Papers by Arvind Merwaday
Capacity analysis of LTE-Advanced HetNets with reduced power subframes and range expansion
EURASIP Journal on Wireless Communications and Networking, 2014
ABSTRACT The time domain inter-cell interference coordination techniques specified in LTE Rel. 10... more ABSTRACT The time domain inter-cell interference coordination techniques specified in LTE Rel. 10 standard improves the throughput of picocell-edge users by protecting them from macrocell interference. On the other hand, it also degrades the aggregate capacity in macrocell because the macro base station (MBS) does not transmit data during certain subframes known as almost blank subframes. The MBS data transmission using reduced power subframes was standardized in LTE Rel. 11, which can improve the capacity in macrocell while not causing high interference to the nearby picocells. In order to get maximum benefit from the reduced power subframes, setting the key system parameters, such as the amount of power reduction, carries critical importance. Using stochastic geometry, this paper lays down a theoretical foundation for the performance evaluation of heterogeneous networks with reduced power subframes and range expansion bias. The analytic expressions for average capacity and 5th percentile throughput are derived as a function of transmit powers, node densities, and interference coordination parameters in a heterogeneous network scenario, and are validated through Monte Carlo simulations. Joint optimization of range expansion bias, power reduction factor, scheduling thresholds, and duty cycle of reduced power subframes are performed to study the trade-offs between aggregate capacity of a cell and fairness among the users. To validate our analysis, we also compare the stochastic geometry based theoretical results with the real MBS deployment (in the city of London) and the hexagonal-grid model. Our analysis shows that with optimum parameter settings, the LTE Rel. 11 with reduced power subframes can provide substantially better performance than the LTE Rel. 10 with almost blank subframes, in terms of both aggregate capacity and fairness.
UAV assisted heterogeneous networks for public safety communications
2015 IEEE Wireless Communications and Networking Conference Workshops (WCNCW), 2015
On the capacity analysis of HetNets with range expansion and eICIC
2013 IEEE Global Communications Conference (GLOBECOM), 2013
HetNet capacity with reduced power subframes
2014 IEEE Wireless Communications and Networking Conference (WCNC), 2014
Spiral resonators for optimally efficient strongly coupled magnetic resonant systems
Wireless Power Transfer, 2014
ABSTRACT The wireless efficiency of the strongly coupled magnetic resonance (SCMR) method greatly... more ABSTRACT The wireless efficiency of the strongly coupled magnetic resonance (SCMR) method greatly depends on the Q-factors of the TX and RX resonators, which in turn are strongly dependent on the geometrical parameters of the resonators. This paper analytically derives the equations that can be used to design optimal spiral resonators for SCMR systems. In addition, our analysis illustrates that under certain conditions globally maximum efficiency can be achieved.
Device-to-device discovery based on 3GPP system level simulations
2013 IEEE Globecom Workshops (GC Wkshps), 2013
ABSTRACT Device-to-device (D2D) communication as an underlay to cellular networks has gained incr... more ABSTRACT Device-to-device (D2D) communication as an underlay to cellular networks has gained increasing popularity as a technology component to LTE-Advanced. Through D2D communications, user equipments (UEs) in close proximity to each other, may communicate directly instead of through the eNodeB. This helps to achieve better performance than that offered via eNodeB (two-hops) by offloading eNodeB resources, and enables new types of services. This paper provides an overview of the new agreements in 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Radio Access Networks (RAN) related to evaluation methodology and channel modeling for D2D discovery and communications. We also present a system level simulation environment based on 3GPP assumptions and a performance evaluation of three different D2D discovery algorithms.
USRP-based indoor channel sounding for D2D and multi-hop communications
WAMICON 2014, 2014
ABSTRACT In wireless networks, mobile nodes with limited power budget must rely on multi-hop tran... more ABSTRACT In wireless networks, mobile nodes with limited power budget must rely on multi-hop transmissions so as to achieve reliable communication with a distant peer device. Hence, it is of paramount importance to study the characteristics of wireless transmission over multihop links and its benefits over single-hop communication. In this work, a simulator is developed to assess the bit error rate (BER) performance of multi-hop, multi-carrier communication systems. The channel model used in the simulator is developed based on the channel statistics obtained through indoor channel measurements performed using the universal software radio peripherals (USRPs). As the bandwidth supported by a USRP device is much smaller than the channel bandwidth of interest, we use a frequency domain approach to measure the impulse response of wide band channel. By using the channel measurements, we show the impact of communication distance on the delay spread and coherence bandwidth of the channel. Our simulation results with orthogonal frequency division multiplexing (OFDM) systems show that the BER performance of multi-hop communication is better than the single-hop communication. The BER performance difference between the two cases becomes more significant for wider subcarrier frequency spacing.
Traditional regulatory methods for spectrum licensing have been recently identified as one of the... more Traditional regulatory methods for spectrum licensing have been recently identified as one of the causes for the under-utilization of the valuable radio spectrum. Governmental agencies such as the Federal Communications Commission (FCC) are seeking ways to remove stringent regulatory barriers and facilitate broader access to the spectrum resources. The goal is to allow for an improved and ubiquitous sharing of the precious radio spectrum between commercial service providers.
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Papers by Arvind Merwaday