Method and apparatus for predicting spot beam and satellite handover in a mobile satellite communication network
US6246874A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 16, 1998 |
| Grant date | Jun 12, 2001 |
| Priority date | — |
| Expiry date | Dec 16, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W84/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for predicting when to perform spot beam and satellite handover in a mobile satellite communication network that uses the position of the mobile subscriber. The method and apparatus perform all calculations with respect to a satellite-based coordinate system, thereby eliminating the need to model the shape of the geometrically complex spot beams on the surface of the earth. The position of a mobile subscriber unit that initiates a call is tracked relative to a set of spot beam boundaries that are located equidistant between a first spot beam within which the subscriber unit is located at the time of call initiation and a set of adjacent spot beams. An interval during which the subscriber unit will cross over one of the boundaries is estimated. The spot beam into which the subscriber is traveling is identified, and the interval is adjusted until a desired level of accuracy has been achieved at which time the call is transferred from the first spot beam to the adjacent spot beam at the estimated time. For satellite handover, an angle of elevation between the subscriber unit and the satellite is calculated and compared to a threshold angle. When the angle of ele…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.