1. MAC Protocol Implementation on Atmel AVR for Underwater Communication by Shaolin Peng CSC 714 Real Time Computer Systems

2. Aloha Protocol Atmega168 MACA Protocol Small & Sparse Network Small Packet Size Development Platform: STK500 AVR Studio

3. Problem List P1: Debugging Instrument  Set up UART communication with the HyperTerminal on PC  Connect two boards using wire as a start P2: Starvation  Wait only after sending, not after receiving P3: Flexible Length Packet Receiving  Receive the first two bytes, decode and decide P4: CRC Consideration  4 bits -> 8 bits (x^8 + x^2 + x + 1)

4. Problem List 2 P5: Random Number Generator  ADC or Timer Counter P6: No response problem  Set maximum retries number P7: Hardware Limitation  Compile different files using different optimization levels E.g. -O3 for Goertzel algorithm (critical path) -Os for the other files Text data bss total 14986 302 141 15429 (different optimization levels) 16380 338 109 16827 (same optimization level)

5. Lake Raleigh Experimental Setup Throughput= Successfully received packets Total packets sent out

6. Results Indoors  Aloha: 27.2%  MACA: 23.8% Outdoors  Aloha: 8.1%  MACA: 8.2% Compare with MACA  During the testing time, Aloha received almost twice data than MACA

7. Thanks! Questions?