LTE Handover Management SAP

Hi All,

This is the preliminary code of Handover Management SAP for GSoC 2013, which mediates the two-way interaction between LteEnbRrc and HandoverAlgorithm.

This patchset also includes 2 implementation of HandoverAlgorithm: Bare and A2Rsrq. The former is an "empty" algorithm to be used if no automatic handover is desired (e.g. in some test scripts), while the latter is the original algorithm from LENA M5.

Note that NRT function is still hardcoded at the moment. My proposed approach to solve this is to make a new class LteAnr (Automatic Neighbour Relation), which will interact with LteEnbRrc via a new SAP interface. The interface methods may include:
1. ANR provides RRC with UE measurements configuration
2. RRC provides ANR with measurement reports (then ANR will insert/update the NRT)
3. RRC queries ANR for NRT content

I'll upload the ANR as a separate patchset when I'm done with it.

Looking forward to your feedback.

Thanks,
-budi-

[Nicola Baldo, 2013-08-10 13:40:25]

Overall the approach is ok, the main issues are to use the templates for the
SAPs and to do some renaming (e.g., prepending "Lte" to class names). See the
detailed comments below.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
File src/lte/model/a2-rsrq-handover-algorithm.cc (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
src/lte/model/a2-rsrq-handover-algorithm.cc:44: class
A2RsrqMemberHandoverManagementSapProvider : public HandoverManagementSapProvider
also this should be replaced by a template, see comment in handover-algorithm.cc

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
File src/lte/model/a2-rsrq-handover-algorithm.h (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
src/lte/model/a2-rsrq-handover-algorithm.h:38: *        on RSRQ and Event A2
(serving cell's RSRQ becomes worse than a
please mention that A4 is used as well.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
src/lte/model/a2-rsrq-handover-algorithm.h:44: class A2RsrqHandoverAlgorithm :
public HandoverAlgorithm
maybe rename to A2A4RsrqHandoverAlgorithm?

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
File src/lte/model/handover-algorithm.cc (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
src/lte/model/handover-algorithm.cc:71: class
BareMemberHandoverManagementSapProvider : public HandoverManagementSapProvider
instead of declaring a separate pair of forwarder classes per each algorithm,
please declare two template forwarder classes for the HandoverManagementSap in
the handover-management-sap.h file, so that this template can be reused for any
handover algorithm.

See lte-rrc-sap.h for an example of the template:
http://lena.cttc.es/hg/lena/file/d9fc1c7ebb10/src/lte/model/lte-rrc-sap.h#l876

and here an example of how it is instantiated:
http://lena.cttc.es/hg/lena/file/d9fc1c7ebb10/src/lte/model/lte-rrc-protocol-...

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
File src/lte/model/handover-algorithm.h (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
src/lte/model/handover-algorithm.h:39: class HandoverAlgorithm : public Object
Please rename to LteHandoverAlgorithm

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
src/lte/model/handover-algorithm.h:70: *        does nothing.
maybe rename it to NoOpHandoverAlgorithm so the name is more meaningful.

I would also consider moving this class to a separate file.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-managem...
File src/lte/model/handover-management-sap.h (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-managem...
src/lte/model/handover-management-sap.h:34: class HandoverManagementSapProvider
please rename to LteHandoverManagementSapProvider

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-managem...
src/lte/model/handover-management-sap.h:58: class HandoverManagementSapUser
please rename to LteHandoverManagementSapUser

https://codereview.appspot.com/12657043/diff/1/src/lte/model/lte-enb-rrc.cc
File src/lte/model/lte-enb-rrc.cc (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/lte-enb-rrc.cc#n...
src/lte/model/lte-enb-rrc.cc:110: class EnbRrcMemberHandoverManagementSapUser :
public HandoverManagementSapUser
also these classes should be replaced by a template, see comment in
handover-algorithm.cc

[buherman, 2013-08-18 19:58:41]

Thanks Nicola for the review. I've updated the code as per your comments.

Regards,
-budi-

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
File src/lte/model/a2-rsrq-handover-algorithm.cc (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
src/lte/model/a2-rsrq-handover-algorithm.cc:44: class
A2RsrqMemberHandoverManagementSapProvider : public HandoverManagementSapProvider
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> also this should be replaced by a template, see comment in
handover-algorithm.cc

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
File src/lte/model/a2-rsrq-handover-algorithm.h (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
src/lte/model/a2-rsrq-handover-algorithm.h:38: *        on RSRQ and Event A2
(serving cell's RSRQ becomes worse than a
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> please mention that A4 is used as well.

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/a2-rsrq-handover...
src/lte/model/a2-rsrq-handover-algorithm.h:44: class A2RsrqHandoverAlgorithm :
public HandoverAlgorithm
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> maybe rename to A2A4RsrqHandoverAlgorithm?

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
File src/lte/model/handover-algorithm.cc (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
src/lte/model/handover-algorithm.cc:71: class
BareMemberHandoverManagementSapProvider : public HandoverManagementSapProvider
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> instead of declaring a separate pair of forwarder classes per each algorithm,
> please declare two template forwarder classes for the HandoverManagementSap in
> the handover-management-sap.h file, so that this template can be reused for
any
> handover algorithm.
> 
> See lte-rrc-sap.h for an example of the template:
> http://lena.cttc.es/hg/lena/file/d9fc1c7ebb10/src/lte/model/lte-rrc-sap.h#l876
> 
> and here an example of how it is instantiated:
>
http://lena.cttc.es/hg/lena/file/d9fc1c7ebb10/src/lte/model/lte-rrc-protocol-...
> 
> 

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
File src/lte/model/handover-algorithm.h (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
src/lte/model/handover-algorithm.h:39: class HandoverAlgorithm : public Object
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> Please rename to LteHandoverAlgorithm

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-algorit...
src/lte/model/handover-algorithm.h:70: *        does nothing.
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> maybe rename it to NoOpHandoverAlgorithm so the name is more meaningful.
> 
> I would also consider moving this class to a separate file.
> 

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-managem...
File src/lte/model/handover-management-sap.h (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-managem...
src/lte/model/handover-management-sap.h:34: class HandoverManagementSapProvider
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> please rename to LteHandoverManagementSapProvider

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/handover-managem...
src/lte/model/handover-management-sap.h:58: class HandoverManagementSapUser
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> please rename to LteHandoverManagementSapUser

Done.

https://codereview.appspot.com/12657043/diff/1/src/lte/model/lte-enb-rrc.cc
File src/lte/model/lte-enb-rrc.cc (right):

https://codereview.appspot.com/12657043/diff/1/src/lte/model/lte-enb-rrc.cc#n...
src/lte/model/lte-enb-rrc.cc:110: class EnbRrcMemberHandoverManagementSapUser :
public HandoverManagementSapUser
On 2013/08/10 13:40:25, Nicola Baldo wrote:
> also these classes should be replaced by a template, see comment in
> handover-algorithm.cc

Done.