HSDPA channels Code configuration ??

[fahmi]

Hi all,

In hsdpa system we have 2 DL physical channels HS-SCCH and HS-PDSCH. The codes used by HS-PDSCH are those of SF 16 (16 code) in tne code tree and SF 128 for HS-SCCH.

Is it true that :

In a carrier we have in total, 16 HS-PDSCH and 128 HS-SCCH in the the same time ?
For each HS-PDSCH we have an HS-SCCH associated to it ?
In HSDPA we configure only 4 HS-SCCH ?
In a carrier the MAX UE nubmer in the same time is 15 (the number of HS-PDSCH channel)

Waiting for your help plzzzz

BR,
Fahmi.

[auto_art]

Hi all,

In hsdpa system we have 2 DL physical channels HS-SCCH and HS-PDSCH. The codes used by HS-PDSCH are those of SF 16 (16 code) in tne code tree and SF 128 for HS-SCCH.

Is it true that :
In a carrier we have in total, 16 HS-PDSCH and 128 HS-SCCH in the the same time ?
For each HS-PDSCH we have an HS-SCCH associated to it ?
In HSDPA we configure only 4 HS-SCCH ?
In a carrier the MAX UE nubmer in the same time is 15 (the number of HS-PDSCH channel)
Waiting for your help plzzzz

BR,
Fahmi.

first of all maximum 15 codes an be allocated per cell. one code is reserved of signalling of control channels..


In a carrier we have in total, 16 HS-PDSCH and 128 HS-SCCH in the the same time ?
we have only 15 not 16, remember maxhspdchcodes parameter can be set to 15 at max.



For each HS-PDSCH we have an HS-SCCH associated to it ?
yeaah every pdsch has scch to carry signalling for users sharing PDSCH.



In HSDPA we configure only 4 HS-SCCH ?
yeas there are two config available 2 & 4 SCCH.



In a carrier the MAX UE nubmer in the same time is 15 (the number of HS-PDSCH channel?
i wrote this above.


should there be any prob pl write.!

[fantominox]

Hi Fahmi,
1.We can theoretically have up to 15 HS-PDSCHs in carrier, not 16 because we need branches in code tree for common channels. In practice we can achieve 14 HS-PDSCH codes.
In accordance to 3GPP we can use only up to 4 HS-SCCHs in carrier – usually are used codes with lowest available code index in the tree (but only 4 codes are taken from all 128 available in the tree)

2.HS-SCCHs are not associated to each code HS-PDSCH - we can say they concern 15 HS-PDSCH codes in next TTI.

3.In a carrier we can configure up to 4 HS-SCCHs (not more) but 1 or 2 or 3 as well.
Only 4 HS-SCCHs because Ue can listen up to 4 HS-SCCHs simultaneously (4 fingers of rake in Ue).
One HS-SCCHs carries information for 1 user but it is common channel so it doesn’t “belong” to 1 given user (then it would be dedicated channel)
All HS-SCCHs are transmitted simultaneously 2 slots before HS-PDSCH – Ue listening HS-SCCHs get know if in next TTI are HS-PDSCHs destined for it.


4.In a carrier in the same time (in the same TTI) data can be transmitted to up to 4 HSDPA users (because we configure up to 4 HS-SCCHs) , but generally in carrier can be more HSDPA users ( set in admission parameters), data for other users can be transmitted i.e in next TTI.

I think it’s clear explanation

Best Regards
Fantominox

Don’t forget (R) and thx

[fahmi]

Hi Fahmi,
1.We can theoretically have up to 15 HS-PDSCHs in carrier, not 16 because we need branches in code tree for common channels. In practice we can achieve 14 HS-PDSCH codes.
In accordance to 3GPP we can use only up to 4 HS-SCCHs in carrier – usually are used codes with lowest available code index in the tree (but only 4 codes are taken from all 128 available in the tree)

2.HS-SCCHs are not associated to each code HS-PDSCH - we can say they concern 15 HS-PDSCH codes in next TTI.

3.In a carrier we can configure up to 4 HS-SCCHs (not more) but 1 or 2 or 3 as well.
Only 4 HS-SCCHs because Ue can listen up to 4 HS-SCCHs simultaneously (4 fingers of rake in Ue).
One HS-SCCHs carries information for 1 user but it is common channel so it doesn’t “belong” to 1 given user (then it would be dedicated channel)
All HS-SCCHs are transmitted simultaneously 2 slots before HS-PDSCH – Ue listening HS-SCCHs get know if in next TTI are HS-PDSCHs destined for it.


