Page 53 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 3 – Internet of Bio-Nano Things for health applications

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 3

Medical
personnel
A Abnormality monitoring
(Cooperative MC systems)
Bidirectional
communication
A through EM
D Drug delivery waves
(MIMO-MC
systems) R
R Molecular D Access point Internet
router

Bio-cyber interface
Molecular (Machine learning based MC systems)
signal
EM based
signal

Fig. 9 – Different MC systems for different applications in IoBNT [17].

Transmitted of bit‑1 or bit‑0, which was transmitted using the OOK
impulse modulation scheme. Further, in [48], memory‑less and
Pulse Channel
N tx δ(t) shaping impulse Received signal memory‑basedreceiverdesignsbasedonaMAPrulewere
filter response proposed for OOK modulated symbols. In this work, the
received signal PDF was considered as a Gaussian mix‑
p(t) h(t) y(t)
t=0 ture model in presence of ISI and the detection thresh‑
old was evaluated iteratively by minimizing the proba‑
n(t) bility of error. Furthermore, the authors in [49] consid‑
Signal dependent ered rectangular pulse transmission using an OOK mod‑
noise ulation scheme, where a non‑coherent detection was
5
proposed which utilized the difference between the ac‑
cumulated concentration of molecules in successive bit‑
Fig. 10 – A general block diagram of an MC system.
intervals. This scheme also provides ISI mitigation ca‑
proposed in [45], where type‑A and type‑B molecules pability. Further, this scheme gives better BER perfor‑
were used for bit‑1 and no molecule for bit‑0. As shown in mance than the coherent MAP and MMSE schemes if chan‑
Fig. 12, in contrasttothe OOK modulationscheme, type‑B nel memory length is restricted to 10.
molecules were released for bit‑1 before each bit‑0 to re‑
duce the effect of ISI. In addition to the MTSK modulation In [50], an OOK modulation scheme has been employed at
scheme, receiver‑based ISI mitigation using a Decision the transmitter, while asynchronous peak detection and
Feedback Filter (DFF) was proposed where the compu‑ energydetectionschemeswithandwithoutdecisionfeed‑
tational complexity of DFF was independent of the num‑ back were proposed at the receiver. In an asynchronous
ber of ilter taps. Further, the DFF is less complex than peak detector without decision feedback, all the sam‑
the conventional DFE and MMSE equalizers. The results ples within a symbol interval were compared to ind the
showed that DFF signi icantly reduced the ISI from the maximum value, and the maximum value was compared
received signal before comparing it with a threshold for against the threshold for detection. Further, in the case
detection. On the other hand, Impulse Transmission (IM) of detection with decision feedback, the expected ISI was
and pulse transmission (PAM) schemes were proposed in subtracted from the total received signal and then asyn‑
[46]. In this work, the energy‑based detection using the chronous peak detection was performed. A similar proce‑
binary hypothesis testing was proposed in the presence dure was considered for energy detection with and with‑
and absence of ISI. The results therein demonstrated that out decision feedback. It is shown that the energy‑based
the IM transmission scheme has a higher probability of detection with ISI cancellation outperforms the other pro‑
detection in comparison to PAM. posed schemes.
A convex optimization problem that minimizes the er‑
A low complexity adaptive threshold detection scheme
has been proposed in [47] where the received signal in ror probability for determining the detection threshold
the current bit‑interval was compared with the received 5 In contrast to the coherent detector, a non‑coherent detector does not
signal in the previous bit‑interval to decide in the favor require Channel State Information (CSI) at the receiver nano‑machine.

© International Telecommunication Union, 2021 41