Turbo Code with Modified LLR and Performance Analysis for Bluetooth Packets in Indoor Environments

Abstract

Most of the restrictions in indoor environments do not exist for outdoor sites. The main limitations for indoors are the attenuation of walls and the multipath fading effects. The signal propagation is limited by the standard free space path loss in outdoor environments or free space. The loss in free space is usually equal to the range squared whereas the loss exponent for indoors is more like the 4th power. This study investigates the performance of turbo codes with modified Maximum-A-Posteriori (MAP) decoding algorithm for Bluetooth data packets in indoor environments over the frequency selective Rayleigh fading channels; which are also called as indoor wireless communication channels. In order to reduce the computational complexity of turbo decoders, MAP algorithm is modified in this study. Bit error rate (BER) versus energy of bit-to-noise ratio (E b /N o ) of modified MAP algorithms for Bluetooth data packets at 2.4 GHz industrial-scientific-medical (ISM) band are evaluated by means of computer simulations. Thus, modified logarithmic likelihood ratio (LLR) method can significantly reduce the computational complexity of the MAP algorithm. Furthermore, the performances of different types of forward error correction (FEC) coding for Bluetooth data packets are compared in the study.

Low-Complexity Error Correction for ISO/IEC/IEEE 21451-5 Sensor and Actuator Networks

“…As a matter of fact, turbo codes are proved to be effective solutions for WiFi [26], Bluetooth [27]- [29], Zigbee [30], and 6LowPAN [31], which can be employed in 21451-5. On the other hand, turbo codes are applied widely in traditional WSNs [11]- [17].…”