| 摘要 |
<p>Coverage in a cellular communications system is provided by a plurality of relays (R) within range of a base station (200). Each relay defines a service area which can overlap that of a neighbouring relay to serve subscribers. An antenna arrangement at the base station forms directional beams (230, 240) and can vary the radiation pattern of its directional beams to selectively illuminate relays as required. An individual relay may be illuminated by a narrow beam at a particular frequency, or a group of relays may be illuminated at a common frequency in a simulcast fashion. This allows the system to adapt to changing traffic conditions.</p> |
