A Framework for Code Division Multiple Access Wireless Power Transfer

Abstract

The availability of energy is one of the major hindrances to unlocking the massive potential of electronic devices. Powering a highly connected network of devices requires multiple access and a wireless power transfer (WPT) solution that is scalable and capable of maintaining a constant power flow regardless of reconfiguration (mutability) and electromagnetic environment (power flow selectivity). In this paper, we present a framework for the implementation of code division multiple access wireless power transfer (CDMA-WPT) for enabling WPT among multiple transmitters and multiple receivers simultaneously. CDMA-WPT maintains power flow selectivity and is easily scalable. An inverter/rectifier topology is presented for the hardware implementation of CDMA-WPT. A design process for practical co-design of high-performance hardware and obtaining a code set is also presented. We demonstrate the hardware implementation of CDMA-WPT using two transmitters and two receivers maintaining a nearly constant 5 W operation with nearly 75 % dc-dc efficiency, and four transmitters and four receivers maintaining a constant 4 W operating with greater than 70 % dc-dc efficiency. . This paper is accompanied by a video hardware demonstration in real-time the difference between using orthogonal codes in CDMA versus conventional single-frequency WPT using 4 transmitter-receiver pairs; conventional single-frequency WPT shows up to a 100 % deviation from the intended transfer power as opposed to 8.1 % for orthogonal codes in CDMA.INDEX TERMS Wireless power transfer (WPT), code division multiple access (CDMA), current-mode class-D (CMCD), internet of things (IoT), power amplifier, high-efficiency, resonant converter.

Fairness-Aware Resource Allocation in Multi-Source WPCN in the Finite Blocklength Regime

“…) Based on the relaxation of term ϵ 2 ,ϵ 3 and ϵ 5 , i.e., (34) (35) (36), we have the inequality function (33). When γ i ≥ 1 and r i ≥ 0.0683 holds, ν 1 , ν 1 and ν 1 respectively satisfies ν 1 ≥ 0.0039,ν 2 ≥ 0.0273 and ν 3 ≥ 0.0106, which indicates that f ≤ 0, thus d 2 xi dn 2 i ≤ 0 holds.…”

“…Moreover, upperbounded by the hardware, the transmit RF power from a single source is limited, i.e., the achievable WPT capacity is restricted, which may lead to insufficient power supplement and accordingly result in low effective WPT. To cope with this, introducing more WPT sources has been verified as an effective solution [35]. By combining the multiple RF signals from multisource, a higher WPT efficiency and a higher energy ceiling can be achieved, which contributes to further system performance enhancement.…”

A Literature Survey with the Focus on Magnetically Coupled Wireless Power Transfer Systems Developed for Engineering and Biomedical Applications

“…Jiang et al presents fractional-order WPT that includes a fractional-order capacitor (Figure 1) based on the insensitivity of circuit on the resonant frequency where the two important transfer efficiency and output power parameters were stable and consistent [1]. In [23], power flow selectivity and scalability specifications were investigated for a multiple access WPT. In that work, code division multiple access wireless power transfer (CDMA-WPT) was presented that let to achieving a stable power flow among various connected networks of devices.…”

Feedline Separation for Independent Control of Simultaneously Different Tx/Rx Radiation Patterns

“…Code segment access (CDMA) uses the same carrier frequency. But there are different codes in [22]. The weakness of CDMA is that the number of users in the network deteriorates the overall service quality.…”