1. Institute for Communication Systems (ICS, formerly CCSR); University of Surrey; Guildford Surrey U.K.
2. Systems and Computer Engineering Dept.; Carleton University; Ottawa Canada
3. Electrical and Computer Engineering Dept.; Texas A&M University at Qatar; Education City Doha Qatar
4. State Key Laboratory of Astronautic Dynamics; China Xi'an Satellite Control Center; Xi'an 710043 China