“…Radio frequency interference, which is the signal emitted from an undesired transmitter, could degrade performances of a victim receiver. The power level of interference at the victim receiver's input (IF output) is generally given as [37]- [39]…”
Section: Radio Interference Modeling For Coexistence Studymentioning
The fifth-generation (5G) cellular mobile communications look promising with features that can help improving consumer experience and satisfaction. To be able to provide these features, more spectrum is required according to the Shannon-Hartley theorem. Spectrum is, however, a finite and scarce resource, and it can be allocated to a new service only when the spectral coexistence with other incumbents is ensured. New waveforms for 5G that differ from the conventional orthogonal frequency-division multiplexing (OFDM) are required in order to have a superior performance in terms of out-of-band emissions and to be able to utilize the fragmented spectrum in different bands. We developed the analytical models for evaluating the out-of-band emissions of the conventional cyclic prefix (CP)-OFDM as well as its alternatives: windowed OFDM and filtered OFDM, using their signal spectral modeling. The resulting expressions for the power spectral density (PSD) and the frequency-dependent rejection (FDR) involve simple closed-form expressions or easily computable integrals. We applied the expressions to the advanced minimum coupling loss model for assessing the feasibility of the spectral coexistence between the potential 5G systems (with linearized or nonlinear power amplifier) and the incumbent radar systems. The numerical simulation results indicate that both the windowed OFDM and filtered OFDM guarantee the coexistence at the low expense of the spectrum utilization and their coexistence performance can be reduced and reversed with nonlinearity distortion of the power amplifier.
“…Radio frequency interference, which is the signal emitted from an undesired transmitter, could degrade performances of a victim receiver. The power level of interference at the victim receiver's input (IF output) is generally given as [37]- [39]…”
Section: Radio Interference Modeling For Coexistence Studymentioning
The fifth-generation (5G) cellular mobile communications look promising with features that can help improving consumer experience and satisfaction. To be able to provide these features, more spectrum is required according to the Shannon-Hartley theorem. Spectrum is, however, a finite and scarce resource, and it can be allocated to a new service only when the spectral coexistence with other incumbents is ensured. New waveforms for 5G that differ from the conventional orthogonal frequency-division multiplexing (OFDM) are required in order to have a superior performance in terms of out-of-band emissions and to be able to utilize the fragmented spectrum in different bands. We developed the analytical models for evaluating the out-of-band emissions of the conventional cyclic prefix (CP)-OFDM as well as its alternatives: windowed OFDM and filtered OFDM, using their signal spectral modeling. The resulting expressions for the power spectral density (PSD) and the frequency-dependent rejection (FDR) involve simple closed-form expressions or easily computable integrals. We applied the expressions to the advanced minimum coupling loss model for assessing the feasibility of the spectral coexistence between the potential 5G systems (with linearized or nonlinear power amplifier) and the incumbent radar systems. The numerical simulation results indicate that both the windowed OFDM and filtered OFDM guarantee the coexistence at the low expense of the spectrum utilization and their coexistence performance can be reduced and reversed with nonlinearity distortion of the power amplifier.
“…Then, we adopt the Ffrequency-dependent rejection (FDR) to investigate the interference to be mitigated according to the spectrum masks. This is defined as the summation of the on-tune rejection (OTR) and the off-frequency rejection (OFR) as follows: FDR(n ch ) k = OTR + OFR(Δ𝑓 ), where Δf is the difference between center frequencies of CF(n ch ) for RLAN and f k for k-th FWS [31]. Here, the OTR and OFR are defined as follows [32]:…”
Section: Calculation Methodologies For Spectrum Sharing Informationmentioning
confidence: 99%
“…This is defined as the summation of the on‐tune rejection (OTR) and the off‐frequency rejection (OFR) as follows: , where Δ f is the difference between center frequencies of CF( n ch ) for RLAN and f k for k ‐th FWS [31]. Here, the OTR and OFR are defined as follows [32]: …”
With the increasing demand for unlicensed spectrum, several regulators have been opening up the 6-GHz band for unlicensed use while ensuring compliance with the technical requirement to avoid harmful interference in the existing primary services (PSs). In this paper, we present two methodologies, a channel-based method and a frequency-based method, which are applicable to a frequency coordination system that calculates the permissible transmit power in the channels or frequencies available to a secondary service (SS). In addition, we have demonstrated that the available transmit power of an SS can be maximized by adjusting the power allocation of the assigned resource units under the condition that the channel of the SS is partially overlapped with that of the PS. Based on the analysis results, it is suggested that it would be better to utilize the two methods selectively according to the operating channel conditions of the PS and the SS.
“…With OFDM modulation, many subcarriers at adjacent frequencies are used in a single channel. This, in turn, can lead to mutual interference, but due to the orthogonality of the subcarriers, this does not happen [10]. Therefore, the application of OFDM to-maximize the spectral efficiency of the channel without interference.…”
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