Difference between revisions of "Aufgaben:Exercise 4.8: HSDPA and HSUPA"
m (Text replacement - "Category:Aufgaben zu Beispiele von Nachrichtensystemen" to "Category:Examples of Communication Systems: Exercises") |
|||
(6 intermediate revisions by 2 users not shown) | |||
Line 3: | Line 3: | ||
}} | }} | ||
− | [[File:P_ID1983__Bei_A_4_8.png|right|frame| | + | [[File:P_ID1983__Bei_A_4_8.png|right|frame|Overview of HSDPA and HSUPA]] |
− | + | To achieve better quality of service, the UMTS Release 99 standard was further developed. | |
− | |||
− | |||
+ | The most important further developments were: | ||
+ | *UMTS Release 5 with $\rm HSDPA$ $($2002$)$, | ||
− | + | *UMTS Release 6 with $\rm HUDPA$ $($2004$)$. | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
+ | Collectively, these developments are known as »'''High-Speed Packet Access'''« $\rm (HSPA)$. | ||
− | + | The chart shows some of the features of HSDPA and HSUPA that particularly contribute to the increase in performance: | |
− | + | #Both use »'''Hybrid Automatic Repeat Request'''« $\rm (HARQ)$ and »'''Node B Scheduling'''«. | |
− | + | #With HSDPA, the high-speed transport channel »'''HS-PDSCH'''« $($"High-Speed Physical Downlink Shared Channel"$)$ was newly introduced, which is shared by multiple users and allows simultaneous transmission of the same data to many subscribers. | |
− | + | #In the HSUPA standard, there is the additional transport channel »'''Enhanced Dedicated Channel'''« $($'''E-DCH'''$)$. Among other things, this minimizes the negative impact of applications with very intensive or highly varying data volumes. | |
+ | #In HSPA, adaptive modulation and coding is used; the transmission rate is adjusted accordingly. | ||
+ | #In good conditions, a $\text{16-QAM}$ $(4$ bit per symbol$)$ or $\text{64-QAM}$ $(6$ bit per symbol$)$ is used, in worse conditions only $\text{4-QAM (QPSK)}$. | ||
+ | #The maximum achievable bit rate depends on receiver performance, but also on "transport format and resource combinations" $\text{(TFRC)}$. | ||
− | + | Of the ten specified TFRC classes, only a few are listed here arbitrarily: | |
+ | *$\text{TFRC2:}$ $\text{4-QAM (QPSK)}$ with code rate $R_{\rm C} =1/2$ ⇒ bit rate: $240 \hspace{0.15cm} \rm kbit/s$, | ||
+ | *$\text{TFRC4:}$ $\text{16-QAM}$ with code rate $R_{\rm C} =1/2$ ⇒ bit rate: $480 \hspace{0.15cm} \rm kbit/s$, | ||
+ | *$\text{TFRC8:}$ $\text{64-QAM}$ with code rate $R_{\rm C} =3/4$ ⇒ bit rate: $1080 \hspace{0.15cm} \rm kbit/s$. | ||
+ | Other TFRC classes are discussed in the subtasks '''(4)''' and '''(5)''' . | ||
− | + | <u>Hints:</u>: This exercise belongs to the chapter [[Examples_of_Communication_Systems/Further_Developments_of_UMTS|"Further Developments of UMTS"]]. | |
− | |||
− | === | + | ===Questions=== |
<quiz display=simple> | <quiz display=simple> | ||
− | { | + | {Which standard allows the highest data rates? |
|type="[]"} | |type="[]"} | ||
− | - UMTS | + | - UMTS $($Release 99$)$, |
+ HSDPA, | + HSDPA, | ||
- HSUPA. | - HSUPA. | ||
− | { | + | {What is meant by "$\rm HARQ$" and what does it achieve? |
|type="[]"} | |type="[]"} | ||
− | + | + | + Transmission of a frame starts only after evaluation of the sent control data by the receiver. |
− | + | + | + If the transmission is error-free, a positive "acknowledgement" is sent, otherwise a NACK $($"Non acknowledgement"$)$. |
− | - | + | - The achievable data rate is lowered by HARQ, assuming the AWGN channel and equal $E_{\rm B}/N_{0}$. |
