Examples of Communication Systems/Telecommunications Aspects of UMTS - Revision history

Guenter at 16:15, 20 April 2023

2023-04-20T16:15:42Z

Guenter at 17:16, 25 March 2023

2023-03-25T17:16:34Z

Guenter at 15:07, 25 March 2023

2023-03-25T15:07:01Z

Guenter at 13:23, 13 March 2023

2023-03-13T13:23:04Z

Hwang at 10:43, 8 March 2023

2023-03-08T10:43:22Z

Hwang at 10:42, 8 March 2023

2023-03-08T10:42:03Z

Hwang at 10:41, 8 March 2023

2023-03-08T10:41:37Z

Hwang at 10:39, 8 March 2023

2023-03-08T10:39:21Z

Hwang at 10:28, 8 March 2023

2023-03-08T10:28:37Z

Hwang at 10:26, 8 March 2023

2023-03-08T10:26:36Z

@@ Line 446: / Line 446: @@
 The ratio between the signal power and the interference power is used as the controlled variable for power control in UMTS.&nbsp; There are differences between the&nbsp; "frequency division duplex"&nbsp; $\rm (FDD)$&nbsp; and the&nbsp; "time division duplex"&nbsp; $\rm (TDD)$&nbsp; modes.
-[[File:EN_Bei_T_4_3_S10a.png|right|frame|Power control in the FDD mode '''KORREKTUR: transmit power''']]
+[[File:EN_Bei_T_4_3_S10a_neu.png|right|frame|Power control in the FDD mode]]
 We take a closer look at the FDD power control.&nbsp; In the diagram you can see two different control loops:
 *The&nbsp; &raquo;'''inner control loop'''&laquo;&nbsp; controls the transmitter power based on time slots,&nbsp; where one power command is transmitted in each time slot.&nbsp;

@@ Line 486: / Line 486: @@
 {{GraueBox|TEXT=
-[[File:EN_Bei_T_4_3_S9_v2.png|right|frame|Budget for a voice transmission channel '''KORREKTUR: fault''']]
+[[File:EN_Bei_T_4_3_S9_v222.png|right|frame|Budget for a voice transmission channel]]
 $\text{Example 7:}$&nbsp;
 The calculation of the link budget is illustrated using the example of a voice transmission channel in the UMTS downlink.&nbsp; Regarding the exemplary numerical values,&nbsp; it should be noted:

@@ Line 490: / Line 490: @@
 The calculation of the link budget is illustrated using the example of a voice transmission channel in the UMTS downlink.&nbsp; Regarding the exemplary numerical values,&nbsp; it should be noted:
 #The transmitted power is&nbsp; $P_{\rm S} =19$&nbsp; dBm,&nbsp; which corresponds to approx.&nbsp; $79$&nbsp; mW.&nbsp; <br>Here,&nbsp; the antenna loss is considered to be&nbsp; $2$&nbsp; dB.
-#The noise power&nbsp; $P_{\rm R} = 5 \cdot 10^{-11}$&nbsp;  mW &nbsp; &rArr; &nbsp; $P_{\rm R} = -103$&nbsp;  dBm &nbsp; <br>product of UMTS bandwidth and noise power density.
+#The noise power&nbsp; $P_{\rm N} = 5 \cdot 10^{-11}$&nbsp;  mW &nbsp; &rArr; &nbsp; $P_{\rm N} = -103$&nbsp;  dBm &nbsp; <br>product of UMTS bandwidth and noise power density.
 #The interference power is&nbsp; $P_{\rm I} = -99$&nbsp; dBm&nbsp; corresponding to&nbsp; $1.25 \cdot 10^{-10}$&nbsp;  mW.
-#This gives the total interference power&nbsp; $P_{\rm R+I} = P_{\rm R} + P_{\rm I} = 1.25 \cdot 10^{-10}$&nbsp; mW &nbsp; &rArr; &nbsp; $P_{\rm R+I} =- 97.5$&nbsp;  dBm.
+#This gives the total interference power&nbsp; $P_{\rm N+I} = P_{\rm N} + P_{\rm I} = 1.25 \cdot 10^{-10}$&nbsp; mW &nbsp; &rArr; &nbsp; $P_{\rm N+I} =- 97.5$&nbsp;  dBm.
 #The antenna sensitivity results in $-97.5 - 27 + 5 - 17 + 3.5 = - 133$&nbsp; dBm.&nbsp; <br>A large negative value here is&nbsp; "good".
 #Maximum allowable path loss should be as large as possible.&nbsp; Here&nbsp; $19 - (-133) = 152$&nbsp; dB.
 #The&nbsp; '''link budget'''&nbsp; includes the margin for fading and the handover gain,&nbsp; in the example:&nbsp;  $140$&nbsp; dB.
-#The&nbsp; '''maximum cell radius'''&nbsp; can be determined from the link budget using an [https://en.wikipedia.org/wiki/Path_loss "empirical formula"] of Okumura-Hata.&nbsp; It holds:&nbsp; $ {r}\ [{\rm km}] = 10^{({\rm LinkBudget}- 137)/35}= 10^{0.0857}\approx 1.22 . $
+#The&nbsp; '''maximum cell radius'''&nbsp; can be determined from the link budget using an [https://en.wikipedia.org/wiki/Path_loss &raquo;empirical formula&laquo;] of Okumura-Hata.&nbsp; It holds:&nbsp; $ {r}\ [{\rm km}] = 10^{({\rm LinkBudget}- 137)/35}= 10^{0.0857}\approx 1.22 . $
 <br><br><br><br><br>

