| 摘要 |
<p>Free-space, line of-sight, electro-magnetic communication (i.e., via light o r microwaves) is employed to provide a wide range of communication services to geographically scattered users. A relay point or end point is typically asso ciated with each user. Each relay point receives and retransmits information via line-of-sigh t communication. The end points are also receivers and transmitters of informa tion via line-of-sight communication. Although spaced from one another, the relay and end points are close enough to one another to communicate via line-of-sight links. Hard -wired connections to the users are therefore unnecessary. Broadcast radio frequenc y communication capability may be provided as a backup for maintaining at leas t some service in the event of line-of-sight communication failure or interruption. This radio capability may additionally be used to provide cellular communication servic e to small cells associated with the relay and end points.</p> |
