Mixerless RF Transceivers for Wireless Communication

在过去二十年中，无线通信领域中发生的爆炸性增长，通过关联，见证了通信技术及其应用的增长。 这种新的增长一直在推动对数据速率指数级增长的需求。考虑到当今的技术和关于无线传输的当前知识，如果数据速率显著增加，则当前的无线通信系统和技术将不能处理该需求。为了科普这一挑战，用户带宽的增加已被认为是未来无线基础设施的潜在解决方案。为了在高度使用的一组不连续频带中提供所需的带宽，需要先进的无线通信系统。这些系统需要多标准和载波聚合能力，以更加普遍、移动的、敏捷和安全。这就要求开发软件定义的、可重构的、宽带的和认知的收发器。传统的收发器射频（RF）前端架构是基于模拟的，因此难以重新配置，并且容易受到噪声、非线性和硬件损伤的影响。此外，在频率转换中使用基于开关的混频器会产生大量杂散和谐波，需要使用不可配置、限频和体积庞大的RF滤波器仔细滤除这些杂散和谐波，这限制了这些收发器的灵活性和可重构性。一个更有说服力的替代方案是将设计转移到数字域和/或避免在频率转换中使用混频器和滤波器。拟议的研究是一项研究计划的一部分，该计划旨在为先进的通信系统开发创新的可重新配置的RF收发器，这些系统能够在宽带中工作并可以随意重新配置。在这项拟议的研究中，创新的高度可集成，可重新配置和宽带发射机架构，适用于多频段和多标准的应用将在两个不同的水平进行研究：*（i）新的发射机架构将被开发。该架构使用数字控制的“无混频器”上变频拓扑。在不使用模拟RF滤波器的情况下，所提出的拓扑将能够在宽频带上工作，因此可以根据不同的标准随意配置。* (ii)将研究用于系统行为建模和数字预失真的新模型和算法，以减轻这些拓扑中的非线性和模拟缺陷。*所提出的数字控制和线性化的发射机架构预计将具有高度可集成性，可重构性和低成本的巨大潜力，这使它们成为未来无线电系统和无处不在网络的有趣解决方案。

The explosive growth occurring in the past two decades in the wireless communication sector has, by association, seen a growth in communication technology and its applications. This new growth has been driving the need for an exponential increase in data rates. Given today's technology and current knowledge about wireless transmission, if data rates were to substantially increase, current wireless communication systems and techniques will not be able to handle the demand. To cope with this challenge, the increase in user bandwidths has been considered as a potential solution for future wireless infrastructure. In order to provide the required bandwidth in a highly used set of discontinuous frequency bands, advanced wireless communication systems are needed. These systems require multi-standard and carrier aggregation capabilities to be more ubiquitous, mobile, agile, and secure. This calls for the development of software-defined, reconfigurable, wideband and cognitive transceivers. Conventional transceiver radio frequency (RF) front-end architectures are analog-based and therefore are hard to reconfigure and are prone to noise, nonlinearity and hardware impairments. In addition, the use of switching-based mixers in frequency conversion generate a large amount of spurs and harmonics that need to be filtered out carefully using non-configurable, frequency limiting and bulky RF filters, which limit the agility and reconfigurability of these transceivers. A more compelling alternative is to move the design to digital domain and/or to avoid the use of mixers and filters in frequency conversion. The proposed research is part of a research program that aims at developing innovative reconfigurable RF transceivers for advanced communication systems that are able to operate in wideband and to be reconfigured at will. In this proposed research, innovative highly integrable, reconfigurable and wideband transmitter architectures suitable for multi-band and multi-standard applications will be investigated at two different levels: ***(i) New transmitter architectures will be developed. This architecture uses digitally controlled "mixerless" frequency up-conversion topologies. Without the use of analog RF filters, the proposed topology will be able to operate over wide frequency bands and therefore can be configured at will for different standards.***(ii) New models and algorithms for system behavioural modeling and digital predistortion will be investigated in order to mitigate the nonlinearity and analog imperfections in these topologies.***The proposed digitally controlled and linearized transmitter architectures are expected to have great potential of high integrability, reconfigurability and low cost, which make them an interesting solution for future radio systems and ubiquitous networks.**