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بسم الله الرحمن الرحيم. “وقل رب زدنى علماً”. صدق الله العظيم. Teletraffic Analysis of the Next-generation Integrated Terrestrial/satellite Mobile Radio Networks. By: Waleed Eid Al-Hanafy B.Sc., Electrical Communications Engineering SUPERVISORS: Dr. Sami A. El-Dolil
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بسم الله الرحمن الرحيم “وقل رب زدنى علماً” صدق الله العظيم
Teletraffic Analysis of the Next-generation Integrated Terrestrial/satellite Mobile Radio Networks • By: • Waleed Eid Al-Hanafy • B.Sc., Electrical Communications Engineering • SUPERVISORS: • Dr. Sami A. El-Dolil • Assoc. Prof., Menoufia University, Faculty of Electronic Engineering • Dr. Mostafa A. Nofal • Assoc. Prof., Menoufia University, Faculty of Electronic Engineering
Objective of the Thesis • Investigation of the integration between terrestrial mobile systems and satellite networks. • Implementation of integrated space/terrestrial cellular model with different handoff priority schemes for global mobile communications. • Mixing data and voice services over the proposed global model.
Evolution of mobile communication systems • First generation - Analog techniques (TACS, AMPS, JMPS, NMT) - Limited capacity • Second generation - Digital technology (GSM, DECT, CT2, ERMES) - Increased system capacity and introduced more service features - Improved system quality and significant reduction in system cost
Third generation - Multimedia applications features - Trend towards globalization (communications anywhere-anytime) - Provide personal services independently of the kind of network access (PSTN, cellular, satellite, etc.) • The role of satellite - Complements terrestrial coverage areas, e.g., coverage of ships, aircraft and users in rural areas (maritime and aeronautical services) - It is crucial to support the global roaming feature - The main problem in satellite system design is the efficient use of two critical satellite resources (bandwidth and power)
Design concepts of cellular mobile radio systems: 1- Frequency reuse It is the basic idea of the cellular concept K=7
R D The carrier-to-interference ratio The frequency reuse ratio
3-Sectorization and trunking efficiency Sectorizing a cell produces two effects: First, reduces cochannel interference (i. e., improved the C/I ratio) Second, reduces trunking efficiency With C/I ratio of at least 17 dB, an omnidirectional system requires K=7, a three-sector system requires K=4, and a six-sector system requires K=3
Space-based systems • Satellite orbits - Geosynchronous orbit - Inclined orbit - Elliptical orbit • Satellite altitude - LEO - MEO - GEO
GEO Vs LEO GEO disadvantages: - 240-270ms for one-way propagation delay - Lack of coverage at far northern and southern latitudes (unachievable required elevation angles “ >40° ” even at latitudes as close to the equator as 45°) - Spacecraft design constraints such as antenna size Orbit choice limitations: Van Allen radiation belts ranging from about 1,500 to 5,000 km and from 13,000 to 20,000 km
Satellite constellations - Orbital altitude - Minimum elevation angle
Mobile radio channel characteristics Free space propagation model: Satellite communication Short line-of-sight radio links 20 dB/decade path-loss slope Mobile propagation model: 40 dB/decade path-loss slope Where, m(t) is called local mean, also called slow fading, long-term fading, or log-normal fading The factor r0 is called multipath fading, short-term fading, or Rayleigh fading
Short-term fading Rician fading: Direct wave path (path clear from the terrain contour) Line-of-sight path (path clear from buildings) Rayleigh fading: Out-of-sight condition
Global system design criteria : Global coverage LEO or GEO satellite constellations Different user’s densities Multilayered system Handoff priority verification Different H.O schemes
Handoff priority schemes • Reserved channel scheme • N-times retry scheme • Queuing scheme • Sub-rating scheme
Handoff management • Horizontal handoff Handoff between cells in the same layer • Vertical handoff Handoff between cells in different layers
Call Blocking Call arrival New call handling
Call Forced Termination Call arrival Handoff call handling
Performance analysis • Microcell level: • Arrival call rates
Channel holding time State-transition diagram
State-transitions probabilities Probability of finding no channel being busy Probability of finding j-channels being busy
Macrocell level: • Arrival call rates
Channel holding time State-transition diagram
Spotbeam cell level: • Arrival call rates
Channel holding time State-transition diagram
Users classification • Terrestrial-only users, who access only the terrestrial • subnetwork at the microcell and macrocell layers. • Satellite-only users, with access only to the satellite sub network. • Dual-mode users using dual-mode telephone sets, to enable them to access both the terrestrial and the satellite sub network.
Terrestrial-only users The overall blocking and handoff failure probabilities are: The weighted blocking and handoff failure probabilities are:
Satellite-only users The overall and weighted blocking probabilities are: The overall and weighted handoff failure probabilities are:
Dual-mode users The overall blocking and handoff failure probabilities are: The weighted blocking and handoff failure probabilities are: