Stratospheric Broadband

YORK HAP WEEK

Source(random byte)

FEC

encoderRS(255,239)

CAZAC

ModulatorsQPSK

16QAM

64QAM

Symbol

mapper

Frame

composing

Raised

cosine

transmit

filter

Quantizer

FEC

decoderDemodulators

CAZAC

processing

SinkSymbol

demapper

Frame

decomposing

Raised

cosine

receive

filter

AGC

Channel

AWGN

or

HAP

ACM

switch

DSP implementation of ACM proceduresDSP implementation of ACM proceduresDSP implementation of ACM proceduresDSP implementation of ACM procedures

IEEE 802.16 BWA standard

Working Environment

DSP implementation

Evaluation of ACM Procedures

Scope of IEEE 802 standards Adaptive physical layerConceptual block diagram of transmitter and receiver

TI TMS320C6713 DSK board•225 MHz system clock

•Processor

•32-bit floating-point

•8 functional units

•Onboard stereo audio codec (AIC23)

•DAC/ADC

•Variable sample rate (from 8 to 96 kHz)

•Supported word lengths (16, 20, 24 and

32 bits)

MATLAB/Simulink R2006a•Signal Processing Toolbox & Blockset

•Communications Toolbox & Blockset

•Real-Time Workshop

•Real-Time Workshop Embedded Coder

•Embedded Target for TI C6000 DSP

•Link for Code Composer Studio

TI Code Composer Studio v3.1•Analysis Toolkit v1.3

M. Smolnikar, T. Javornik, M. Mohorcic

Jozef Stefan Institute, Ljubljana, Slovenia

Implemented functionalities•QPSK, 16-QAM and 64-QAM modulators and

demodulators

•Reed-Solomon FEC encoder and decoder

•Frame composer and decomposer

•CAZAC sequence processing

•Transmit and receive square-root raised cosine

pulse shaping filters

•Automatic gain control (AGC)

•Adaptive coding and modulation (ACM) switch

Block scheme of the ACM model

RECEIVER

SS – in the case of downlink

BS – in the case of uplink

RF channel

Random-

ization

FEC

encoder

Preamble

prepend

Symbol

mapper

Baseband

pulse

shaping

filter

Modulator

and

physical

interface

TX data

Derandom-

ization

FEC

decoder

Symbol

demapper

Matched

filter and

equalizer

Physical

interface

and

demodulator

RX data

TRANSMITTER

BS – in the case of downlink

SS – in the case of uplink