Examples of Communication Systems/General Description of UMTS - Revision history

Guenter at 13:00, 13 March 2023

2023-03-13T13:00:39Z

Guenter at 12:57, 13 March 2023

2023-03-13T12:57:02Z

Hwang at 09:39, 8 March 2023

2023-03-08T09:39:39Z

Hwang at 09:37, 8 March 2023

2023-03-08T09:37:03Z

Hwang at 09:36, 8 March 2023

2023-03-08T09:36:37Z

Guenter at 13:21, 7 February 2023

2023-02-07T13:21:10Z

Guenter at 13:20, 7 February 2023

2023-02-07T13:20:35Z

Guenter at 16:43, 6 February 2023

2023-02-06T16:43:04Z

Guenter at 15:40, 6 February 2023

2023-02-06T15:40:55Z

Guenter at 10:20, 6 February 2023

2023-02-06T10:20:57Z

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 {{BlueBox|TEXT=
 $\text{Characteristics of time-selective fading:}$&nbsp;
-*In&nbsp; "time-selective fading",&nbsp;  a so-called&nbsp; '''&raquo;Doppler spread&laquo;'''&nbsp; $B_{\rm D}$&raquo; occurs,&nbsp; which is defined as the difference between the maximum and minimum Doppler frequencies occurring '''KORREKTUR: ohne "occurring"'''.
+*In&nbsp; "time-selective fading",&nbsp;  a so-called&nbsp; '''&raquo;Doppler spread&laquo;'''&nbsp; $B_{\rm D}$&raquo; occurs,&nbsp; which is defined as the difference between maximum and minimum Doppler frequencies.
 *The reciprocal of which is called the&nbsp; "correlation time"&nbsp;  $T_{\rm D} = {1}/{B_{\rm D} }$.&nbsp; In some literatures,&nbsp; this quantity is also referred to as&nbsp; "coherence time".&nbsp;  In UMTS,&nbsp; "time-selective fading"&nbsp; occurs whenever the correlation time&nbsp; $T_{\rm D}$&nbsp; is much smaller than the chip duration&nbsp; $T_{\rm C}$.}}

@@ Line 14: / Line 14: @@
 &rArr; &nbsp; In 2011&nbsp; $($when this chapter was conceived$)$&nbsp; about 200 million subscribers worldwide were using UMTS or similar third-generation mobile communications systems.
-&rArr; &nbsp; In 2022&nbsp; $($when this chapter was revised again as part of the English translation$)$&nbsp; a global report by the network equipment industry has identified more than  hundred operators&nbsp; that have either completed 3G switch-off alongside 2G switch-off, &nbsp; are planning to do so or are in the process of doing so,&nbsp; in order to use the spectrum this frees up for&nbsp; [[Mobile_Communications/General_Information_on_the_LTE_Mobile_Communications_Standard| "$\rm LTE$"]],&nbsp; '''KORREKTUR: Schrift?''' $\rm 5G$&nbsp; or technology-neutral.
+&rArr; &nbsp; In 2022&nbsp; $($when this chapter was revised again as part of the English translation$)$&nbsp; a global report by the network equipment industry has identified more than  hundred operators&nbsp; that have either completed 3G switch-off alongside 2G switch-off, &nbsp; are planning to do so or are in the process of doing so,&nbsp; in order to use the spectrum this frees up for&nbsp; [[Mobile_Communications/General_Information_on_the_LTE_Mobile_Communications_Standard| "LTE"]],&nbsp; "5G"&nbsp; or technology-neutral.
 *28 operators in 17 countries and territories have now completed 3G switch-off.
@@ Line 22: / Line 22: @@
 *Another 46 operators in 31 countries have 3G shutdowns planned for the very near future.
-*It is also interesting to note from this report that in some countries the UMTS switch-off is being pushed even harder than that of the 2G standard&nbsp; [[Examples_of_Communication_Systems/General_Description_of_GSM| "$\rm GSM$"]] '''KORREKTUR: Schrift?''',&nbsp; which is about ten years older.
+*It is also interesting to note from this report that in some countries the UMTS switch-off is being pushed even harder than that of the 2G standard&nbsp; [[Examples_of_Communication_Systems/General_Description_of_GSM| "GSM"]],&nbsp; which is about ten years older.

