Aufgaben:Exercise 4.4: Cellular UMTS Architecture - Revision history

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	[[de:Aufgaben:4.~~4_Zellulare_UMTS~~-Architektur]]		[[de:Aufgaben:Aufgabe 4.4: Zellulare UMTS-Architektur]]

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			[[de:Aufgaben:4.4_Zellulare_UMTS-Architektur]]

Guenter at 15:05, 15 February 2023

2023-02-15T15:05:35Z

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	'''(1)'''  Only the <u>last statement</u> is correct:		'''(1)'''  Only the  <u>last statement</u>  is correct:
	*Since the range of radio signals decreases with increasing frequency at the same transmission power, the radio cells at UMTS (carrier frequency around $2 \ \rm GHz$) are significantly smaller than at GSM (in the D-network around $900 \ \rm MHz$).		*Since the range of radio signals decreases with increasing frequency at the same transmission power,  the radio cells at UMTS  $($carrier frequency around  $2 \ \rm GHz)$  are significantly smaller than at GSM  $($in the D-network around  $900 \ \rm MHz)$.
	*The maximum data rates for UMTS (which are more theoretical limits) are as follows for
	:*a macro cell up to $144 \ \rm kbit/s$,		*The maximum data rates for UMTS  $($which are more theoretical limits$)$ are as follows for
	:*a picocell up to $2 \ \rm Mbit/s$.		:*a macro cell up to  $144 \ \rm kbit/s$,
			:*a picocell up to  $2 \ \rm Mbit/s$.


	'''(2)'''  Correct are <u>all statements</u>:
	*The two definitions for intracell and intercell interference are correct.		'''(2)'''  Correct are  <u>all statements</u>:
	*Applying these to the scenario at hand (graph on the information page), we see.		*The two definitions for intracell and intercell interference are correct.

			*Applying these to the scenario at hand  $($graph on the information page$)$,  we see.
	:*<u>Intra</u>cell interference for $f_{1} = f_{2}$,		:*<u>Intra</u>cell interference for $f_{1} = f_{2}$,
	:*<u>Inter</u>cell interference for $f_{3} = f_{4}$.		:*<u>Inter</u>cell interference for $f_{3} = f_{4}$.
	*<u>Intra</u>cell interference is more severe than <u>Inter</u>cell interference because of the usually smaller distance of the interferers from the receiver, that is, it causes a smaller CIR (''carrier-to-interference ratio'').
			*<u>Intra</u>cell interference is more severe than  <u>Inter</u>cell interference because of the usually smaller distance of the interferers from the receiver,  that is,  it causes a smaller CIR  $($"carrier-to-interference ratio"$)$.



	'''(3)'''  Correct <u>statements 1 and 2</u> ~~are~~:		'''(3)'''  Correct are the  <u>statements 1 and 2</u>:
	*~~Cellular respiration~~ is accurately described by the first two statements.		*Cell breathing is accurately described by the first two statements.
	*With fewer participants ~~now~~ transmitting on a frequency, the negative influence of intracell interference is reduced.
			*With fewer participants transmitting on a frequency,  the negative influence of intracell interference is reduced.

	*The participants in neighboring cells transmit on other frequencies and thus interfere much less.		*The participants in neighboring cells transmit on other frequencies and thus interfere much less.
	*An alternative to cell breathing would be to maintain the cell size but reduce the ~~transmit~~ power of all participants within the cell, but this also means a reduction in the reception quality.
			*An alternative to cell breathing would be to maintain the cell size but reduce the transmitted power of all participants within the cell,  <br>but this also means a reduction in the reception quality.

	*The last proposed solution is simply wrong.		*The last proposed solution is simply wrong.


	'''(4)'''  Correct are <u>all statements</u>:
	*For example, downlink data is split in ~~the ''Radio Network Controller'' (RNC)~~, broadcast over the participating "Node Bs", and reassembled in the mobile station.		'''(4)'''  Correct are  <u>all statements</u>:
	*With ~~''soft handover~~,'' a mobile can communicate with up to three base stations simultaneously.		*For example,  the downlink data is split in theRNC,  broadcast over the participating  "Node Bs",  and reassembled in the mobile station.
	*This variant is of course superior to ''Hard Handover'', but also involves greater effort.
			*With  "Soft Handover",  a mobile can communicate with up to three base stations simultaneously.

			*This variant is of course superior to  "Hard Handover",  but also involves greater effort.

