This project targets a situation where two persons are onboard an aircraft. Both persons have android smart phones and want to transfer a file from the SDCARD on one phone to the other, as illustrated in Figure 1 below. The use of radio transmitters and receivers is forbidden. During 2012 and 2013 we have studied the use of sound and images as way of transmitting the file. In the sound case the loudspeaker of one phone is used as transmitter and the microphone as receiver. In the visual case, the screen of one phone is used as transmitter and the camera of the other phone is used as receiver (QR-like codes where used 2013). This year we intend to study a similar technology as in 2012, i.e. the loudspeaker and microphone is used. However, this time the users has access to a suitable cable which should vastly improves the transission speed over the 2012 results. The main challenge in this task is to design and implement a modem that modulates your digital data (the file on the SD-CARD) over the acoustic channel, transmits it through the loudspeakers of one of the smartphones and receives it via the microphone of the other one. Then, the received signal should be demodulated back to raw digital data. Therefore, the required skills for a good implementation includes knowledge of modulation and coding schemes, pulse-shaping and synchronization techniques. The references at the bottom of the page can provide you with some initial information for your task.
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Implement a system which is capable of transfering a file at 1kbits/sec using some simple technique e.g. FSK.
Push the data-rate as far as possible towards 32kbit/sec in real-time and 128kbit/sec in non real-time (as defined above). Try to double the data-rate until the target is met. Motivate and describe the methods used in each step. In real-time the system should be able to transmit file sizes up to at least 10kbytes.
The android assignment completed (given during the android lecture). The offline basic requirements should have been achieved.