation system prototype that applies microwaves for power exchange and bidirectional data transfer across the isolation barrier. The system consists of an isolated transducer unit, a central unit, and a single coaxial cable between the units. The isolation capacitance is as low as 1.6 pF, inclusive of the digital data transfer and power exchange up to 600 mW of isolated direct current (dc) power. The system is suitable for line-powered biopotential measurements and it is shown that reducing the isolation capacitance from 180 to 1.6 pF improves the power line rejection by 30 dB in a typical electrocardiogram (ECG) measurement setup.

In this paper we consider a specific case-study where M indoor femtocells share the same radio resources for communicating to the central office. An outdoor macro-cell base station increases the level of co-channel interference (cross-tier interference). Analysis of the co-tier (arising from neighboring femtocells) and cross-tier interference levels affecting the multifemtocell communications is based on a site-specific multi-link channel model obtained from a radio measurement campaign carried out at 2.4GHz [3]. In this context, we investigate the benefits of the Wireless over Cable (FemtoWoC) paradigm, based on the concept of deferring the PHY/MAC functionalities to a remote multicell FAP (femtocell access point), while leaving to the in-home device only the analog RF processing (amplifyand-forward-AF). Based on site-specific indoor-to-indoor and outdoor-to-indoor propagation parameters, interference mitigation for the uplink is carried out at the remote multicell FAP by taking into account realistic settings where: i) indoor radio propagation is impaired by Rician fading due to static multi-path fading components; ii) communication over the cable is affected by crosstalk produced by alien xDSL services; iii) imperfect knowledge of the radio channel limits the interference rejection performance at the multicell FAP.

A Smart Ultra-wideband (UWB) system using analog space time coding (STC) and adaptive GA (Genetic Algorithm) Rake receiver was previously introduced [ I]. The smart UWB system showed a great enhancement in performance over the SISO (single input single output) UWB one in a peer to peer scenario. In this paper the smart UWB system is used with the TR (Time Reversal) to enhance the performance of the smart UWB system in addition to reducing the receiver complexity. This paper also shows that using TR technique with the smart UWB system helps combating interferences from other UWB systems. Due to the dense resolved multipath components in UWB system, TR technique helps concentrating most of the energy of the desired signal at certain instance or path delay while that of interferers is spread over the multipath components. Thus, the desired signal energy at the receiver is dominant over the interfering ones. Finally, the smart UWB system uses the GA Rake to adaptively select the path delay at which the desired signal energy is maximized.

We demonstrate a signal-processing concept for imaging the sky at millisecond rates with radio interferometers. The "Pocket Correlator" (PoCo) correlates the signals from multiple elements of a radio interferometer fast enough to image brief, dispersed pulses. By the nature of interferometry, a millisecond correlator functions like a large, single-dish telescope, but with improved survey speed, spatial localization, calibration, and interference rejection. To test the concept, we installed PoCo at the Allen Telescope Array (ATA) to search for dispersed pulses from the Crab pulsar, B0329+54, and M31 using total-power, visibility-based, and image-plane techniques. In 1.7 hr of observing, PoCo detected 191 giant pulses from the Crab pulsar brighter than a typical 5σ sensitivity limit of 60 Jy over pulse widths of 3 ms. Roughly 40% of pulses from pulsar B0329+54 were detected by using novel visibility-based techniques. Observations of M31 constrain the rate of pulses brighter than 190 Jy in a three-degree region surrounding the galaxy to <4.3 hr −1. We calculate the computational demand of various visibility-based pulse search algorithms and demonstrate how compute clusters can help meet this demand. Larger implementations of the fast imaging concept will conduct blind searches for millisecond pulses in our Galaxy and beyond, providing a valuable probe of the interstellar/intergalactic media, discovering new kinds of radio transients, and localizing them to constrain models of their origin.