− | { | + | {What is meant by "$\rm Node \ B \ Scheduling$" ? What can be achieved with it? |
|type="[]"} | |type="[]"} | ||
− | + | + | + Assigning priorities to the individual data frames. |
− | + | + | + The user with the highest priority gets the best channel. |
− | + | + | + Scheduling significantly increases the cell capacity. |
− | { | + | {What is the bit rate of $\rm TFRC3$ $($QPSK, code rate $R_{\rm C} =3/4)$ ? |
|type="{}"} | |type="{}"} | ||
$R_{\rm B} \ = \ $ { 360 3% } $\ \rm kbit/s$ | $R_{\rm B} \ = \ $ { 360 3% } $\ \rm kbit/s$ | ||
− | { | + | {What is the bit rate of $\rm TFRC10$ $($64-QAM, code rate $R_{\rm C} =1)$ ? |
|type="{}"} | |type="{}"} | ||
$R_{\rm B} \ = \ $ { 1440 3% } $\ \rm kbit/s$ | $R_{\rm B} \ = \ $ { 1440 3% } $\ \rm kbit/s$ | ||
</quiz> | </quiz> | ||
− | === | + | ===Solution=== |
{{ML-Kopf}} | {{ML-Kopf}} | ||
− | '''(1)''' | + | '''(1)''' Correct is <u>solution 2</u>: |
− | * | + | *For conventional UMTS, the data transfer rate is between $144 \ \rm kbit/s$ and $2 \ \rm Mbit/s$. |
− | |||
− | |||
+ | *For HSDPA $($the abbreviation stands for "High-Speed Downlink Packet Access"$)$, data rates between $500 \ \rm kbit/s$ and $3.6 \ \rm Mbit/s$ are specified, and as a limit even $14.4 \ \rm Mbit/s$. | ||
+ | *HSUPA $($"High-Speed Uplink Packet Access"$)$ refers to the uplink channel, which always has a lower data rate than the downlink. In practice, data rates up to $800 \ \rm kbit/s$ are achieved, the theoretical limit being $5.8 \ \rm Mbit/s$. | ||
− | '''(2)''' | + | |
− | * | + | |
− | * | + | '''(2)''' The <u>first two statements</u> are correct: |
− | * | + | *For a detailed description of the HARQ procedure, see the [[Examples_of_Communication_Systems/Further_Developments_of_UMTS#HARQ_procedure_and_.22Node_B_Scheduling.22|"theory section"]]. |
+ | |||
+ | *In contrast, statement 3 is not correct. The [[Examples_of_Communication_Systems/Further_Developments_of_UMTS#HARQ_procedure_and_.22Node_B_Scheduling.22 |"diagram"]] in the theory part rather shows that for $10 \cdot {\rm lg}\ E_{\rm B}/N_{0} = 0 \ \rm dB$ $($AWGN channel$)$ the data rate can be increased from $600 \ \rm kbit/s$ to nearly $800 \ \rm kbit/s$. | ||
+ | |||
+ | *Below $-2 \ \rm dB$, a usable transmission is only possible with HARQ. In contrast, for good channels $(E_{\rm B}/N_{0} > 2 \ \rm dB)$, HARQ is not required. | ||
− | '''(3)''' <u> | + | '''(3)''' <u>All statements are correct</u>. For further guidance on "Node B Scheduling", see [[Examples_of_Communication_Systems/Further_Developments_of_UMTS#HARQ_procedure_and_.22Node_B_Scheduling.22|"theory section"]]. |
− | '''(4)''' | + | '''(4)''' The bit rate $R_{\rm B}\hspace{0.15cm} \underline{= 360 \ \rm kbit/s}$ is larger than the bit rate of TFRC2 by a factor $(3/4)/(1/2) = 1.5$ because of the larger code rate. |
− | '''(5)''' | + | '''(5)''' With the code rate $R_{\rm C} =1$, QPSK $(2 \ \rm bit \ per \ symbol)$ would result in the bit rate $480 \ \rm kbit/s$. |
− | |||
− | * | + | *For $\text{64-QAM}$ $(6 \ \rm bit \ per \ symbol)$ the value is three times: $R_{\rm B} \hspace{0.15cm}\underline{= 1440 \ \rm kbit/s}$. |
{{ML-Fuß}} | {{ML-Fuß}} | ||
Line 102: | Line 105: | ||
− | [[Category:Examples of Communication Systems: Exercises|^4.4 | + | [[Category:Examples of Communication Systems: Exercises|^4.4 Further Developments of |
^]] | ^]] |
Latest revision as of 17:22, 4 March 2023
To achieve better quality of service, the UMTS Release 99 standard was further developed.