	{{ML-Fuß}}		{{ML-Fuß}}

Guenter at 14:50, 15 February 2023

2023-02-15T14:50:10Z

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	There are three different types of radio cells with a hierarchical structure:		There are three different types of radio cells with a hierarchical structure:
	*»'''Macrocells'''«:  $\text{4 km}$  to  $\text{6 km}$  in diameter,  speeds allowed up to  $\text{500 km/h}$.		#»'''Macrocells'''«:  $\text{4 km}$  to  $\text{6 km}$  in diameter,  speeds allowed up to  $\text{500 km/h}$.
			#»'''Microcells'''«:  $\text{1 km}$  to  $\text{2 km}$  indiameter,  maximum speed allowed  $\text{120 km/h}$.
			#»'''Picocells'''«:  Diameter up to  $\text{100 m}$,  many participants,  extremely high data volume.

	*»'''Microcells'''«:  $\text{1 km}$  to  $\text{2 km}$  indiameter,  maximum speed allowed  $\text{120 km/h}$.

	*~~»'''Picocells'''«:~~  ~~Diameter up to~~  $\text{~~100 m~~}$,  ~~many participants,~~  ~~extremely high data volume~~.		A macrocell can potentially overlay a large number of microcells and picocells.
			*For a microcell,  the maximum data rate is  $\text{384 kbit/s}$  for the maximum speed of  $\text{120 km/h}$.

			*Subtask  '''(1)'''  deals with the maximum data rates allowed in a macrocell and a picocell.

	A macrocell can potentially overlay a large number of microcells and picocells. For a microcell, the maximum data rate is $384 \rm kbit/s$ for the maximum speed of $120 \rm km/h$. Subtask (1) deals with the maximum data rates allowed in a macrocell and a picocell.

	In connection with the cellular structure of UMTS, terms are often used which will be explained in this task:		In connection with the cellular structure of UMTS,  terms are often used which will be explained in this task:
	*intracell interference and intercell interference,		#Intracell interference and intercell interference,
	*cell breathing,		#cell breathing,
	*handover.		#handover.



	Hints:		<u>Hints:</u>
	*This exercise belongs to the chapter [[Examples_of_Communication_Systems/UMTS_Network_Architecture\|"UMTS Network Architecture"]].		*This exercise belongs to the chapter  [[Examples_of_Communication_Systems/UMTS_Network_Architecture\|"UMTS Network Architecture"]].
	*Reference is made in particular to the ~~pages~~ [[Examples_of_Communication_Systems/UMTS_Network_Architecture#Access_level_architecture\|"Access level architecture"]] ~~und~~ [[Examples_of_Communication_Systems/UMTS_Network_Architecture#Handover_in_UMTS\|"Handover in UMTS"]].
			*Reference is made in particular to the sections  [[Examples_of_Communication_Systems/UMTS_Network_Architecture#Access_level_architecture\|"Access level architecture"]]  and  [[Examples_of_Communication_Systems/UMTS_Network_Architecture#Handover_in_UMTS\|"Handover in UMTS"]].


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	{Which of the following statements are true?		{Which of the following statements are true?
	\|type="[]"}		\|type="[]"}
	- UMTS (carrier frequency around $2 \ \rm GHz$) has larger radio cells than GSM (carrier frequency around $900 \ \rm MHz$).		- UMTS  $($carrier frequency around  $2 \ \rm GHz)$  has larger radio cells than GSM  $($carrier frequency around  $900 \ \rm MHz)$.
	- The data rate is greater in a macrocell than in a microcell.		- The data rate is greater in a macrocell than in a microcell.
	+ The data rate is greater in a picocell than in a microcell.		+ The data rate is greater in a picocell than in a microcell.

	{Are the following statements regarding ''interference~~'' correct~~?		{Are the following statements correct regarding  "interference"?
	\|type="[]"}		\|type="[]"}
	+ Intracell interference occurs when multiple participants in the same cell use the same frequency channel.		+ Intracell interference occurs when multiple participants in the same cell use the same frequency channel.
	+ Intercell interference occurs when the same frequency is used by subscribers in different cells.		+ Intercell interference occurs when the same frequency is used by subscribers in different cells.
	+ In the scenario shown, intracell interference occurs when the frequencies $f_{1}$ and $f_{2}$ are the same.		+ In the scenario shown,  intracell interference occurs when the frequencies  $f_{1}$  and  $f_{2}$  are the same.
	+ In the scenario shown, intercell interference occurs when frequencies $f_{3}$ and $f_{4}$ are equal.		+ In the scenario shown,  intercell interference occurs when frequencies  $f_{3}$  and  $f_{4}$  are equal.