The problem of robust beamformer design in the presence of moving sources is considered. A new technique based on a generalization of the constrained minimum variance beamformer is proposed. The method explicitly takes into account c hanges in the scenario due to the movement of the desired and interfering sources, requiring only estimation of the desired DOA. Computer simulations show that the resulting performance constitutes a compromise between interference and noise rejection, computational complexity, and sensitivity to source movement.

synthetic thinned array radiometer (STAR) is described. The total power architecture of a radiometer receiver requires special considerations to control gain fluctuations due to small temperature drifts. The STAR application requires consistent passband and stable phase between receivers. The design presented incorporates direct detection to eliminate distributed local oscillators for phase stability, distributed ceramic interference reject filters for passband consistency and temperature compensating attenuators for gain stability. The receiver is packaged in a unique "winged-hex" shape to enable close packaging with the STAR antennas and to facilitate thermal management. The resulting low cost, compact receiver is made from COTS components.

In this proposed work we analyze the performance of different type of pulse shaping filters on the performance of DS-CDMA System using spreading sequences. We evaluate and compare the BER performance value of different type of pulses on multiuser detection. Our work will justify the best pulse shape on reducing the error in DS-CDMA system with the simulation results..

We have examined the convergence behavior of the LSCMA in some simple environments. Algorithms such as Multi¬ Target CMA, Multistage CMA, and Iterative Least Squares with Projection can be used for this purpose. The results presented here can form a basis for analysis of these multi-signal extraction techniques. Clearly, the variance and distribution of output SINR obtained with the LSCMA is also an important area for investigation. We finally comment on the hard-limit non-linearity. For high SIR, the hard-limiter is the optimal non-linearity when the desired signal has a constant envelope. However, at low SIR other non-linearities can yield greater SIR gain. Thus, it is possible that non-linear functions other than the hard-limit can be used to develop blind adaptive algorithms, which converge faster for low initial SINR.

where the sequence d (n) ~{-l , 1} represents the This paper is dedicated to an experimental validation of an improved analytic expression of bit error rate (BER) previously given by C. Negrescu and D. Stanomir in [6]. The results of the simulation will be compared with classic expression [2],[3]. The new improved formula predicts the BER with a significant higher degree of accuracy.

environments. Intense background noise, however, often corrupts speech and degrades the performance of many communication systems. Thus a large variety of noise reduction techniques have been proposed for reducing background noise in noisy environment, see (Narendra and Han 2012; Moir and Harris 2012; Niedźwiecki and Meller 2012; Roshahliza 2017; Jayakumar et al. 2016) and references therein. The recent noise reduction techniques prefer multi-microphone systems (Bitzer et al. 2001; Mohammed 2009; Touazi and Debyeche 2017), over singlemicrophone systems (Boll 1979; Sasaoka et al. 2005) due to the obvious advantages provided by the former over the later. A multi-microphone system can be considered as a directional microphone with a zero response (null) in the noise direction. However, the microphone array involves increased cost in the form of more microphones, D/A converters, memory, signal processing power, etc. On the other hand, spectral subtraction method (Boll 1979) is known to use single-microphone system. However, in the spectral subtraction method, the musical tones arise from residual noise and it requires the speech/non-speech section detector under the noisy environments. The widely used adaptive noise canceller (Widrow et al. 1975) consists a single stage with two microphones namely, the primary microphone which is placed close to the signal source to pick up the desired signal and the reference microphone which is placed close to the noise source to sense only the noise. Also it employs an adaptive filter with the LMS algorithm to cancel the noise component embedded in the primary signal. The adaptive filter has the task of modeling the impulse response path between noise source and primary microphone. In real-time environment, the background noise typically comes from various sources such as ventilating fan, audio equipment, engines etc. Therefore, the background noise maybe consists of wideband noise as well

Multi-cellular radio systems are often limited due to the presence of cochannel interference. Physical layer concepts as e.g. interference rejection combining, optimize the receiver side and thus strengthen the signal while combating the interference at the terminal side only. It is well known that joint transceiver optimization, i.e. coordinated joint transmission from several base stations, yields large capacity improvement for downlink transmission. However, the performance highly depends on the available channel knowledge. We focus on how to realize a decentralized and limited cooperative downlink transmission in a multi-cellular network. This yields the crucial question: Is an efficient cooperative transmission possible by using simple channel quality identifiers, or is channel state information at the transmitter mandatory? Further, we use minimum mean square error equalization at the terminal side to combat residual cochannel interference. For baseline we apply receiver optimization only and compare these results with those obtained from cooperative transmission. We demonstrate potential capacity gains in a cellular orthogonal frequency division multiplexing system and their scaling with the number of cooperating antenna arrays.

