Optical wireless communications within fourth-generation wireless systems [Invited]

It is commonly agreed that the next generation of wireless communication systems, usually referred to as fourth-generation (4G) systems, will not be based on a single access technique but will encompass a number of different complementary access technologies. We outline some of the radio frequency (RF) standards that will be used and assess where optical wireless (OW) communications may play a role. Further, we outline some future research challenges and opportunities. (c) 2005 Optical Society of America.