Background information - Revision history

Nikunj at 10:40, 16 October 2007

2007-10-16T10:40:24Z

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Nikunj: /* '''OFDMA frame structure''' */

2007-09-26T04:29:31Z

‎'''OFDMA frame structure'''

Nikunj: /* Ranging */

2007-09-26T04:08:03Z

‎Ranging

Madhuri: /* Network entry and initialization */

2007-09-24T07:48:51Z

‎Network entry and initialization

Madhuri: /* '''OFDMA frame structure''' */

2007-09-24T07:48:01Z

‎'''OFDMA frame structure'''

Madhuri: /* '''Up link zone''' */

2007-09-24T07:46:47Z

‎'''Up link zone'''

Madhuri: /* Single carrier approach & Multi carrier approach */

2007-09-24T07:45:58Z

‎Single carrier approach & Multi carrier approach

Madhuri: /* '''Down link zone''' */

2007-09-24T07:45:08Z

‎'''Down link zone'''

Madhuri: /* Difference between FDM and OFDMA */

2007-09-24T07:44:12Z

‎Difference between FDM and OFDMA

Madhuri: /* Block Diagram */

2007-09-24T07:38:23Z

‎Block Diagram

@@ Line 130: / Line 130: @@
 =='''OFDMA frame structure'''==
-[[Image:frame structure.jpeg|center|600px|thumb| <font size = "3">'''OFDMA frame structure'''</font>]]
+[[Image:frame structure1.jpeg|center|600px|thumb| <font size = "3">'''OFDMA frame structure'''</font>]]
 =='''Advantages'''==

← Older revision		Revision as of 04:08, 26 September 2007
Line 234:		Line 234:

	[[Image:Ranging Procedure.jpg\|thumb\|center\|800 px\|<font size = "3">'''Ranging pocedure'''</font>]]		[[Image:Ranging Procedure.jpg\|thumb\|center\|800 px\|<font size = "3">'''Ranging pocedure'''</font>]]
−
−	~~'''Ranging with bandwidth request:'''~~

	==Parameters==		==Parameters==

@@ Line 215: / Line 215: @@
 [[Image:Service establishment procedure of OFDMA TDD WMAN (including QoS negotiation).jpeg|center|800 px|thumb| [http://www.wimaxforum.org/technology/WiMAX_IMT_2000/8F_1359.doc <font size = "3">'''Service establishment procedure of OFDMA TDD WMAN(including QoS negotiation)'''</font>]]]
-[[Image:Network Entry Process.jpg|center|800 px|thumb| [http://inst.eecs.berkeley.edu/~ee122/sp07/80216.pdf <font size = "3">'''Network Entry Process'''</font>]]]
+[[Image:Network Entry Process.jpg|center|600 px|thumb| [http://inst.eecs.berkeley.edu/~ee122/sp07/80216.pdf <font size = "3">'''Network Entry Process'''</font>]]]
-[[Image:Signalling dia for Authentication.jpg|center|800 px|thumb|<font size = "3">'''Signalling diagram for Authentication'''</font>]]
+[[Image:Signalling dia for Authentication.jpg|center|600 px|thumb|<font size = "3">'''Signalling diagram for Authentication'''</font>]]
 ===Ranging===

@@ Line 130: / Line 130: @@
 =='''OFDMA frame structure'''==
-[[Image:frame structure.jpeg|center|800px|thumb| <font size = "3">'''OFDMA frame structure'''</font>]]
+[[Image:frame structure.jpeg|center|600px|thumb| <font size = "3">'''OFDMA frame structure'''</font>]]
 =='''Advantages'''==

@@ Line 113: / Line 113: @@
 *Example of mapping OFDMA slots to subchannels and symbols in the uplink
-[[Image:Example of mapping OFDMA slots to subchannels and symbols in the uplink.jpeg|center|800px|thumb|  <font size = "3">'''Up link zone'''</font>]]
+[[Image:Example of mapping OFDMA slots to subchannels and symbols in the uplink.jpeg|center|600px|thumb|  <font size = "3">'''Up link zone'''</font>]]
 ===Steps for OFDMA data mapping===
 * The UL mapping consists of two steps. In the first step, the OFDMA slots allocated to each burst are selected. In the second step, the allocated slots are mapped.