Multicellular radio systems are often limited due to the presence of cochannel interference. Proposed physical layer concepts, e.g. coordinated joint transmission and interference rejection combining, try to strengthen the signal while combating the interference. However, the performance may be limited by the available channel knowledge. We provide a concept for multi-cell channel estimation in the downlink applicable for for both physical layer concepts. This concept uses virtual pilots based on block-orthogonal sequences, e.g. Hadamard.

Empirical mode decomposition (EMD) is a tool developed for analyzing nonlinear and nonstationary signals. It is capable of splitting any signal into a set of oscillation modes known as intrinsic mode functions and a residual function. Although the EMD satisfies the perfect signal reconstruction property by superimposing all the oscillation modes, it is not based on any optimality criterion. The lack of optimality limits the signal recovery performance of the EMD in the presence of disturbances such as noise and interference. In this paper, we propose a new algorithm, termed, time-varying weighted EMD, which gives the best estimate of a given signal in the minimum mean-square error sense. The main idea of the proposed algorithm is to reconstruct the original signal through the EMD followed by timevarying weightings of the oscillation modes. Simulations including two real-life signals are performed to show the superiority of the proposed algorithm.

Radar scanenng from the ocean surface', IEE Pmc. E 1990, 137, (2), pp. 5 1 4 2 a-5 DAVIDSON, G.: 'Doppler filtering and detection strategies for multifunction Radar Ph.D., Thesisp. 25116 University o f London (hap:llwww.ee.ucl.ac.uW-gdavid) RUNGALDER, H., and SHELTON, I: 'Power spectral lineshapes of miemwave radiation backscattered from sea surfaces at small grazing 6

The rejection of QPSK interference in a THPPM UWB system using complex adaptive filter and a nonlinear correlation receiver (NCR) with a soft-limiter will be considered in this paper. This system brings a significant performance improvement compared to the system which uses complex adaptive filter and a linear receiver, particularly in the case of high interference power, where its absence leads to the reception loss.

In this paper we proposed a smart interference rejection filter in TH-PPM UWB system, which improves the system's error probability for an order of magnitude in case of high power OFDM interference. The smart filter is based on an adaptive transversal filter. Based on the fulfillment of certain conditions, the filter activates or deactivates some parts of it.

Radar scanenng from the ocean surface', IEE Pmc. E 1990, 137, (2), pp. 5 1 4 2 a-5 DAVIDSON, G.: 'Doppler filtering and detection strategies for multifunction Radar Ph.D., Thesisp. 25116 University o f London (hap:llwww.ee.ucl.ac.uW-gdavid) RUNGALDER, H., and SHELTON, I: 'Power spectral lineshapes of miemwave radiation backscattered from sea surfaces at small grazing 6

PSK interference rejection using complex adaptive filter with conditional response recalculation in DS-SS/PSK system is considered in this paper. New adaptive filter decreases error probability for several orders of magnitude when compared to the standard adaptive transversal filter.

Multiple noise sources in a realistic environment severely degrade the quality and intelligibility of the desired speech signal, thus posing a severe problem for many speech applications. Several noise reduction algorithms have been proposed with a main goal to solve this problem. However, the good performances of such algorithms are severely impaired in realistic environment under multi-noise sources condition. In this paper, the author treats the noise cancellation system as a multipleinput multiple-output (MIMO) beamformer system. The proposed approach consists of two steps. First, the noise signals are generated by applying the white noise sources to a MIMO AR system. Then, the noisy microphone signals are sequentially processed by employing multi-channel linear prediction error filters (MCLPEFs) and multi-channel adaptive noise estimation filters (MCANEFs) in the lower path of the proposed beamformer. The MCLPEFs are used to whiten the input signals, while the MCANEFs are used as a MIMO system identification to perform the modeling process of the noise signals. Finally, the noise signals in the upper path are subtracted from the estimated noises in the lower path to recover an enhanced speech signal. Moreover, the performance of the proposed MIMO approach was validated under a realistic environment with real noise sources.

