Out Of Band Emission Research Articles

Improving GFDM Symbol Error Rate Performance using “Better than Nyquist” Pulse Shaping Filters

Fourth generation (4G) cellular systems have been optimized to provide high data rates and reliable coverage to mobile users. New waveforms at the physical layer are needed. Generalized frequency division multiplexing (GFDM) is a candidate modulation for the fifth generation (5G) standard based on multi-branch multicarrier filter bank approach. A main characteristic of GFDM is its low out of band emission, achieved by means of a flexible time-domain pulse shaping of individual subcarriers. In this paper, the influence of the improved “Better than Nyquist” pulse shaping filters on symbol error rate (SER) performance of the GFDM system in the case of zero forcing (ZF) receiver is investigated. We considered their use in GFDM to evaluate the impact on SER performance in case of 16-QAM transmission over an additive white Gaussian noise channel. Moreover, we also considered the concept of the wavelet for better time-frequency localization of the pulse shaping filters by using the Meyer auxiliary function. Numerical results are reported to demonstrate the superior SER performance achieved.

The APT Frequency Arrangement in the 700 MHz: Reflections on the International Spectrum Management Regime

Following WRC-12, discussions have emerged with regard to the frequency arrangements in the 700 MHz band, out of band emissions (OOBE) of the mobile terminals below 694 MHz considering the allocation of the 694-790 MHz band to the mobile service. These discussions have shown that there is a tendency to partially harmonise with the APT plan and to adopt APT OOBE values. This reflects the emerging approach of countries in Regions 1 and 2 that are aligning themselves with Region 3 to lower the cost of end user equipment. Countries such as Australia and New Zealand are leading the discussion in Region 3. The 700 MHz issue has revealed that the ITU-R decision making procedures are mostly based upon consensus with the possibility of few countries blocking the discussion. Moreover, it suggests that there is a need to revise the current ITU-R structure of three regions.

The APT Frequency Arrangement in the 700 MHz: Reflections on the International Spectrum Management Regime

Following WRC-12, discussions have emerged with regard to the frequency arrangements in the 700 MHz band, out of band emissions (OOBE) of the mobile terminals below 694 MHz considering the allocation of the 694-790 MHz band to the mobile service. These discussions have shown that there is a tendency to partially harmonise with the APT plan and to adopt APT OOBE values. This reflects the emerging approach of countries in Regions 1 and 2 that are aligning themselves with Region 3 to lower the cost of end user equipment. Countries such as Australia and New Zealand are leading the discussion in Region 3. The 700 MHz issue has revealed that the ITU-R decision making procedures are mostly based upon consensus with the possibility of few countries blocking the discussion. Moreover, it suggests that there is a need to revise the current ITU-R structure of three regions.

Basic Research on EUV Source Development

Properties of extreme ultraviolet (EUV) emission from laser generated Tin plasma were very thoroughly studied to provide experimental database for theoretical modeling and benchmarking of radiation hydrodynamic code dedicated for the EUV source research. EUV emission spectra and conversion efficiencies, defined as fraction of drive laser energy allotted for EUV ligh involved in a 2% bandwidth at 13.5nm in wavelength (i. e., inband-component) were quantitatively investigated given as a function of laser intensity, laser wavelength, target densities, and target shapes. A minimum mass target, involving a least number but sufficiently enough Tin-atoms to generate EUV light, is suggested to mitigate debris from the EUV source. A technical guideline to diminish kinetic energy of ion debris and the out-of band emission is also discussed.

Impact of a New TWTA Linearizer Upon QPSK/TDMA Transmission Performance

In transmitting a band-limited PSK/TDMA signal via satellite, the signal is distorted due to the nonlinearities of an earth station HPA and a satellite TWTA. To reduce the impairments due to these nonlinearities, a new TWTA linearizer, called a soft-limiter type linearizer (SL-LRZ), has been developed. The overall amplitude characteristic of a TWTA associated with an SL-LRZ is linear up to saturation and has a constant envelope beyond saturation. As to the AM/PM conversion characteristic, it has almost zero phase shift, irrespective of the operating point. The TWTA with SL-LRZ gives better bit error rate (BER) performance and less out-of-band emission (OBE) compared to cases where TWTA is operated by itself or with a conventional linearizer. In this paper, the impact of the new TWTA linearizer upon the transmission performance of a QPSK/TDMA signal is described. The transmission performance over a nonlinear satellite channel has been evaluated experimentally using a 120 Mbit/s QPSK modem and an INTELSAT V channel simulator.