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Mobile Communications/Non-Frequency-Selective Fading With Direct Component
...ncy_selective_fading| $\text{Rayleigh distribution}$]]  describes the mobile communication channel under the assumption that there is no direct path and ...lang, T.:  Mobile Communications.   Lecture notes. Institute for Communications Engineering.   Technical University of Munich, 2008.</ref>:

7 KB (1,061 words) - 16:55, 3 February 2023
Exercise 3.4: Different Voice Codecs
...2 \ \rm kbit/s$  and stands for the common quality standard in mobile communications nowadays. ...standardized the Adaptive Multi Rate Codec"  $\rm (AMR)$  for GSM.  This provides eight different modes with data rates between&nbsp

6 KB (975 words) - 13:28, 23 January 2023
Exercise 3.9: Further Developments of UMTS
*$\rm EDGE$:   "Enhanced Data Rates for GSM Evolution", ...ions standards, whereby we specify so-called  "peak data rates"  for HSCSD, GPRS and EDGE, which were difficult to achieve under real conditions

6 KB (888 words) - 14:37, 23 March 2021
Exercise 2.1: General Description of xDSL
...dization of ${\boldsymbol{\rm xDSL}}$ began, with the "x" as a placeholder for one letter each. A distinction is made between the following system variant The questions for this exercise are limited to basic things such as the question:  "Is t

7 KB (997 words) - 15:53, 5 March 2023
Exercise 2.2: Simple Two-Path Channel Model
[[File:EN_Mob_A_2_2.png|right|frame|Two equivalent models for the two-path channel]] Here we consider a two-path channel for mobile radio according to the adjacent graph, characterized by the model parameter

7 KB (1,101 words) - 14:37, 23 March 2021
Mobile Communications/General Description of Time Variant Systems
|Nächste Seite=Multipath Reception in Mobile Communications}} ...les,  a channel property which is also of great importance for mobile communications.  As in the entire book,  the description is given in the equival

10 KB (1,542 words) - 15:41, 29 January 2023
Exercise 4.3Z: Multiple-Access Methods in LTE
In the case of the 4G mobile radio system LTE, there was a change not only in the type of modulation com *Code Division Multiple Access  $\rm (CDMA)$  is used in the 3G mobile system  [[Examples_of_Communication_Systems/Allgemeine_Beschreibung_vo

4 KB (654 words) - 13:47, 22 September 2021
Exercise 2.4: 2D Transfer Function
...-dimensional impulse response  $h(\tau, \hspace{0.05cm}t)$  of a mobile radio system in magnitude representation. For all other values of  $\tau$,  we have  $h(\tau, \hspace{0.05

6 KB (918 words) - 14:38, 23 March 2021
Modulation Methods/Tasks and Classification
...ision Multiple Access"$)$,  a specific spreading sequence is provided for each subscriber.  Such spreading sequences – and thus also the overa ...Mobile_Communications_Standard|$\rm LTE$]]  of the book  "Mobile Communications".

13 KB (1,929 words) - 17:11, 19 January 2023
Exercise 1.4: Rayleigh PDF and Jakes PDS
[[File:P_ID2119__Mob_A_1_4.png|right|frame| PDF and  $|z(t)|$  for Rayleigh fading with Doppler effect]] We consider two different mobile radio channels with  [[Mobile_Communications/Wahrscheinlichkeitsdichte

7 KB (1,106 words) - 08:05, 18 September 2022
Exercise 1.1: Dual Slope Loss Model
...)$. The variable name "$V$" stands for "Verlust", which is the German word for "loss": * For  $d \le d_{\rm BP}$  and the exponent   $\gamma_0$  we

8 KB (1,341 words) - 14:37, 23 March 2021
Mobile Communications/Multi-Path Reception in Mobile Communications
...ansfer function and the impulse response are time–independent.  For all times  $t$  applies  $H(f, \hspace{0.05cm}t) = H(f)$&nbs ...proportionally with the path length  $d_1$ .   For example, for the distance  $d_1 = 3 \ \rm km$  and the speed of light  $c

14 KB (2,197 words) - 15:44, 29 January 2023
Exercise 4.2: FDD, TDD and Half-Duplex
Duplex processes are required in mobile radio to ensure that the uplink  $\rm (UL)$  and downlink  $ ...shown in the graph on the data page, only one frequency band is sufficient for TTD.

4 KB (678 words) - 14:37, 23 March 2021
Exercise 4.4: Modulation in LTE
[[File:EN_Mob_A_4_4_neu1.png|right|frame|Throughput comparison for LTE]] ...ed as  $b^{2}–{\rm QAM}$.  The signal space constellations for 16-QAM and 64-QAM are shown on the right.  The bright dots indicate th

5 KB (712 words) - 14:37, 23 March 2021
Exercise 1.3: Rayleigh Fading
An example of such a Rayleigh channel occurs in urban mobile communications when narrow-band signals are used with ranges between  $50$  and& ...$y(t)$  there may be statistical dependence, but this is not relevant for the solution of the present task.  We assume that  $x(t)$  a

7 KB (1,034 words) - 16:41, 28 May 2021
Exercise 3.7Z: Spread Spectrum in UMTS
For UMTS/CDMA, the so-called  "PN modulation"  is applied: *For the calculation of the chip duration   $T_{\rm C}$,  please refer

4 KB (677 words) - 01:42, 13 November 2022
Exercise 4.08Z: Basics about Interleaving
Interleaving is required,  for example,  for a channel with burst error characteristics in order to distribute the error For turbo codes based on so-called  '''RSC encoder'''  $($"Recursive

6 KB (876 words) - 14:53, 14 December 2022
Exercise 2.2Z: Real Two-Path Channel
...h_Reception_in_Mobile_Communications| Multi–Path Reception in Mobile Communications]]. ...oximation $\sqrt{(1 + \varepsilon)} \approx 1 + \varepsilon/2$  valid for small  $\varepsilon$ ?

6 KB (959 words) - 14:37, 23 March 2021
Examples of Communication Systems/Further Developments of UMTS
|Untermenü=UMTS – Universal Mobile Telecommunications System In order to meet the increasing demand for higher data rates in mobile communications and to ensure ever better quality of service, the UMTS Release 99 standard

15 KB (2,250 words) - 19:21, 25 March 2023
Exercise 2.1Z: 2D-Frequency and 2D-Time Representations
...he graph,  $H(f, \ t)$  is displayed as a function of frequency, for different values of absolute time  $t$  in the range of  $0 {Estimate for which channel the data was recorded.

5 KB (743 words) - 14:37, 23 March 2021