Delay-and-Sum (DAS) is the most common algorithm used in photoacoustic (PA) image formation. However, this algorithm results in a reconstructed image with a wide mainlobe and high level of sidelobes. Minimum variance (MV), as an adaptive beamformer, overcomes these limitations and improves the image resolution and contrast. In this paper, a novel algorithm, named modified-sparse-MV (MS-MV) is proposed in which a 1-norm constraint is added to the MV minimization problem after some modifications, in order to suppress the sidelobes more efficiently, compared to MV. The added constraint can be interpreted as the sparsity of the output of the MV beamformed signals. Since the final minimization problem is convex, it can be solved efficiently using a simple iterative algorithm. The numerical results show that the proposed method, MS-MV beamformer, improves the signal-to-noise (SN R) about 19.48 dB, in average, compared to MV. Also, the experimental results, using a wire-target phantom, show that MS-MV leads to SN R improvement of about 2.64 dB in comparison with the MV.

A Smart Ultra-wideband (UWB) system using analog space time coding (STC) and adaptive GA (Genetic Algorithm) Rake receiver was previously introduced [ I]. The smart UWB system showed a great enhancement in performance over the SISO (single input single output) UWB one in a peer to peer scenario. In this paper the smart UWB system is used with the TR (Time Reversal) to enhance the performance of the smart UWB system in addition to reducing the receiver complexity. This paper also shows that using TR technique with the smart UWB system helps combating interferences from other UWB systems. Due to the dense resolved multipath components in UWB system, TR technique helps concentrating most of the energy of the desired signal at certain instance or path delay while that of interferers is spread over the multipath components. Thus, the desired signal energy at the receiver is dominant over the interfering ones. Finally, the smart UWB system uses the GA Rake to adaptively select the path delay at which the desired signal energy is maximized.

A Smart Ultra-wideband (UWB) system using analog space time coding (STC) and adaptive GA (Genetic Algorithm) Rake receiver was previously introduced [ I]. The smart UWB system showed a great enhancement in performance over the SISO (single input single output) UWB one in a peer to peer scenario. In this paper the smart UWB system is used with the TR (Time Reversal) to enhance the performance of the smart UWB system in addition to reducing the receiver complexity. This paper also shows that using TR technique with the smart UWB system helps combating interferences from other UWB systems. Due to the dense resolved multipath components in UWB system, TR technique helps concentrating most of the energy of the desired signal at certain instance or path delay while that of interferers is spread over the multipath components. Thus, the desired signal energy at the receiver is dominant over the interfering ones. Finally, the smart UWB system uses the GA Rake to adaptively select the path delay at which the desired signal energy is maximized.

he growth in wireless communications necessitates more efficient utilization of spectrum. The increased sharing of spectrum translates into a higher likelihood of users interfering with one another. Interferencerejection techniques allow a high capacity of users within available spectrum This overview comprises a literature review of published papers pertianing to single-channel adaptive interence rejection in digital wireless dating primarily from 1980 to the present. Though previous overviews are referenced and summarized, the focus is on advances not covered by previous overviews (consequently, some papers are included that predate 1980 because they are not covered in previous overviews). The organizational chart shown in Fig. 1 outlines the types of techniques covered by this article. For the benefit of the nonspecialist, tutorial material begins most sections to introduce each category. Following the tutorial material, each section contains a summary of recent advances and contributions to the particular area. For cursory reading, one can focus on the first few paragraphs to gain insight into the general technique and skip the subsequent summary of particular contributions. To assist in the reading of the material, Table 1 furnishes a list of abbreviations used throughout this article.

In this paper, we develop a sparse model to represent the data recorded by a polarimetric, coherent radar. We produce this model defining an over-complete library of possible target responses in the range-polarization space. Then, we employ compressive sensing methods to infer the position and the scattering matrix of the target. Using real radar data, we show that this new approach offers better interference rejection over other methods.

