A pulse generator is configured to generate electrical pulses of an electrical stimulation therapy. The pulse generator includes an N number of output channels and a microcontroller configured to generate instructions. The pulse generator is configured to generate different stimulation waveforms simultaneously for the output channels. The different waveforms have different waveform characteristics. A mesh electrode array includes an M number of electrodes. Each of the electrodes is configured to deliver the electrical pulses of the electrical stimulation therapy. M is at least several times greater than N. A solid state relay contains a plurality of controllable switches that is each configured to be turned on or off in response to the instructions received from the microcontroller, such that the solid state relay routes the output channels of the pulse generator to different subset of the electrodes of the mesh electrode array at different points in time.