For conventional authentication protocols, distribution of session keys and maintenance of large databases are serious problems especially for large-scale wireless networks. ID-based authentication protocol eliminates the problem while it contributes the heavy computation load. We propose a hybrid end-to-end authentication and key agreement (AKA) protocol which provides authentication and key exchange between both end entities. It not only eliminates the drawbacks of conventional protocols but also reduces the computation load. Services of message confidentiality, caller ID confidentiality, service request intractability, and fraud control are provided. Roaming and handover, are also taken into consideration here.

The Space Shuttle orbiter (SSO) Ku-band single access return (KSAR) link and the Space Station Freedom (SSF) KSAR link via the tracking and data relay satellite system (TDRSS) use the same carrier frequency. The interference between spacecraft is minimized by opposite antenna polarizations and by TDRSS antenna beam pointing, but if the SSF and SSO are in close proximity, it is expected that mutual interference will be significant. It is shown that a simplified analytical approach will yield adequate accuracy for the expected range of operating conditions. Relative degradation in bit-energy-to-thermal-noise power spectral density ratio to achieve a 10/sup -5/ coded bit-error probability is determined to be 4 dB for the Ku-band SSO-to-TDRS I-channel return link with a 4.5-dB effective signal-to-interference total power ratio (S/I) when the Ku-band SSF-to-TDRS return link interferes. For the Ku-band SSF-to-TDRS return link, both analysis and simulation results yield a relative signal degradation of 0.4 dB at the effective S/I=21.6 dB.>

This paper is intended to provide a comprehensive description of the Space Shuttle communications and tracking system design, development, and system operations. Areas of special innovative communications techniques implemented by the Space Shuttle such as source encoding, channel encoding, spread spectrum, and digital modulation are emphasized. In addition, the role of the Electronics Systems Test Laboratory in the development of the system is discussed.

The purpose of this paper is to present a theory which can be used to determine the effects which phase noise sources produce on the bit error probability performance of phase coherent links. The paper begins by presenting typical math models for phase noise sources known to exist in frequency generators. These phase and frequency instability models are then incorporated into equivalent loop models known to characterize the performance of CW and Costas loops. From these equivalent loop models a general analysis is presented which can be used to: (1) determine optimum tracking performance (minimum phase-error jitter) and (2) evaluate bit error probability degradations due to combined phase noise sources. This paper concludes with an example which applies the theory presented to assess the impact on link performance due to phase noise sources generated in the ShuttleS-band payload interrogator. By careful design and control of the power spectral densities of the phase noise sources one can design a system so that the phase noise has a small effect on bit error probability performance.

This paper systematically analyzes the signal-signal-to-noise ratio degradations which can potentially occur due to data asymmetry in digital transmission systems. Suitable asymmetry models are developed and error probability performance for various types of data detectors (integrate-and-dump filter, filter-sample detector, and gated-integrate-and-dump filter) is derived. Although this work was done to resolve problems being encountered in the ShuttleKu-band return link design, specifically for the 50 Mbit/s convolutionally encoded channel (NRZ format), generalizations are made which provide results for other cases of interest (otherKu-band return link channels, or other systems entirely). This paper therefore considers Manchester data formats (in addition to NRZ) and uncoded transmission (in addition to convolutionally coded transmission). The effects of bandlimiting are also considered.