The most important further developments were:
- UMTS Release 5 with $\rm HSDPA$ $($2002$)$,
- UMTS Release 6 with $\rm HUDPA$ $($2004$)$.
Collectively, these developments are known as »High-Speed Packet Access« $\rm (HSPA)$.
The chart shows some of the features of HSDPA and HSUPA that particularly contribute to the increase in performance:
- Both use »Hybrid Automatic Repeat Request« $\rm (HARQ)$ and »Node B Scheduling«.
- With HSDPA, the high-speed transport channel »HS-PDSCH« $($"High-Speed Physical Downlink Shared Channel"$)$ was newly introduced, which is shared by multiple users and allows simultaneous transmission of the same data to many subscribers.
- In the HSUPA standard, there is the additional transport channel »Enhanced Dedicated Channel« $($E-DCH$)$. Among other things, this minimizes the negative impact of applications with very intensive or highly varying data volumes.
- In HSPA, adaptive modulation and coding is used; the transmission rate is adjusted accordingly.
- In good conditions, a $\text{16-QAM}$ $(4$ bit per symbol$)$ or $\text{64-QAM}$ $(6$ bit per symbol$)$ is used, in worse conditions only $\text{4-QAM (QPSK)}$.
- The maximum achievable bit rate depends on receiver performance, but also on "transport format and resource combinations" $\text{(TFRC)}$.
Of the ten specified TFRC classes, only a few are listed here arbitrarily:
- $\text{TFRC2:}$ $\text{4-QAM (QPSK)}$ with code rate $R_{\rm C} =1/2$ ⇒ bit rate: $240 \hspace{0.15cm} \rm kbit/s$,
- $\text{TFRC4:}$ $\text{16-QAM}$ with code rate $R_{\rm C} =1/2$ ⇒ bit rate: $480 \hspace{0.15cm} \rm kbit/s$,
- $\text{TFRC8:}$ $\text{64-QAM}$ with code rate $R_{\rm C} =3/4$ ⇒ bit rate: $1080 \hspace{0.15cm} \rm kbit/s$.
Other TFRC classes are discussed in the subtasks (4) and (5) .
Hints:: This exercise belongs to the chapter "Further Developments of UMTS".
Questions
Solution
(1) Correct is solution 2:
- For conventional UMTS, the data transfer rate is between $144 \ \rm kbit/s$ and $2 \ \rm Mbit/s$.
- For HSDPA $($the abbreviation stands for "High-Speed Downlink Packet Access"$)$, data rates between $500 \ \rm kbit/s$ and $3.6 \ \rm Mbit/s$ are specified, and as a limit even $14.4 \ \rm Mbit/s$.
- HSUPA $($"High-Speed Uplink Packet Access"$)$ refers to the uplink channel, which always has a lower data rate than the downlink. In practice, data rates up to $800 \ \rm kbit/s$ are achieved, the theoretical limit being $5.8 \ \rm Mbit/s$.
(2) The first two statements are correct:
- For a detailed description of the HARQ procedure, see the "theory section".
- In contrast, statement 3 is not correct. The "diagram" in the theory part rather shows that for $10 \cdot {\rm lg}\ E_{\rm B}/N_{0} = 0 \ \rm dB$ $($AWGN channel$)$ the data rate can be increased from $600 \ \rm kbit/s$ to nearly $800 \ \rm kbit/s$.
- Below $-2 \ \rm dB$, a usable transmission is only possible with HARQ. In contrast, for good channels $(E_{\rm B}/N_{0} > 2 \ \rm dB)$, HARQ is not required.
(3) All statements are correct. For further guidance on "Node B Scheduling", see "theory section".
(4) The bit rate $R_{\rm B}\hspace{0.15cm} \underline{= 360 \ \rm kbit/s}$ is larger than the bit rate of TFRC2 by a factor $(3/4)/(1/2) = 1.5$ because of the larger code rate.
(5) With the code rate $R_{\rm C} =1$, QPSK $(2 \ \rm bit \ per \ symbol)$ would result in the bit rate $480 \ \rm kbit/s$.
- For $\text{64-QAM}$ $(6 \ \rm bit \ per \ symbol)$ the value is three times: $R_{\rm B} \hspace{0.15cm}\underline{= 1440 \ \rm kbit/s}$.