@@ Line 14: / Line 14: @@
 &rArr; &nbsp; In 2011&nbsp; $($when this chapter was conceived$)$&nbsp; about 200 million subscribers worldwide were using UMTS or similar third-generation mobile communications systems.
-&rArr; &nbsp; In 2022&nbsp; $($when this chapter was revised again as part of the English translation$)$&nbsp; a global report by the network equipment industry has identified more than  hundred operators&nbsp; that have either completed 3G switch-off alongside 2G switch-off, &nbsp; are planning to do so or are in the process of doing so,&nbsp; in order to use the spectrum this frees up for&nbsp; [[Mobile_Communications/General_Information_on_the_LTE_Mobile_Communications_Standard| "$\rm LTE$"]],&nbsp; $\rm 5G$&nbsp; or technology-neutral.
+&rArr; &nbsp; In 2022&nbsp; $($when this chapter was revised again as part of the English translation$)$&nbsp; a global report by the network equipment industry has identified more than  hundred operators&nbsp; that have either completed 3G switch-off alongside 2G switch-off, &nbsp; are planning to do so or are in the process of doing so,&nbsp; in order to use the spectrum this frees up for&nbsp; [[Mobile_Communications/General_Information_on_the_LTE_Mobile_Communications_Standard| "$\rm LTE$"]],&nbsp; '''KORREKTUR: Schrift?''' $\rm 5G$&nbsp; or technology-neutral.
 *28 operators in 17 countries and territories have now completed 3G switch-off.
@@ Line 22: / Line 22: @@
 *Another 46 operators in 31 countries have 3G shutdowns planned for the very near future.
-*It is also interesting to note from this report that in some countries the UMTS switch-off is being pushed even harder than that of the 2G standard&nbsp; [[Examples_of_Communication_Systems/General_Description_of_GSM| "$\rm GSM$"]],&nbsp; which is about ten years older.
+*It is also interesting to note from this report that in some countries the UMTS switch-off is being pushed even harder than that of the 2G standard&nbsp; [[Examples_of_Communication_Systems/General_Description_of_GSM| "$\rm GSM$"]] '''KORREKTUR: Schrift?''',&nbsp; which is about ten years older.

← Older revision		Revision as of 09:37, 8 March 2023
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	*In  "time-selective fading",  a so-called  '''»Doppler spread«'''  $B_{\rm D}$» occurs,  which is defined as the difference between the maximum and minimum Doppler frequencies occurring '''KORREKTUR: ohne "occurring"'''.		*In  "time-selective fading",  a so-called  '''»Doppler spread«'''  $B_{\rm D}$» occurs,  which is defined as the difference between the maximum and minimum Doppler frequencies occurring '''KORREKTUR: ohne "occurring"'''.

−	*The reciprocal of which is called the  "correlation time"  $T_{\rm D} = {1}/{B_{\rm D} }$.  In some literatures,  this quantity is also referred to as  "coherence time"&.nbsp; In UMTS,  "time-selective fading"  occurs whenever the correlation time  $T_{\rm D}$  is much smaller than the chip duration  $T_{\rm C}$.}}	+	*The reciprocal of which is called the  "correlation time"  $T_{\rm D} = {1}/{B_{\rm D} }$.  In some literatures,  this quantity is also referred to as  "coherence time".  In UMTS,  "time-selective fading"  occurs whenever the correlation time  $T_{\rm D}$  is much smaller than the chip duration  $T_{\rm C}$.}}

