基于双电平脉冲宽度调制的低功耗可见光通信技术

Low Power Consumption Visible Light Communication Technology Based on Bilevel Pulse Width Modulation

为降低可见光通信系统中的额外功耗,对可见光通信中发光二极管结电容充放电导致的额外功耗进行了理论分析,给出了通信速率、结电容和调制方式对额外功耗的影响.基于此,提出了新型的双电平脉冲宽度调制技术,从额外功耗、带宽需求和差错性能三方面对双电平脉冲宽度调制进行了理论分析,并与非归零开关键控调制、脉冲位置调制和数字脉冲间隔调制进行了对比。结果表明,双电平脉冲宽度调制和非归零开关键控调制误时隙率相同,但额外功耗仅为非归零开关键控调制的M/2,(M为调制阶数);虽然相比于脉冲位置调制和数字脉冲间隔调制,双电平脉冲宽度调制需要更高的信噪比,但额外功耗仅为脉冲位置调制和数字脉冲间隔调制的1/2,带宽需求也小于脉冲位置调制和数字脉冲间隔调制,在功耗和带宽敏感的可见光通信系统中有较大优势。

In order to reduce the visible light communication system’s additional power consumption,the extra power consumption caused by the charge and discharge of LED junction capacitor in visible light communication is analyzed theoretically in this paper.The influence of communication rate,junction capacitance and modulation mode on the extra power consumption is given.Based on this,a novel bilevel pulse width modulation technology is proposed.Bilevel pulse width modulation is analyzed in terms of bandwidth requirement,junction capacitance and error performance,and compared with non return to zero on key modulation,pulse position modulation and digital pulse interval modulation.The results show that the two-level pulse width modulation and the non-return-to-zero on-off keying modulation have the same time slot error rate,but the additional power consumption is only M/2 of the non-return-to-zero on-off keying modulation,and M is the modulation order.Although the bilevel pulse width modulation requires higher signal-to-noise ratio compared with pulse position modulation and digital pulse interval modulation,the additional power consumption is only half of that of pulse position modulation and digital pulse interval modulation,and the bandwidth requirement is also less than that of pulse position modulation and digital pulse interval modulation,it has great advantages in power and bandwidth sensitive visible light communication system.