Lin-nan Lee

Faster-than-Nyquist Signaling and Optimized Signal Constellation for High Spectral Efficiency Communications in Nonlinear Satellite Systems

We here consider utilizing faster-than-Nyquist (FTN) signaling to increase spectral efficiency in combination with using tight frequency roll-off, optimized signal constellations that have better energy efficiency, and allowing the satellite transponder to operate near its saturation. FTN provides a degree of freedom that allows for increasing the spectral efficiency without the need for introducing additional rings in the signal constellation, which is helpful in the presence of nonlinear transponders. Also, FTN allows for increasing the symbol rate without being adversely affected by the input multiplexing and output multiplexing (IMUX/OMUX) filters. This is because FTN does not alter the signal spectral shape. However, these advantages are gained at the expense of introducing distortion that needs to be compensated successfully. We then utilize an advanced Turbo Volterra receiver that compensates for FTN-induced distortion and nonlinear impairments. Through extensive simulations, we demonstrate substantial performance gains over a wide range of spectral efficiencies in nonlinear satellite systems with adjacent carriers.

Modulation, coding, and synchronization for mobile and very small satellite terminals, as part of the updated DVB-S2 standard

Summary After 10 years of successful deployment, the second-generation satellite standard for digital video broadcasting, DVB-S2, has recently been updated. Very low signal-to-noise ratio modes to better support mobile and very small terminal applications are part of the new standard without changing its fundamental structure. This paper provides a high-level discussion on several of the most important aspects pertaining to the new very low signal-to-noise ratio modulation and coding modes of the updated standard. Copyright

Modulation, Coding, and Synchronization for Mobile and Small Satellite Terminals: An Update of the DVB-S2 Standard

After ten years of successful deployment, the second generation satellite standard for digital video broadcasting, DVB-S2, has been updated to include very low signal-to-noise ratio modes to better support mobile and very small terminal applications without changing its fundamental structure. This paper provides a high level discussion on several of the most important aspects of the updated standard.

DVB-S2X: An Update to DVB-S2

After ten years of successful deployment, the second generation satellite standard for digital video broadcasting, DVB-S2, has been updated with several new features without changing its fundamental structure. This paper provides a high level discussion on several of the most important additions to the new standard.

Third Generation Wireless Communication Technologies

The debate on the third generation wireless system is not about the selection of the core technologies, such as CDMA versus TDMA. Rather, it is on whether the design objectives properly address the market needs and whether there are sufficient technical innovations to achieve these objectives. This chapter discusses the essential design objectives for a successful third generation wireless system. A number of key innovations intended to meet these objectives are presented. We will briefly describe the cdma2000 forward and reverse link design. In the forward link an alternative approach for the 3X mode that exhibits advantages of two approaches currently included in the cdma2000 standard is outlined. In the reverse link, we will present a media access scheme that combines PRMA for large packets and ISMA with capture message for short packets to significantly improve the efficiency of channel utilisation for high-speed data transmission. In both the forward and reverse links, Turbo FEC codes further increase the underlying channel capacity by 50–60 percent. By combining an efficient reverse link multiple access architecture, and optimised FEC coding techniques, third generation wireless systems can reach an unprecedented level of performance in high-speed packet data delivery and improved voice capacity with minimum impact on implementation complexity.

Asynchronous Scrambled Coded Multiple Access (A-SCMA) - A New High Efficiency Random Access Method

Fixed, portable and mobile terminals use Random Access (RA) to transfer data or request more spectrally efficient dedicated resources. This paper describes a new multiple access scheme, A- SCMA, that operates with unsynchronized transmission and low power, making it particularly suitable to small machine-to-machine communications in satellite or terrestrial applications. A multicarrier version operates with large and variable packet sizes without reduced throughput or large delays.

Spread Asynchronous Scrambled Coded Multiple Access (SA-SCMA) - A New Efficient Random Access Method

Asynchronous Scrambled Coded Multiple Access (A- SCMA) has been shown to offer high spectral efficiencies on Random Access (RA) channels. This paper describes a new multiple access scheme, SA- SCMA, that adds spreading. Even modest spreading provides significant gains in spectral efficiency, while the use of large RRC rolloff combined with adjacent channel interference cancellation (ACIC) further enhances performance. Spectral efficiencies achieved are high enough to offer data transfer over RA, eliminating the usual 2-way propagation delay needed to assign resources, lowering latency, an important consideration for geostationary satellite inroutes. Additionally, spreading reduces flux density, enabling smaller antenna apertures needed for lower cost applications. The use of SA- SCMA on a saturated radio to further reduce user terminal cost is also discussed.

New DVB‐S2X constellations for improved performance on the satellite channel

Summary Digital Video Broadcasting via satellite second generation has experienced worldwide adoption because of its revolutionary and yet practical physical layer technology and its flexibility. Recently, the standard has been updated with several new features without changing its fundamental structure. This paper provides a high-level discussion on several of the most important additions to the new standard with particular emphasis on some of the new signal constellations. Copyright

Applying Near Shannon-limit Codes to Wireless Communications

Tremendous progress has been made on channel coding techniques during the last decade, starting from the invention of turbo codes and the rediscovery of the low-density parity check (LDPC) codes. These codes essentially closed the gap between the Shannon capacity limit and practical implementation. Commercial adoption of these new coding techniques, however, depends heavily on the introduction of the technology into communication standards. In this paper, we will briefly review the considerations when turbo codes and LDPC codes were introduced to the 3rd generation wireless standards (3GPP& 3GPP2), and the digital video broadcast for satellite standard (DVB-S2), respectively. We will then examine a few possible approaches to take advantage of these powerful codes for future wireless channels.

Geosynchronous Satellite Communications

In this article, we discuss the development of the geosynchronous satellite concept. We explore frequency bands and orbital slots, satellite antenna beam patterns, transmission techniques, multiple-access techniques and onboard processing. Also included is a discussion of satellite communications system equipment. We conclude with a section on GEO satellite system link budgets. Keywords: geosynchronous satellite communications; development; frequency bands; orbital slots; satellite antenna beam patterns; satellite transponder; transmission techniques; round-trip propagation delay; very small aperture terminals (VSAT)