RF Sampling for Multi-band Radios

Advancements in Cellular Radio Technology

Recent breakthroughs in high-speed data converters are revolutionizing cellular infrastructure by enabling direct digitization and generation of signals at frequencies up to several gigahertz. This technology replaces traditional radio-frequency (RF) components like mixers and local oscillators.

RF-sampling data converters, with their wide-bandwidth capabilities and high gigasample-per-second (GSPS) speeds, are facilitating radios that can combine multiple cellular bands. This leads to the development of smaller, lower-power systems, ultimately reducing the complexity and footprint of cell sites.

Architectural Comparison and Performance Analysis

This application report from Texas Instruments provides a comprehensive comparison between RF sampling multi-band radio architectures, specifically utilizing the AFE7686, and conventional radio architectures. It details the analysis of expected performance against stringent 3GPP standards.

The report delves into various radio architectures, including 0-IF, IF, and Complex IF, contrasting them with the RF sampling approach. It also examines critical aspects such as receiver specifications for LTE and GSM, transmitter specifications, and emerging 5G NR cmW systems.

Performance estimation is achieved through a systematic approach, employing mathematical expressions for degradation sources and utilizing spreadsheet calculations to determine overall system performance under different conditions.

Key Components and System Considerations

The document further explores typical radio components involved in RF sampling receiver front-ends, analyzing system degradation mechanisms, and detailing receiver tests for LTE and multi-carrier GSM. It highlights the importance of components like ADCs and filters in achieving optimal performance.