MIMO communication system having deterministic channels and antenna arrangement method therfor
A MIMO communication system having deterministic channels the orthogonality of which can be ensured even if a reflected wave other than the direct wave is present during line-of-sight communication is provided. The MIMO communication system is used in a line-of-sight environment and has deterministic channels between the transmission side where a plurality of transmission antennas are arranged and the reception side where a plurality of reception antennas are arranged. The transmission side, the reception side, or both transmission and reception sides of the MIMO communication system have a channel matrix calculation processing means for calculating a channel matrix for establishing an orthogonal channel as a communication channel. The transmission and reception antennas forming the channel matrix are horizontally arranged with respect to the ground.
1. A Multiple-Input/Multiple-Output (MIMO) communication system having deterministic channels between a transmission side where a plurality of transmission antennas are arranged and a reception side where a plurality of reception antennas are arranged and used in a line-of-sight environment, the system comprising
a channel matrix calculation processing unit for calculating a channel matrix for constructing orthogonal channels as a channel on a transmission or reception side or both of the transmission and reception sides,
wherein the plurality of transmission antennas and the plurality of reception antennas constituting the channel matrix are vertically arranged with respect to the ground in each of the transmission and reception sides, and an antenna height of an antenna arranged at a lowest position in each side from the ground is made to be an integral multiple of an antenna interval, the antenna interval being an interval between adjacent antennas in each side and being common in each side and to both sides.
2. A Multiple-Input/Multiple-Output (MIMO) communication system having deterministic channels between a transmission side where a plurality of transmission antennas are arranged and a reception side where a plurality of reception antennas are arranged, the system comprising
a channel matrix calculation processing unit for constructing orthogonal channels as the channels by setting geometric parameters of the channels concerning antenna distance so that an eigenvalue of the channel matrix becomes a multiplicity condition, and performing, on the transmission or reception side, a matrix calculation using a unitary matrix constituted based on singular vectors obtained from the eigenvalue or singular vectors obtained from a linear combination of eigenvectors,
wherein the plurality of transmission antennas and the plurality of reception antennas constituting the channels are vertically arranged with respect to the ground in each of the transmission and reception sides, and an antenna height of an antenna arranged at a lowest position in each side from the ground is made to be an integral multiple of an antenna interval, the antenna interval being an interval between adjacent antennas in each side and being common in each side and to both sides.
3. The MIMO communication system having deterministic channels according to claim 1 , wherein
the channel matrix calculation processing unit updates the channel matrix for constructing the orthogonal channels in accordance with a positional variation of a transmission antenna or a reception antenna, positional variations of both of the transmission and reception antennas, or a variation of the channels.
4. The MIMO communication system having deterministic channels according to claim 2 , wherein
the channel matrix calculation processing unit sets geometric parameters of the channels so that the eigenvalue of the channel matrix becomes a multiplicity condition, and performs calculation of a unitary matrix constituted based on an eigenvector obtained from the eigenvalue or an eigenvector obtained from the linear combination of eigenvectors on one of the transmission and reception sides to thereby construct virtual orthogonal channels as the channels.
5. The MIMO communication system having deterministic channels according to claim 1 , wherein
the MIMO communication system comprises a fixed point microwave communication system using a plurality of antennas and comprises oscillators provided independently for respective antennas on one or both of the transmission and reception sides.