	{What is meant by ~~''cellular respiration''~~?		{What is meant by  "cell breathing"?
	\|type="[]"}		\|type="[]"}
	+ If the number of active participants in the cell increases   ⇒   greater interference power, the cell radius is reduced.		+ If the number of active participants in the cell increases   ⇒   greater interference power,  the cell radius is reduced.
	+ The supply of subscribers at the edge of a busy cell is taken over by a less busy neighboring cell.		+ The supply of subscribers at the edge of a busy cell is taken over by a less busy neighboring cell.
	- Cell breathing describes a mechanism for best matching the data rate to the current traffic.		- Cell breathing describes a mechanism for best matching the data rate to the current traffic.

	{Which of the following statements about ''handover'' are true?		{Which of the following statements about  "handover"  are true?
	\|type="[]"}		\|type="[]"}
	+ The ~~goal~~ is ~~to make~~ the transition of a mobile subscriber from one cell to another appear ~~to be~~ uninterrupted.		+ The aim is for the transition of a mobile subscriber from one cell to another to appear uninterrupted.
	+ ''Hard Handover'' is when the connection is abruptly switched to another connection.		+ "Hard Handover"  is when the connection is abruptly switched to another connection.
	+ ~~In ''~~Soft Handover'', the handover of a subscriber from one base station to another is gradual.		+ With  "Soft Handover",  the handover of a subscriber from one base station to another is gradual.

	</quiz>		</quiz>

Guenter at 14:04, 15 February 2023

2023-02-15T14:04:09Z

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	[[File:P_ID1934__Bei_A_4_4.png\|right\|frame\|UMTS cellular architecture]]		[[File:P_ID1934__Bei_A_4_4.png\|right\|frame\|UMTS cellular architecture]]
	In order to enable a ~~nationwide~~ network with low transmission power and sufficient frequency economy, radio cells are set up for UMTS - as for [[Examples_of_Communication_Systems/General_Description_of_GSM\|"GSM"]].		In order to enable a nation-wide network with low transmission power and sufficient frequency economy,  radio cells are set up for UMTS  as for&Nbbsp; [[Examples_of_Communication_Systems/General_Description_of_GSM\|"GSM"]].

	For simple system studies, hexagonal cells are assumed as shown in the diagram. In reality, the radio cells vary in size and are also adapted to the existing topology and infrastructure of the coverage area.		For simple system studies,  hexagonal cells are assumed as shown in the diagram.  In reality,  the radio cells vary in size and are also adapted to the existing topology and infrastructure of the coverage area.

	There are three different types of radio cells with a hierarchical structure:		There are three different types of radio cells with a hierarchical structure:
	*${~~\rm Macrocells~~}$:   4 to 6 km in diameter, speeds up to 500 km/h ~~allowed~~.		*»'''Macrocells'''«:  $\text{4 km}$  to  $\text{6 km}$  in diameter,  speeds allowed up to  $\text{500 km/h}$.
	*${~~\rm Microcells~~}$:   1 to 2 km ~~in diameter~~, maximum speed allowed 120 km/h.
	*~~${\rm Picocell}$~~:   ~~diameter~~ up to 100 m, many participants, extremely high data volume.		*»'''Microcells'''«:  $\text{1 km}$  to  $\text{2 km}$  indiameter,  maximum speed allowed  $\text{120 km/h}$.

			*»'''Picocells'''«:  Diameter up to  $\text{100 m}$,  many participants,  extremely high data volume.

Noah at 01:40, 13 February 2023

2023-02-13T01:40:08Z

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	[[File:P_ID1934__Bei_A_4_4.png\|right\|frame\|UMTS cellular architecture]]		[[File:P_ID1934__Bei_A_4_4.png\|right\|frame\|UMTS cellular architecture]]
	~~Um ein flächendeckendes Netz mit geringer Sendeleistung und ausreichender Frequenzökonomie zu ermöglichen~~, ~~werden bei~~ UMTS ~~– wie auch bei~~ [[Examples_of_Communication_Systems/General_Description_of_GSM\|"GSM"]] ~~– Funkzellen eingerichtet~~.		In order to enable a nationwide network with low transmission power and sufficient frequency economy, radio cells are set up for UMTS - as for [[Examples_of_Communication_Systems/General_Description_of_GSM\|"GSM"]].

