06870515 is referenced by 61 patents and cites 7 patents.

Previous MIMO systems have used spatially diverse antenna elements in order not to reduce the number of orthogonal channels that can be realized. The present invention recognizes that this leads to large antenna sizes, as compared to multiple beam antenna systems which use closely spaced antenna elements. In order to provide a compact antenna unit, while still allowing a MIMO system to be exploited, the present invention recognizes that polarization diversity only can be used in a MIMO system without the need for spatially diverse antenna elements. Closely spaced antenna elements are used and this enables a compact MIMO antenna unit to be provided. In addition, such MIMO systems with polarization diversity but no spatial diversity can advantageously be used in line of sight situations and also combined with multi-beam antenna systems to further increase capacity.

Title
MIMO wireless communication system
Application Number
9/975653
Publication Number
6870515 (B2)
Application Date
October 11, 2001
Publication Date
March 22, 2005
Inventor
Chris Ward
Bishops Stortford
GB
Martin Smith
Chelmsford
GB
Dean Kitchener
Brentwood
GB
Agent
Barnes & Thornburg
Assignee
Nortel Networks
CA
IPC
H01Q 021/24
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