Comprehensive Survey of Galvanic Coupling and Alternative Intra-Body Communication Technologies

PHY Design and Implementation of a Galvanic Coupling Testbed for Intra-Body Communication Links

“…For the second case of communication inside the body, several research works have been conducted to evaluate the path loss along and inside the human body using either narrowband radio signals or ultra wide band (UWB) ones. All of them confirmed that the radio signals experience high losses [2], [3] that translate in unwanted tissues heating and energy replenishment for the sensors already implanted. Alternative non-RF techniques are thus required.…”

“…• the proposed architecture shows high flexibility since all the parameters may be changed in the PC control panel, such as the sampling frequency, or in the Matlab programs (for example carrier frequency and modulation order) thus allowing a quick evaluation of the resulting effects; • the testbed, although simple, implements specific PHY methods, including frequency, phase and time recovery, able to achieve almost error free intra-body communication, while existing test systems only obtain a bit error rate (BER) in the range of 10 −3 and 10 −6 [3], [8], [9]; • extensive experimental tests are conducted with a real chicken tissue in different environmental conditions. The significance of this experimental study is that we are able to achieve almost error free communication, mainly due to the developed carrier frequency recovery scheme, that translates in a robust and reliable communication, a valuable result in medical applications [11].…”

“…Thus, it has been employed for IBC since the human body consists of 65% water [12]. Works on ultrasound communication have shown that the propagation loss in the body is much lower than of RF communications thus resulting in a promising IBC technique [3].…”

“…Capacitive coupling is based on two circuits that share the same electric field and cause a flow of energy from one circuit to the other one [3]. CC in intra-body uses a couple of electrodes at the transmitter and receiver, respectively, where only one of the electrodes at each side is attached to the body, while the other one is floating (ground electrode needs to be only in proximity) [1].…”

“…CC in intra-body uses a couple of electrodes at the transmitter and receiver, respectively, where only one of the electrodes at each side is attached to the body, while the other one is floating (ground electrode needs to be only in proximity) [1]. The body behaves as a conductor of the electric potential and the external ground acts as a return path for the signal [3]. In this way, the path loss highly depends on the environmental conditions, which is the main CC drawback, that however is able to achieve long distance inside the body [3], a valuable feature for IBC.…”