Analytical and experimental evaluation of a novel wideband digital beamformer with on-site coding

Abstract

In this paper, we present a review of the state-of-the-art analog and digital beamformer architectures. In addition, an analytical and experimental evaluation of a novel transceiver architecture with on-site coding is conducted. The architecture features agile beam forming, jamming mitigation, and MIMO capability. The proposed architecture departs from traditional digital beamforming approaches. Specifically, a single analog to digital converter (ADC) is assigned to a group of array elements instead of having one ADC per element. To facilitate this approach, code division multiplexing is applied to each received antenna signal prior to combining them for digitization using a single ADC. In this paper, a detailed systematic evaluation of the proposed on-site coding receiver is carried out. We examine the trade-offs using non-ideal components (e.g. filters), including finite resolution ADCs and their impact on the system’s noise floor. It is concluded that the bit error rate shows minimal SNR degradation using filters of order 4 and ADCs with 10 bit resolution along with Walsh–Hadamard (WH) codes to realize on-site coding. We also present a two-channel implementation with components off-the-shelf assuming a modulated binary phase shift keying input signal and WH codes of length 8. Measurements show full signal recovery with minimal degradation.

Keywords:

• code division multiplexing
• digital beamforming
• transceivers
• wideband arrays