@@ Line 268: / Line 268: @@
 {{BlueBox|TEXT=
 $\text{Characteristics of time-selective fading:}$&nbsp;
-*In&nbsp; "time-selective fading",&nbsp;  a so-called&nbsp; '''&raquo;Doppler spread&laquo;'''&nbsp; $B_{\rm D}$&raquo; occurs,&nbsp; which is defined as the difference between the maximum and minimum Doppler frequencies occurring.
+*In&nbsp; "time-selective fading",&nbsp;  a so-called&nbsp; '''&raquo;Doppler spread&laquo;'''&nbsp; $B_{\rm D}$&raquo; occurs,&nbsp; which is defined as the difference between the maximum and minimum Doppler frequencies occurring '''KORREKTUR: ohne "occurring"'''.
 *The reciprocal of which is called the&nbsp; "correlation time"&nbsp;  $T_{\rm D} = {1}/{B_{\rm D} }$.&nbsp; In some literatures,&nbsp; this quantity is also referred to as&nbsp; "coherence time"&.nbsp;  In UMTS,&nbsp; "time-selective fading"&nbsp; occurs whenever the correlation time&nbsp; $T_{\rm D}$&nbsp; is much smaller than the chip duration&nbsp; $T_{\rm C}$.}}

@@ Line 29: / Line 29: @@
 This chapter includes in detail:
-#&raquo;UMTS as&laquo;&nbsp; a third-generation mobile communications system,
+#&raquo;UMTS&laquo;&nbsp;  as a third-generation mobile communications system,
 #the&nbsp; &raquo;services and security aspects&laquo;&nbsp; in UMTS,
 #the&nbsp; &raquo;UMTS network architecture&laquo;,

@@ Line 25: / Line 25: @@
-&rArr; &nbsp; We have chosen to keep this chapter in our&nbsp; $\rm LNTwww$&nbsp; despite this negative forecast,&nbsp; since understanding the underlying CDMA technology also facilitates students' understanding of other communications engineering problems. '''Korrektur''': Hier muss ich noch mit Kollegen reden.
+&rArr; &nbsp; We have chosen to keep this chapter in our&nbsp; $\rm LNTwww$&nbsp; despite this negative forecast,&nbsp; since understanding the underlying CDMA technology also facilitates students' understanding of other communications engineering problems.
 This chapter includes in detail:
@@ Line 276: / Line 276: @@
 $\text{Example 2:}$&nbsp;
 The left graph illustrates the difference between frequency-selective and non-frequency-selective fading:
-[[File:EN_Bei_T_4_1_S7_v3.png|right|frame|The red curves illustrate frequency-selective and time-selective fading '''Korrektur''']]
+[[File:EN_Bei_T_4_1_S7_v3.png|right|frame|The red curves illustrate frequency-selective and time-selective fading]]
 #Shown in this graph is the logarithm power transfer function&nbsp; $\vert H_{\rm K}(f,\ t)\vert ^2$&nbsp; of the channel at a fixed time&nbsp; $t$.
 #While non-frequency-selective fading is plotted in blue with&nbsp; $-5 \ \rm dB$&nbsp;, the red curve shows an example of frequency-selective fading.
@@ Line 325: / Line 325: @@
 #&nbsp;encryption and authentication of security data during transmission,
 #&nbsp;mechanisms for updating the security features.
-[[File:EN_Bei_T_4_1_S10_v2.png|right|frame|Compilation of security measures in UMTS '''Korrektur''']]
+[[File:EN_Bei_T_4_1_S10_v2.png|right|frame|Compilation of security measures in UMTS]]

@@ Line 201: / Line 201: @@
 In the UMTS radio channel,&nbsp; in addition to interference from other subscribers and noise,&nbsp; a number of unpredictable,&nbsp; interfering and distorting effects occur,&nbsp; which also change over time.
-[[File:P_ID1529__Bei_T_4_1_S5a_v2.png|right|frame|Scenario with multipath propagation]]
+[[File:EN_Mob_T1_1_S1.png|right|frame|Example for a mobile radio scenario|class=fit]]
 &rArr; &nbsp; Due to reflections as well as scattering and diffraction from objects,&nbsp;  the transmitted signal experiences&nbsp; '''&raquo;multipath propagation&laquo;'''.