In this paper, we develop a sparse model to represent the data recorded by a polarimetric, coherent radar. We produce this model defining an over-complete library of possible target responses in the range-polarization space. Then, we employ compressive sensing methods to infer the position and the scattering matrix of the target. Using real radar data, we show that this new approach offers better interference rejection over other methods.

Microwave-induced thermal acoustic imaging (TAI) is a promising early breast cancer detection technique, which combines the advantages of microwave stimulation and ultrasound imaging and offers a high imaging contrast, as well as high spatial resolution at the same time. A new multifrequency microwave-induced thermal acoustic imaging scheme for early breast cancer detection is proposed in this paper. Significantly more information about the human breast can be gathered using multiple frequency microwave stimulation. A multifrequency adaptive and robust technique (MART) is presented for image formation. Due to its data-adaptive nature, MART can achieve better resolution and better interference rejection capability than its data-independent counterparts, such as the delay-and-sum method. The effectiveness of this procedure is shown by several numerical examples based on 2-D breast models. The finite-difference time-domain method is used to simulate the electromagnetic field distribution, the absorbed microwave energy density, and the thermal acoustic field in the breast model. Index Terms-Breast cancer detection, finite-difference time-domain (FDTD) methods, multifrequency adaptive and robust technology (MART), robust capon beamforming (RCB), thermal acoustic imaging (TAI).

The overlapped equal subarray transmit radar, which is also known as the Subarray Multiple-Input Multiple-Output radar, utilizes the key advantages simultaneously of both types of multi-antenna radar, i.e. the phased array and MIMO radars, so that it is able to detect multiple targets even though it has a radar cross section (RCS) of a weak or small target. In this paper, it is proposed to develop a parameter estimation approach called amplitude and phase estimation (APES). This approach provides improved resolution to the estimation of the amplitude and direction of arrival (DoA) of the target reflection signal on the radar compared to the existing conventional estimation methods such as least squares (LS). The formulation of the APES method on this radar is based on the tested parameters such as DoA and RCS and continuously being evaluated. The results show that the performance of the APES method of this radar can detect targets very precisely when the number of subarrays (M) is g...

A new sidelobe canceller (SLC) using the signal subspace eigenvectors of the incident signal covariance matrix is proposed. Assuming independent point signal sources, it is analytically shown that the proposed SLC method produces exact nulls at the direction of interferences and thereby completely rejects the interference. Robustness of the proposed method is evaluated using computer simulations.

Abstract—Wireless network deployments are becoming in-creasingly complex in order to cope with the exponential growth in mobile data traffic. Multi-tier technologies capable of supporting spatially dense networks enable high data rates, but require timely and accurate models of the radio environment, particularly for scenarios that incorporate dynamic access to spectrum. However, network planners, algorithm designers, and policy makers are often forced to rely on a small set of radio propagation scenarios, often assuming fixed receiver antenna heights (RAHs). In this paper we show that the RAH in fact plays a key role not only in terms of reception quality but also in determining the interference originating from other transmitters. Our extensive simulation studies show a large variability in key performance metrics of realistic wireless network topologies as RAH is varied, which are not captured through the current practice of selecting few effectively two-dimensional scenarios and...

Wireless network deployments are becoming increasingly complex in order to cope with the exponential growth in mobile data traffic. Multi-tier technologies capable of supporting spatially dense networks enable high data rates, but require timely and accurate models of the radio environment, particularly for scenarios that incorporate dynamic access to spectrum. However, network planners, algorithm designers, and policy makers are often forced to rely on a small set of radio propagation scenarios, often assuming fixed receiver antenna heights (RAHs). In this paper we show that the RAH in fact plays a key role not only in terms of reception quality but also in determining the interference originating from other transmitters. Our extensive simulation studies show a large variability in key performance metrics of realistic wireless network topologies as RAH is varied, which are not captured through the current practice of selecting few effectively twodimensional scenarios and drawing general conclusions from them. These results underline the importance of adopting more realistic assumptions on RAH for design, assessment, and policy making for wireless communication systems, and the need for new propagation models valid for a wider range of RAH values than models currently in use.