	~~Für einfache Systemuntersuchungen geht man dabei von hexagonalen Zellen wie~~ in ~~der Grafik angedeutet aus~~. In ~~Realität sind die Funkzellen unterschiedlich groß und zudem an die vorliegende Topologie und die Infrastruktur des Versorgungsgebietes angepasst~~.		For simple system studies, hexagonal cells are assumed as shown in the diagram. In reality, the radio cells vary in size and are also adapted to the existing topology and infrastructure of the coverage area.

	~~Es gibt drei unterschiedliche Typen von Funkzellen mit einem hierarchischen Aufbau~~:		There are three different types of radio cells with a hierarchical structure:
	*${\rm ~~Makrozellen~~}$:   4 ~~bis~~ 6 km ~~Durchmesser~~, ~~Geschwindigkeiten bis zu~~ 500 km/h ~~erlaubt~~.		*${\rm Macrocells}$:   4 to 6 km in diameter, speeds up to 500 km/h allowed.
	*${\rm ~~Mikrozellen~~}$:   1 ~~bis~~ 2 km ~~Durchmesser~~, ~~maximal zulässige Geschwindigkeit~~ 120 km/h.		*${\rm Microcells}$:   1 to 2 km in diameter, maximum speed allowed 120 km/h.
	*${\rm ~~Pikozelle~~}$:   ~~Durchmesser bis~~ 100 m, ~~viele Teilnehmer~~, ~~extrem hohes Datenaufkommen~~.		*${\rm Picocell}$:   diameter up to 100 m, many participants, extremely high data volume.


	~~Eine Makrozelle kann möglicherweise eine Vielzahl von Mikro– und Pikozellen überlagern~~. ~~Für eine Mikrozelle beträgt die maximale Datenrate~~ $384 \ \rm kbit/s$ ~~für die maximale Geschwindigkeit von~~ $120 \ \rm km/h$. ~~Mit den maximal zulässigen Datenraten in einer Makrozelle und einer Pikozelle beschäftigt sich die Teilaufgabe~~ (1).		A macrocell can potentially overlay a large number of microcells and picocells. For a microcell, the maximum data rate is $384 \rm kbit/s$ for the maximum speed of $120 \rm km/h$. Subtask (1) deals with the maximum data rates allowed in a macrocell and a picocell.

	~~Im Zusammenhang mit der zellularen Struktur von UMTS werden häufig Begriffe verwendet, die~~ in ~~dieser Aufgabe erklärt werden sollen:~~
	*Intrazellinterferenz und Interzellinterferenz,
	*Zellatmung,
	*Handover.

			In connection with the cellular structure of UMTS, terms are often used which will be explained in this task:
			*intracell interference and intercell interference,
			*cell breathing,
			*handover.

Noah at 01:38, 13 February 2023

2023-02-13T01:38:47Z

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Guenter at 14:56, 24 January 2023

2023-01-24T14:56:43Z

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	[[Category:Examples of Communication Systems: Exercises\|^4.2 ~~UMTS–Netzarchitektur~~		[[Category:Examples of Communication Systems: Exercises\|^4.2 UMTS Network Architecture

	^]]		^]]

Guenter: Guenter moved page Aufgaben:Aufgabe 4.4: Zellulare UMTS-Architektur to Aufgaben:Exercise 4.4: Cellular UMTS Architecture

2023-01-24T14:55:02Z

Guenter moved page Aufgaben:Aufgabe 4.4: Zellulare UMTS-Architektur to Aufgaben:Exercise 4.4: Cellular UMTS Architecture

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	'''(4)'''  Richtig sind <u>alle Aussagen</u>:		'''(4)'''  Richtig sind <u>alle Aussagen</u>:
	*Beispielsweise werden die Downlink–Daten im ''Radio Network Controller'' (RNC) aufgeteilt, über die beteiligten "Node Bs~~”~~ ausgestrahlt und in der Mobilstation wieder zusammengesetzt.		*Beispielsweise werden die Downlink–Daten im ''Radio Network Controller'' (RNC) aufgeteilt, über die beteiligten "Node Bs" ausgestrahlt und in der Mobilstation wieder zusammengesetzt.
	*Bei ''Soft Handover'' kann ein Mobiltelefon mit bis zu drei Basisstationen gleichzeitig kommunizieren.		*Bei ''Soft Handover'' kann ein Mobiltelefon mit bis zu drei Basisstationen gleichzeitig kommunizieren.
	*Diese Variante ist natürlich dem ''Hard Handover'' überlegen, aber auch mit einem größeren Aufwand verbunden.		*Diese Variante ist natürlich dem ''Hard Handover'' überlegen, aber auch mit einem größeren Aufwand verbunden.