A Universal Code-Modulated Path-Sharing Multi-Antenna Receiver

Conventional multi-antenna systems require multiple RF chains, baseband blocks, and analog-to-digital converters (ADC) in the receiver front-end, mandating substantial increases in power consumption and chip area. In this paper, we introduce a new universal code-modulated path-sharing multi-antenna (CPMA) receiver architecture suitable for any multi-antenna scheme including spatial multiplexing and spatial diversity. The receiver utilizes code modulation to distinguish different antenna signals before combining them in the analog domain. The combined signals propagate through a single shared path and are later recovered in the digital domain for further processing. Due to the spread spectrum nature of code modulation, a larger bandwidth is required for the blocks in the shared path. To alleviate this effect, we examine the use of non-orthogonal signature codes. Analysis and simulation results indicate that by properly selecting non-orthogonal code sets, the spreading factor, and therefore, the overall analog signal bandwidth is reduced while incurring minimal performance degradation.