Space-Time Encoding with Cyclic Delay Diversity for Antenna Expansion

The patent segments the antenna system into multiple groups (first antenna group with 2 antennas using Alamouti encoding, second antenna group with additional antennas using cyclic delay diversity). This segmentation allows different diversity schemes to operate simultaneously on different antenna subsets, maintaining the reliability benefits of Alamouti while adding capacity through CDD, thereby resolving the contradiction between diversity gain and transmission efficiency for systems with 3 or more antennas

The patent transitions from purely temporal/symbol-based diversity (Alamouti) to spatial diversity by introducing cyclic delays across multiple antennas (Cyclic Delay Diversity). This adds a spatial dimension to the diversity mechanism, allowing the system to achieve both maximum diversity gain through multiple independent fading paths and high transmission efficiency by maintaining simple receiver structure without requiring complex joint processing

The receiver processes signals from different antenna groups separately - the first antenna group signals are processed using simple Alamouti decoding while the second antenna group signals are processed using simple cyclic delay correlation. This segmentation maintains low reception complexity for each subset while enabling easy expansion to any number of antennas by simply adding more antenna groups with the same simple processing structure

The patent uses cyclic delay diversity which copies the transmitted signal across multiple antennas with different time delays. The receiver simply correlates the received signals with delayed versions of the transmitted signal, copying the simple single-antenna reception process to multiple antennas without increasing complexity, thereby enabling easy antenna expansion