Cody LovejoyRamsey DoanyKyle Jones Ingram School of Engineering Texas State University
PROBLEM STATEMENT The International Space Station (ISS) Power Consumption Current RFID Inventory System Inefficient Wasteful
WHAT IS RFID? Radio Frequency Identification Credit Cards Key Cards Inventory
Passive RLC Circuit Induction Frequency Antenna Microchip Data (128 bit) Random Number Generator Handle Response Delay Time RFID SYSTEM TagReader Antenna Transceiver Computer/Software Modulation /Coding Demodulation /Decoding
CURRENT OPERATION (TDM) Tag Power-Up/Search Query Load 2 Q -1 Bit RNG Decrement/Search Query Handle Number ACK Tag Data ACK/Tag Power-Down
PROPOSAL TDM CDMA/DSSS Conform to Class I Gen. II Specs 75% reduction in power consumption Read 5 tags simultaneously Alien ALR RFID Development System
THE BASICS Decrease bit periodIncrease transmission speed Increase transmission speedIncrease bandwidth occupied by bit
CDMA/DSSS Code Division Multiple Access (CDMA) Multiplexing Multiple users occupy channel simultaneously Orthogonal spreading codes Direct Sequence Spread Spectrum Spreading signal bandwidth Increase transmission speed Bit redundancy
OPERATION 1.Transmitter receives user data 2.Data clocked into XOR circuit 3.Spreading code n times longer than user data sequence clocked into same circuit n times as fast 4.User data signal effectively spread over bandwidth n times as wide as original data 5.Receiver XOR signal with same spreading code to de-spread (decode) signal
CDMA-BASED RFID SYSTEM Tag Power-Up/Query Tag Data Single “beckoning” signal All tags respond simultaneously (128 bit EPC data) Reader receives summation of all tag transmissions Reader demodulates/decodes signal
1 transmission (any number of tags) 98.5% less power consumption “Brute force” method At least 69 transmissions (5 tags, assuming no collisions) Reader constantly scanning SUPERIORITY OF CDMA- BASED SYSTEM TDM-Based SystemCDMA-Based System
DESIGN POSSIBILITIES 1.Physical implementation of CDMA/DSSS Disable RNG (or set all RNG to select same value) EPC data encoded according to spreading code 2.Standard Protocol/Time Shift Use current system to read 5 tags Record electrical response Mathematically time shift signals Demodulate/decode signal 3.Simulation of entire process
TEST PLAN Trace and display single “beckoning” signal Trace and display summation of tag transmission (at receiver) Display demodulated and decoded data on PC
CONSTRAINTS Manufacturability Economies of scale BUDGET $600 All RFID hardware and testing equipment provided by Texas State University No expected additional expenditures
WORK BREAKDOWN STRUCTURE
TIMELINE JanFebMarAprMayJunJulAugSepOctNovDec 2015 Read /Write Tags (Current System) Select MUX Technique Characterize Current Output Design Tag Mods Mod Tags Begin Software Design Implement Software 1 Tag Functioning 3 Tags Functioning 5 Tag System Complete Begin Testing
AT OUR BOOTH Alien ALR RFID Development System Images of acquired transmission signals Mathematical proof of claims