UplinkGrant-free SCMA transmissions with active user detection and channel estimation | |
| Author | Su Pyae Sone |
| Call Number | AIT Thesis no.TC-18-01 |
| Subject(s) | Internet of things Coding theory Orthogonal frequency division multiplexing Computer algorithms |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Telecommunications |
| Publisher | Asian Institute of Technology |
| Abstract | People nowadays are interested in Internet of Things (IoT) and connecting them globally. One possible solution is to add IoT devices to services provided by an existing cellular net-work. All of the IoT devices should be assigned to the network but only a few will be active at the same time. Therefore, several researchers have been trying to overload the users in the network, and non-orthogonal multiple access (NOMA) is preferred over orthogonal frequency division multiple access (OFDMA). Among several NOMA schemes, sparse code multiple access (SCMA) is recognized for having the shaping gain of a codebook and being compatible with the near-optimal detection using the message passing algorithm (MPA). In an SCMA system, the receiver needs to detect which users are active at any given time and estimate their channels. Therefore, detection of active users and channel estimation are crucial parts in such a system. Different types of pilots to detect active users and estimate the channels have been proposed by several researchers. Most of their pilots are long and their detection algorithms are complex. In this thesis, active sub-carrier based orthogonal pilots whose lengths are short are proposed for active user detection and channel estimation. Moreover, theoretically calculated detection thresholds is applied for controlling false alarm and miss detection probabilities. Compared to previous results, the proposed pilot scheme can also be applied for larger SCMA systems with higher numbers of sub-carriers and users. |
| Year | 2018 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Attaphongse Taparugssanagorn;Poompat Saengudomlert; |
| Examination Committee(s) | Teerapat Sanguankotchakorn;Dailey, Matthew N.; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) -- Asian Insitute of Technology, 2018 |