Text

theses

The upcoming 5th generation mobile network architecture is envisioned to deploy massive Internet-of-Things (IoTs) devices with a variety of traffic patterns. These devices will often transmit short sporadic messages, which are not well suited to the connection-oriented modes associated with legacy 3GPP networks resulting in high service latency and excessive control overhead. This thesis presents the design of a low latency MAC (Medium Access Layer) / PHY (Physical Layer) protocol for emerging Internet of Things (IoT) devices that require low access delay. The goal is to operate in the same band as current LTE, thus not requiring any separate channel allocation, while maintaining backward compatibility with the current LTE system. The physical layer access is achieved using an underlay CDMA-based low power transmission scheme, which operates in the same frequency range as the LTE's uplink/downlink frequencies. The MAC layer is designed for low access latency by transmitting small sized data in a random access mode as it becomes available, eliminating the need to setup a connection.par A proof of concept prototype was developed to demonstrate the feasibility of the proposed design and the performance of the CDMA system and in presence of LTE. The CDMA based transmission was prototyped using the Software Defined Radio (SDR) platform (USRP B210/X310) and the code is written in C and C++. The LTE transmission is enabled using the OpenAirInterface (OAI) platform, which is an open sourced LTE implementation for Software Defined Radios. The performance of CDMA is studied with varying the spreading code length, message size, delay between transmitted packets, Signal to Noise Ratio (SNR). The CDMA based system is studied independently as well as in the presence of an ongoing LTE transmission. The results demonstrate that underlay burst CDMA transmissions for IoTs are capable of providing lower latency compared to LTE.The upcoming 5th generation mobile network architecture is envisioned to deploy massive Internet-of-Things (IoTs) devices with a variety of traffic patterns. These devices will often transmit short sporadic messages, which are not well suited to the connection-oriented modes associated with legacy 3GPP networks resulting in high service latency and excessive control overhead. This thesis presents the design of a low latency MAC (Medium Access Layer) / PHY (Physical Layer) protocol for emerging Internet of Things (IoT) devices that require low access delay. The goal is to operate in the same band as current LTE, thus not requiring any separate channel allocation, while maintaining backward compatibility with the current LTE system. The physical layer access is achieved using an underlay CDMA-based low power transmission scheme, which operates in the same frequency range as the LTE's uplink/downlink frequencies. The MAC layer is designed for low access latency by transmitting small sized data in a random access mode as it becomes available, eliminating the need to setup a connection.par A proof of concept prototype was developed to demonstrate the feasibility of the proposed design and the performance of the CDMA system and in presence of LTE. The CDMA based transmission was prototyped using the Software Defined Radio (SDR) platform (USRP B210/X310) and the code is written in C and C++. The LTE transmission is enabled using the OpenAirInterface (OAI) platform, which is an open sourced LTE implementation for Software Defined Radios. The performance of CDMA is studied with varying the spreading code length, message size, delay between transmitted packets, Signal to Noise Ratio (SNR). The CDMA based system is studied independently as well as in the presence of an ongoing LTE transmission. The results demonstrate that underlay burst CDMA transmissions for IoTs are capable of providing lower latency compared to LTE.

ETD_8313

M.S.

Includes bibliographical references

by Siddarth Mathur

doi:10.7282/T31G0QD9

ETD graduate

The author owns the copyright to this work.