# <center> Pre-Intern Notes </center> **Topic: Random Access Procedure for 802.11ax** Bariq S. Firmansyah Institut Teknologi Bandung [email](mailto://bariqsufif@gmail.com) ###### tags: `NTUST-RESEARCH` --- ***[5G] Research on Random Access: A. 3GPP LTE/5G NR; B. IEEE 802.11ax (Supervisor Ray: I~III should be done before April)*** *Goal: (A) Performance evaluation of the random access channel for 4G/5G networks (B) Performance evaluation of the Uplink OFDMA Random Access (UORA) in 802.11ax* ## Slotted ALOHA >**Week 1**: -February 28, 2020 :::success [slotted aloha note](https://hackmd.io/@bariqsufif/slotted) ::: :::info - [x] Study the background material of Slotted Aloha in book - [x] Read this https://hackmd.io/@Ting-An/SycM0lvDS - [x] Create the simulation of Slotted ALOHA - [x] Draw a figure showing simulation and analytical results. X: Offered load, Y: Throughput - [x] Compare the analytical and simulation result ::: ## Multichannel Slotted ALOHA >**Week 2&3**: March 9, 2020 :::success [multichannel slotted aloha note](https://hackmd.io/@bariqsufif/multichannelslotted) ::: :::info - [x] Study the background material of Multichannel Slotted Aloha in book - [x] Create the simulation of Multichannel Slotted ALOHA - [x] Draw a figure showing simulation and analytical results. X: Offered load, Y: Throughput - [x] Compare the analytical and simulation result ::: ## One-Shot Random Access >**Week 4-5**: March 23, 2020 :::success [one-shot random access mote](https://hackmd.io/@bariqsufif/oneshot) ::: :::info - [x] Duplicate the result for Dr. Wei’s paper published on IEEE Comm. Ltr. (Ref: https://bit.ly/38pigLK) ::: ## IEEE 802.11ax >June 6, 2020- :::success [802.11ax summary](https://hackmd.io/@bariqsufif/11axsummary) ::: :::info - [x] IV-B.1. Selected Paper: [A Tutorial on IEEE 802.11ax High Efficiency WLANs](https://ieeexplore.ieee.org/abstract/document/8468986) - [x] IV-B.2. Selected Paper: [Performance analysis of IEEE 802.11ax UL OFDMA-based random access mechanism](https://ieeexplore.ieee.org/document/8254054) - [x] IV-B.3. Selected Paper: [Survey and Performance Evaluation of the Upcoming Next Generation WLAN Standard - IEEE 802.11ax](https://arxiv.org/pdf/1806.05908.pdf) :::
Last changed by  
 
bariq firmansyah
643

Read more

#Slotted ALOHA

Topic: 5G Random Access Procedure Bariq Sufi Firmansyah Institut Teknologi Bandung bariqsufif@gmail.com Background ::: spoiler Click to view the background knowledge of Pure ALOHA, you can skip this if you already understand The network is constructed such that each station is coupled to a single passive channel, for example a coaxial cable In normal operation packets are transmitted without error from one station to another and each packet is acknowledged If two stations try to transmit at the same time, then the signals interfere and an error is detected by the receiving station and no acknowledgement is sent

7/17/2020
2020/7/1 Report

Why do I do this job? Because I want to analyze the performance of UORA in 802.11 ax What do I want to do? Continue writing the timing diagram, flow chart and performance evaluation Sum of the job I analyze the simulation result and compare it to the analytical model Expected Outcome Finish writing the timing diagram, flow chart and performance evaluation Intro UL OFDMA is the multi-user variant of the OFDM whereby assigning subsets of subcarriers, called resource unit (RU), to different users allows simultaneous transmissions of data, control, and management frames from several users so it can serve more users at the same time The MU UL transmissions are solicited by the AP in a new control frame called trigger frame (TF). A STA that is the intended receiver of the TF responds with an HE trigger-based PPDU UL OFDMA RA is a mechanism that enables a STA to transmit an UL physical layer protocol data unit (PPDU) in an RU access under UL OFDMA even if it has not been explicitly addressed. A STA uses a random back-off procedure before it randomly selects any one of the multiple RUs assigned for random access for its UL transmission

7/1/2020
#One-Shot Random Access

Topic: 5G Random Access Procedure Bariq Sufi Firmansyah Institut Teknologi Bandung bariqsufif@gmail.com Background One-Shot Random Access: Analytical Model In this system, time is divided into fix-length ‘access cycle.’ Each access cycle contains $N$ RAOs. All of the $M$ devices transmit their first random-access attempts at a randomly chosen RAO in the first access cycle. The collided devices immediately re-transmit their random-access attempts in the next access cycle. A total of $I_{max}$ access cycles are reserved.

7/1/2020
Slotted ALOHA

:::success [x] Step 1: Background knowledge (with text and figures) [x] Step 2: System model (I/P parameters, system architecture and timing diagram) [x]Step 3a: Specify the constant [ ]Step 3b: Draw a timing diagram showing the transmission behavior of a STA [x] Step 4: Simulator (Data structure, flowchart) [ ]Step 5: Verification of values generated from the simulator and Step 3b [x]Step 6: Simulation results

5/28/2020
Read more from bariq firmansyah
Published on HackMD