1 / 9

Wireless LAN 802.11

Wireless LAN 802.11. Haithem AL-Balawi. Outline. Background Design Consideration and Assumptions Results and Findings Questions. Background. IEEE 802.11  Defines the Medium Access Control (MAC) and Physical Layer (PHY) specified for wireless connection. Background.

ernst
Download Presentation

Wireless LAN 802.11

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Wireless LAN802.11 Haithem AL-Balawi

  2. Outline • Background • Design Consideration and Assumptions • Results and Findings • Questions

  3. Background • IEEE 802.11  Defines the Medium Access Control (MAC) and Physical Layer (PHY) specified for wireless connection

  4. Background • Components of the IEEE 802.11

  5. Network PCF MAC DCF PHY Background • MAC Overview • Distributed Coordination Function (DCF) is the Media Access Function of 802.11 MAC and used for contention services • Point Coordination Function (PCF) is used for contention free services

  6. Background • DCF Operation

  7. Design Consideration and Assumptions • STAs are transmitting randomly through a Bernoulli distribution • Hidden STAs are ignored • CW is randomly and equally likely selected between [0 CW] • STA will transmit whenever it’s P_STA >P_Tx

  8. for i=1:length(Time_Access) if (Time_Access(1,i)==0) elseif (Ready_Tx >1) N_Colision=N_Colision+1; for z=1:length(Ready_STA) N_Backoff(1,Ready_STA(z))= randint(1,1,[1 2^randint(1,1,CW-1)]); end end clear all STA=50; %Number of Terminals P_Tx=0.5; for N=1:STA data_Tx=10; %Transmitted data size IFS=2; %Interframe Space size %N_Success=zeros(1,N); % Number of successful trials CW=5; %Contention Wendow Time_Access=zeros(1,100000); N_Backoff=zeros(1,N); %Backoff Counter for each STA N_Count=zeros(1,N); IFS_Count=0; Idle=0; N_Colision=0; Ready_STA=0; • Algorithm [min_N,indx_N]=min(N_Backoff); Ready_Tx=0; y=1; if (min_N ==0) %Backoff timer is "0" if not non of the STAs are ready to transmit for a=1:N if (N_Backoff(1,a) ==0) if (P_STA(1,a) >= P_Tx) Ready_STA(y)=a; y=y+1; Ready_Tx=Ready_Tx+1; end end end if (Ready_Tx ==1) Time_Access(1,i:i+data_Tx-1)=indx_N; N_Backoff(1,indx_N)=randint(1,1,[1 2^randint(1,1,CW-1)]); Time_Access(1,i+data_Tx:i+data_Tx+IFS-1)=-1; else N_Backoff=N_Backoff-1; end

  9. Results and Findings • System Behavior for Random Access • the throughput is high for large number of STAs (65% for 50 STA) • the number of collided attempts is almost negligible • by using longer data packet size throughput improves

More Related