4.In a carrier in the same time (in the same TTI) data can be transmitted to up to 4 HSDPA users (because we configure up to 4 HS-SCCHs) , but generally in carrier can be more HSDPA users ( set in admission parameters), data for other users can be transmitted i.e in next TTI.

I think it’s clear explanation

Best Regards
Fantominox

Don’t forget (R) and thx

Many thanks fantominox (http://www.finetopix.com/member.php?63039-fantominox), it was a very nice explanation, keep helping :) :) :)

[fahmi]

Ok, other question : when using 15 code (SF16) for HSDPA, the codes below HS PDSCH will blocked, and the 16th code will not be used by HS PDSCH so that the lower code in the tree (SF 32 64 128 ..) will not be blocked and will be used by common channels.

So which code will be used by DCH in R99 simultaniously to HSDPA ??

BR,
Fahmi.

[aygo]

25948

HSPA on DL code availability

[Kevin Chen]

Hi Fahmi,
1.We can theoretically have up to 15 HS-PDSCHs in carrier, not 16 because we need branches in code tree for common channels. In practice we can achieve 14 HS-PDSCH codes.
In accordance to 3GPP we can use only up to 4 HS-SCCHs in carrier – usually are used codes with lowest available code index in the tree (but only 4 codes are taken from all 128 available in the tree)

2.HS-SCCHs are not associated to each code HS-PDSCH - we can say they concern 15 HS-PDSCH codes in next TTI.

3.In a carrier we can configure up to 4 HS-SCCHs (not more) but 1 or 2 or 3 as well.
Only 4 HS-SCCHs because Ue can listen up to 4 HS-SCCHs simultaneously (4 fingers of rake in Ue).
One HS-SCCHs carries information for 1 user but it is common channel so it doesn’t “belong” to 1 given user (then it would be dedicated channel)
All HS-SCCHs are transmitted simultaneously 2 slots before HS-PDSCH – Ue listening HS-SCCHs get know if in next TTI are HS-PDSCHs destined for it.


4.In a carrier in the same time (in the same TTI) data can be transmitted to up to 4 HSDPA users (because we configure up to 4 HS-SCCHs) , but generally in carrier can be more HSDPA users ( set in admission parameters), data for other users can be transmitted i.e in next TTI.

I think it’s clear explanation

Best Regards
Fantominox

Don’t forget (R) and thx




Very very clear explanation!

[fantominox]

Hi Kevin,
if you like it - pls add R, thank you.
BR
Fantominox

[nauniux]

Hi Fahmi,
1.We can theoretically have up to 15 HS-PDSCHs in carrier, not 16 because we need branches in code tree for common channels. In practice we can achieve 14 HS-PDSCH codes.
In accordance to 3GPP we can use only up to 4 HS-SCCHs in carrier – usually are used codes with lowest available code index in the tree (but only 4 codes are taken from all 128 available in the tree)

2.HS-SCCHs are not associated to each code HS-PDSCH - we can say they concern 15 HS-PDSCH codes in next TTI.

3.In a carrier we can configure up to 4 HS-SCCHs (not more) but 1 or 2 or 3 as well.
Only 4 HS-SCCHs because Ue can listen up to 4 HS-SCCHs simultaneously (4 fingers of rake in Ue).
One HS-SCCHs carries information for 1 user but it is common channel so it doesn’t “belong” to 1 given user (then it would be dedicated channel)
All HS-SCCHs are transmitted simultaneously 2 slots before HS-PDSCH – Ue listening HS-SCCHs get know if in next TTI are HS-PDSCHs destined for it.


4.In a carrier in the same time (in the same TTI) data can be transmitted to up to 4 HSDPA users (because we configure up to 4 HS-SCCHs) , but generally in carrier can be more HSDPA users ( set in admission parameters), data for other users can be transmitted i.e in next TTI.

I think it’s clear explanation

Best Regards
Fantominox

Don’t forget (R) and thx

Good questions and great answers.

In number 4. can be understood also the license of simultaneous/concurrent users in the cell. In E******* there are licenses for 32 and 64 users configured per cell.

[firstmaxim]

The same HS-SCCH can point to multiple HS-PDSCHs. You don't need individual HS-SCCH for each HS-PDSCH.

Also, if you configure only one HS-SCCH, then it would not be possi ble to apply code multiplexing ie, assign multiple UEs for a given 2ms TTI. This could impact jitter sensitive applications.

[firstmaxim]

You cannot have 16 codes, because there is atleast one code required for HS-SCCH with SF 128. This would block the code allocation on the upstream direction of the OVSF tree, thereby blocking one SF16 code.