@@ Line 68: / Line 68: @@
 ===Single carrier approach & Multi carrier approach===
-[[Image:single carrier approch.jpg|center|800px|thumb| [http://www.ert.rwth-aachen.de/Projekte/Theo/OFDM/node4.html <font size = "3">'''Single carrier approch'''</font>]]]
+[[Image:single carrier approch.jpg|center|600px|thumb| [http://www.ert.rwth-aachen.de/Projekte/Theo/OFDM/node4.html <font size = "3">'''Single carrier approch'''</font>]]]
 * As per above figure the general structure of a single carrier transmission system is depicted. The transmitted symbols are pulse formed by a transmitter filter. After passing the multipath channel in the receiver a filter matched to the channel is used to maximize signal to noise ratio a the device used to extract the data.
@@ Line 74: / Line 74: @@
 * Figure below shows the general structure of a multicarrier system.
-[[Image:multi carrier approch.jpg|center|800px|thumb| [http://www.ert.rwth-aachen.de/Projekte/Theo/OFDM/node5.html <font size = "3">'''Multi carrier approch'''</font>]]]
+[[Image:multi carrier approch.jpg|center|600px|thumb| [http://www.ert.rwth-aachen.de/Projekte/Theo/OFDM/node5.html <font size = "3">'''Multi carrier approch'''</font>]]]
 *One key principle of OFDM is that since low symbol rate modulation schemes (i.e. where the symbols are relatively long compared to the channel time characteristics) suffer less from intersymbol interference caused by multipath, it is advantageous to transmit a number of low-rate streams in parallel instead of a single high-rate stream. Since the duration of each symbol is long, it is feasible to insert a guard interval between the OFDM symbols, thus eliminating the intersymbol interference. The guard interval also eliminates the need for a pulse-shaping filter, and it reduces the sensitivity to time synchronization problems.

@@ Line 103: / Line 103: @@
 * Example of mapping OFDMA slots to subchannels and symbols in the down link(in PUSC mode)
-[[Image:Example of mapping OFDMA slots to sub channels and symbols in the down link.jpeg|center|800px|thumb|<font size = "3">'''Down link zone'''</font>]]
+[[Image:Example of mapping OFDMA slots to sub channels and symbols in the down link.jpeg|center|600px|thumb|<font size = "3">'''Down link zone'''</font>]]
 ===Steps of OFDMA data mapping:===

@@ Line 79: / Line 79: @@
 ==Difference between FDM and OFDMA==
-[[Image:Diff_wave_form.jpg|center|800px|thumb|  [http://images.google.co.in/imgres?imgurl=http://www.mprg.org/research/OFDM/images/fig1.gif&imgrefurl=http://www.mprg.org/research/OFDM/index.html&h=208&w=383&sz=5&hl=en&start=9&um=1&tbnid=_EbqcjAiE_s27M:&tbnh=67&tbnw=123&prev=/images%3Fq%3DOFDM%2B%252B%2BFDm%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG  <font size = "2">'''Difference between FDM and OFDMA'''</font>]]]
+[[Image:Diff_wave_form.jpg|center|600px|thumb|  [http://images.google.co.in/imgres?imgurl=http://www.mprg.org/research/OFDM/images/fig1.gif&imgrefurl=http://www.mprg.org/research/OFDM/index.html&h=208&w=383&sz=5&hl=en&start=9&um=1&tbnid=_EbqcjAiE_s27M:&tbnh=67&tbnw=123&prev=/images%3Fq%3DOFDM%2B%252B%2BFDm%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG  <font size = "2">'''Difference between FDM and OFDMA'''</font>]]]
 [[Image:OFDMA Multi User Access.jpg|center|800px|thumb|<font size = "3">'''OFDMA Multi User Access'''</font>]]
@@ Line 88: / Line 88: @@
 *Orthogonal Frequency Division Multiplexing (OFDM) is a method that allows to transmit high data rates over extremely hostile channels at a comparable low complexity. OFDM has been chosen as the transmission method for the European radio (DAB) and TV (DVB-T) standard. Due to its numerous advantages it is under Discussion for future broadband application such as wireless ATM as well.
-[[Image:guard_band.jpg|center|800px|thumb| [http://en.wikipedia.org/wiki/OFDMA  <font size = "3">'''Subcarrier allocation'''</font>]]]
+[[Image:guard_band.jpg|center|600px|thumb| [http://en.wikipedia.org/wiki/OFDMA  <font size = "3">'''Subcarrier allocation'''</font>]]]
 ==Definition of slot==

@@ Line 4: / Line 4: @@
 ==Block Diagram==
-[[Image:block_diagram.gif|center|800px|thumb|Block Diagram]]
+[[Image:block_diagram.gif|center|600px|thumb|Block Diagram]]
 *'''Data:'''