@@ Line 225: / Line 225: @@
-*In UMTS,&nbsp; the receive '''KORREKTUR: receiver''' filter&nbsp; $H_{\rm E}f) = H_{\rm S}(f)$&nbsp; is matched to the transmitter&nbsp; $($"matched filter"$)$&nbsp; and the overall frequency response&nbsp; $H(f) = H_{\rm S}(f) \cdot H_{\rm E}(f)$&nbsp; satisfies the&nbsp; [[Digital_Signal_Transmission/Properties_of_Nyquist_Systems#First_Nyquist_criterion_in_the_frequency_domain|"first Nyquist criterion"]]:
+*In UMTS,&nbsp; the receiver filter&nbsp; $H_{\rm E}f) = H_{\rm S}(f)$&nbsp; is matched to the transmitter&nbsp; $($"matched filter"$)$&nbsp; and the overall frequency response&nbsp; $H(f) = H_{\rm S}(f) \cdot H_{\rm E}(f)$&nbsp; satisfies the&nbsp; [[Digital_Signal_Transmission/Properties_of_Nyquist_Systems#First_Nyquist_criterion_in_the_frequency_domain|"first Nyquist criterion"]]:
 :$$ H(f) = H_{\rm CRO}(f)  =   \left\{ \begin{array}{c}    1 \\  0 \\  \cos^2 \left( \frac {\pi \cdot (|f| - f_1)}{2 \cdot (f_2 - f_1)} \right)\end{array} \right.\quad
 \begin{array}{*{1}c} {\rm{for}} \\ {\rm{for}}\\  {\rm else }\hspace{0.05cm}.  \end{array}
@@ Line 306: / Line 306: @@
 Thereby one receives at the correlator output the sum of
 [[File:EN_Bei_T_4_3_S6a_v2.png|right|frame|Single-user receiver with matched filter]]
-*the&nbsp; "autocorrelation '''KORREKTUR: auto-correlation''' function"&nbsp; of the spreading code and
+*the&nbsp; "auto-correlation  function"&nbsp; of the spreading code and
 *the&nbsp; "cross-correlation function"&nbsp; of all other users with their own spreading code.

@@ Line 517: / Line 517: @@
 '''Transmit power control'''<br>The&nbsp; radio resource management&nbsp; attempts to keep the received power and thus the carrier-to-interference ratio&nbsp; $\rm (CIR)$&nbsp; at the receiver constant,&nbsp; or at least to prevent it from falling below a specified limit.
-An example of the need for power control is the&nbsp; [[Examples_of_Communication_Systems/Telecommunications_Aspects_of_UMTS#Near.E2.80.93Far.E2.80.93Effect|"near-far problem"]],&nbsp; which is known to cause a disconnect.
+An example of the need for power control is the&nbsp; [[Examples_of_Communication_Systems/Telecommunications_Aspects_of_UMTS#Near.E2.80.93far_problem|"near-far problem"]],&nbsp; which is known to cause a disconnect.
 The step size of the power control is&nbsp; $1 \ \rm dB$&nbsp; or&nbsp; $2 \ \rm dB$,&nbsp; and the frequency of the control commands is&nbsp; $1500$&nbsp; commands per second.

@@ Line 431: / Line 431: @@
 Furthermore,&nbsp; this  decisive criterion for UMTS also depends on the following variables:
-#The topology and user behavior&nbsp; $($number ofservices called up$)$,
+#The topology and user behavior&nbsp; $($number of services called up$)$,
 #the spreading factor&nbsp; $J$&nbsp; and the orthogonality of the used spreading code.