Diffusive MIMO Molecular Communications: Channel Estimation, Equalization and Detection

In diffusion-based communication, as for molecular systems, the achievable data rate is low due to the stochastic nature of diffusion which exhibits a severe inter-symbol-interference (ISI). Multiple-Input Multiple-Output (MIMO) multiplexing improves the data rate at the expense of an inter-link interference (ILI). This paper investigates training-based channel estimation schemes for diffusive MIMO (D-MIMO) systems and corresponding equalization methods. Maximum likelihood and least-squares estimators of mean channel are derived, and the training sequence is designed to minimize the mean square error (MSE). Numerical validations in terms of MSE are compared with Cramer-Rao bound derived herein. Equalization is based on decision feedback equalizer (DFE) structure as this is effective in mitigating diffusive ISI/ILI. Zero-forcing, minimum MSE and least-squares criteria have been paired to DFE, and their performances are evaluated in terms of bit error probability. Since D-MIMO systems are severely affected by the ILI because of short transmitters inter-distance, D-MIMO time interleaving is exploited as countermeasure to mitigate the ILI with remarkable performance improvements. The feasibility of a block-type communication including training and data equalization is explored for D-MIMO, and system-level performances are numerically derived.Comment: Accepted paper at IEEE transaction on Communicatio

Motorcycle Potential Problems in Jakarta

After the economic crisis in 1997, motorcycles become a popular transport mode in Indonesian cities.However this condition leads to large number of violation and accident rate. This study tried to discuss howthis problem started and what possible measure can be taken to solve the problems, mainly based on literaturereview. The traffic data used were compiled from the data provided by PT Pamintori Cipta. Interview surveywas conducted to find people perception of motorcycles issues. The conclusion suggests that there is a needof further comprehensive study to find out what condition that makes motorcyclists voluntary return to usepublic transport and social engineering and intensive training program should be implemented for youngergeneration to improve traffic condition in Jakarta