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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><!--Converted with LaTeX2HTML 96.1 (Feb 5, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds --><HTML><HEAD><TITLE>TDMA Slot Structure</TITLE><META NAME="description" CONTENT="TDMA Slot Structure"><META NAME="keywords" CONTENT="gprs"><META NAME="resource-type" CONTENT="document"><META NAME="distribution" CONTENT="global"><LINK REL=STYLESHEET HREF="gprs.css"></HEAD><BODY LANG="EN"> <A NAME="tex2html166" HREF="node6.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="http://cbl.leeds.ac.uk/nikos/figs/next_motif.gif"></A> <A NAME="tex2html164" HREF="node3.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="http://cbl.leeds.ac.uk/nikos/figs/up_motif.gif"></A> <A NAME="tex2html158" HREF="node4.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="http://cbl.leeds.ac.uk/nikos/figs/previous_motif.gif"></A> <BR><B> Next:</B> <A NAME="tex2html167" HREF="node6.html">Timing Advance</A><B>Up:</B> <A NAME="tex2html165" HREF="node3.html">MAC Implementation Details</A><B> Previous:</B> <A NAME="tex2html159" HREF="node4.html">Channels</A><BR> <P><H2><A NAME="SECTION00122000000000000000">TDMA Slot Structure</A></H2><P>Every TDMA frame has 8 slots (defined as SLOTS_PER_FRAME). Slot durationis set as 577 microseconds. We transmit 50 bytes ie one (simulated) RLCPDU, in each slot. This models the transmission of one GPRS Radio Block(RB) (of size 200 bytes) over four slots in consecutive frames. Forpackets smaller than the size of an RLC PDU (ex <EM>rlc_acks</EM> or <EM>ll_acks</EM>), the packet transmission time is taken as <EM>packet_size/transmission_rate</EM>.<P>We use <EM>Up_Slot_Gprs_Timer</EM> and <EM>Down_Slot_Gprs_Timer</EM> tosignal the start and end of each slot on the uplink and downlinkrespectively, and the processing is handled by the <EM>upslotHandler()</EM>and <EM>downslotHandler()</EM> respectively.<P>The <EM>upslotHandler()</EM> checks whether any MS has a packet to transmitin the current upslot. If it does, the packet is passed onto <EM>tx_onto_PHY()</EM> that starts the `transmission' of the packet. Similarlythe <EM>downslotHandler()</EM> checks at the BS.<P><BR> <HR><UL> <LI> <A NAME="tex2html168" HREF="node6.html#SECTION00122100000000000000">Timing Advance</A></UL><BR> <HR><P><ADDRESS><I>Richa Jain (96D07007) <BR>Tue Jul 24 22:29:53 IST 2001</I></ADDRESS></BODY></HTML>?? 快捷鍵說明
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