Technical Information

Technical Specifications

Modulation	QPSK
Bit-to-Symbol Map	See the constellation to the right
Data Structure	16-bit unique word (UW) UW = 0 0 1 1 0 0 1 0 1 0 0 0 0 0 0 0 146 data bits See the frame structure below
Data Rate	21 27/73 kbits/sec
Composite Data Rate	24 kbits/sec
Pulse Shape	square-root raised cosine 100% excess bandwidth
Data Sequence	511-bit PN sequence download the MATLAB file containing this bit sequence
Radio Frequency (RF)	418 MHz

The bit-to-symbol assignments.

Minimum Performance Requirements

Achieve a bit error rate not greater than 0.0001 when the transmitter power is set to -10 dBm.

The Competition

The transmit and receive antennas will be provided by ACME Engineering. You do not have to design the antenna. The technical specifications of the antenna are described in ant-418-yg5-n_data_sheet.pdf.

At the competition, you will have to complete two tasks: demonstrate that your system meets the minimum specifications and explain your system design to the judges from ACME Engineering.

To demonstrate that your system meets the minimum specifications, the transmit power will be set to -10 dBm and the bit error rate will be measured using the bit error rate tester (BERT). Nothing more. Nothing less.

Judges from ACME engineering will interview each team, asking questions about the receiver (its performance, the design, trade-offs made, etc.). Each team will provide, before hand, a one page brochure highlighting the characteristics of their receiver. Each should also have available, details block diagrams, system flow diagrams, etc. to help answer the judges' questions.

The winner will be declared by the judges. The judging criteria are

Did the system meet the minimum performance requirements?

What does the BER curve look like? Do I believe the system is robust?

Is the design elegant?

Were the trade-offs smart?

Do I (a judge) understand how the system functions? Or is it a mysterious process?

Helpful Hints

Download a segment of C code that you should use to interface with the BERT.

Test Data Files

The test data files contain samples of the baseband I and Q outputs that your receiver front-end will be providing the A/D converters for the various scenarios described below. The sample rate is 48 ksamples/sec and each file represents approximately 2 seconds worth of data.

Name	Description
QPSK.mat	QPSK.mat contains samples of the baseband QPSK modulated signal with the 16-bit UW and 146 bits of the PN9 sequence. The data are stored in an L x 1 complex-valued vector where the real part contains samples of the I output and the imaginary part contains samples of the Q output.
QPSKrotate1.mat	QPSKrotate1.mat contains samples of the baseband QPSK modulated signal with the 16-bit UW and 146 bits of the PN9 sequence and a constant phase rotation. The data are stored in an L x 1 complex-valued vector where the real part contains samples of the I output and the imaginary part contains samples of the Q output.
QPSKrotate2.mat	PSK8_de_rotate2.mat contains samples of the baseband QPSK modulated signal with the 16-bit UW and 146 bits of the PN9 sequence and a small frequency offset. The data are stored in an L x 1 complex-valued vector where the real part contains samples of the I output and the imaginary part contains samples of the Q output.
QPSKSNR20dB.mat	QPSKSNR20dB.mat contains samples of the basebandQPSK modulated signal with the 16-bit UW and 146 bits of the PN9 sequence with noise such that Eb/No = 20 dB. No carrier phase synchronization is presumed. The data are stored in an L x 1 complex-valued vector where the real part contains samples of the I output and the imaginary part contains samples of the Q output.
QPSKSNR10dB.mat	QPSKSNR10dB.mat contains samples of the baseband QPSK modulated signal with the 16-bit UW and 146 bits of the PN9 sequence with noise such that Eb/No = 10 dB. No carrier phase synchronization is presumed. The data are stored in an L x 1 complex-valued vector where the real part contains samples of the I output and the imaginary part contains samples of the Q output.