Collaborative Research: Low Peak to Average Power Multicarrier Signals via Coding: Fundamental Limits and Algorithms

协作研究：通过编码实现低峰值平均功率多载波信号：基本限制和算法

• 批准号: 0728572
• 负责人: Vahid Tarokh
• 金额: $ 4.5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0728572&HistoricalAwards=false
• 关键词: Collaborative; Research; Low; Peak; Average

One of the most important obstacles in deployment of high data rate, low cost, and power efficient multicarrier communication systems is the cost of front-end RF amplifiers. Multicarrier modulations offer the promise of low complexity equalization, adaptability to frequency selectivity of the channel, and efficient use of available bandwidth in cognitive networks. However, multicarrier signals consist of linear superposition of many subcarriers leading to large peak to average power ratio (PAPR) and implying the need for highly linear power amplifier. In particular, RF power amplifier becomes substantially power inefficient and expensive when its linearity region increases to accommodate signals with large PAPR. Any nonlinearity introduced by the power amplifier can cause large out-of-band leakage and reduce the transmit range of the link.While the worst case PAPR is quite large, it has been established by the investigators that the likelihood of having large peaks is small and there exist codes of almost full rate with PAPR bounded by a constant. Existing coding schemes, however, provide low PAPR and large minimum distance at the cost of substantially reducing the transmission rate. This research involves addressing both existential and algorithmic aspects of coding schemes for PAPR reduction. This research develops both probabilistic techniques and new algorithms to prove the existence and to construct pragmatic codes that not only provide low PAPR and high rate but also lead to optimizing other parameters such as capacity loss, minimum distance and out-of-band leakage.

在部署高数据速率、低成本和高能效的多载波通信系统中，最重要的障碍之一是前端射频放大器的成本。在认知网络中，多载波调制提供了低复杂性均衡、对信道频率选择性的适应性以及有效利用可用带宽的承诺。然而，多载波信号由许多子载波的线性叠加组成，导致峰值平均功率比（PAPR）很大，这意味着需要高度线性的功率放大器。特别是，当射频功率放大器的线性区域增加以适应具有大PAPR的信号时，其功率效率低下且价格昂贵。功率放大器引入的任何非线性都会造成较大的带外泄漏，降低链路的传输范围。虽然最坏情况下的PAPR相当大，但研究者已经确定，出现大峰的可能性很小，并且存在几乎全速率的编码，PAPR以常数为界。然而，现有的编码方案以大幅降低传输速率为代价，提供了较低的PAPR和较大的最小距离。本研究涉及解决存在和算法方面的编码方案，以减少PAPR。本研究发展了概率技术和新算法来证明存在性，并构建实用的码，不仅提供低PAPR和高速率，而且还导致优化其他参数，如容量损失，最小距离和带外泄漏。