ns-3 GSoC 2013 (LTE) - Proposed merge

Hi,

This is the standard set of deliverables of the ns-3 GSoC 2013 project, LTE UE measurements. It includes:
 - the latest lena-dev repository (revision 10195 as the tip, dated Friday 13th of September);
 - ns-3-dev changes up to revision 10192 (dated Friday 6th of September); and
 - all the changes made by the project from the beginning until the pencil-down week (up to Monday 16th of September).

=== UPDATE (25th of September). Added Patch Set 2, which is the final set of deliverables of the project. It's based on revision 10205 of ns-3-dev [1] and revision 10059 of GSoC repository [2]. If you want to download it, please clone it directly from the merged repository [3] where this patch set originates from.

=== UPDATE (23rd of October). Added Patch Set 3, which is a merge of ns-3-dev revision 10224 and GSoC repository revision 10074. This includes the result of the final code review [4].

The aim of the review is to merge the deliverables to ns-3-dev and lena-dev repository. For reviewing purpose, please also check another Rietveld issue [4] which is intended for a more convenient review.

The patch set below contains a lot of files, which I'll briefly introduce here. The files under `src/lte/doc/` are related to the updated LTE model library documentation text (*.rst) and figures (*.dia, *.eps, *.dot, *.png, *.pdf). The compiled version are also available for review in HTML [5] and PDF [6] formats. The most relevant sections for the project are:
 - Design Documentation > RRC > Initial Cell Selection;
 - Design Documentation > RRC > UE RRC Measurements Model;
 - Design Documentation > RRC > Handover;
 - Design Documentation > RRC > Neighbour Relation;
 - User Documentation > Network Attachment;
 - User Documentation > Configure UE measurements;
 - User Documentation > X2-based handover;
 - User Documentation > Reference scenarios > Handover simulation campaign;
 - Testing Documentation > UE measurement configuration tests;
 - Testing Documentation > Initial cell selection; and
 - Testing Documentation > Selection of target cell in handover algorithm.

The files under `src/lte/model/` are the main code. In overview, these files can be grouped as follows:
 - related to UE measurements function:
    - lte-rrc-sap.* (data types)
    - lte-common.* (conversion functions)
    - lte-enb-rrc.*
    - lte-ue-rrc.*
 - related to System Information Block Type 1 (SIB1):
    - lte-control-messages.* (message type)
    - lte-enb-rrc.*
    - lte-enb-cphy-sap.* (RRC-PHY interface)
    - lte-enb-phy.*
    - lte-rrc-protocol-ideal.* (old RRC-RRC interface)
    - lte-rrc-protocol-real.* (old RRC-RRC interface)
    - lte-rrc-sap.* (new RRC-RRC interface)
    - lte-ue-cphy-sap.* (PHY-RRC interface)
    - lte-ue-rrc.*
 - related to Idle mode initial cell selection function:
    - lte-rrc-sap.* (data types)
    - epc-ue-nas.*
    - lte-as-sap.* (NAS-RRC interface)
    - lte-ue-cphy-sap.* (RRC-PHY interface)
    - lte-ue-phy.* (cell search)
    - lte-ue-rrc.*
 - related to Handover Algorithm function:
    - lte-handover-algorithm.* (base class)
    - a2-a4-rsrq-handover-algorithm.* (legacy)
    - a3-rsrp-handover-algorithm.* (strongest cell)
    - no-op-handover-algorithm.* (disable handover algorithm)
    - lte-handover-management-sap.* (interface with RRC)
    - lte-enb-rrc.*
    - lte-enb-net-device.*    
 - related to Automatic Neighbour Relation (ANR) function:
    - lte-anr-sap.* (interface with RRC)
    - lte-anr.* (ANR)
    - lte-enb-rrc.*
    - lte-enb-net-device.*
 
The remaining files are helpers, examples, and tests:
 - lena-dual-stripe.cc (updated with initial cell selection)
 - lena-x2-handover-measures.cc (updated with handover algorithm)
 - lte-test-cell-selection.* (a test suite for initial cell selection)
 - lte-test-ue-measurements.* (3 new test suites related to UE measurements)
 - test-lte-handover-target.cc (a test suite for handover algorithm)
 - test-lte-x2-handover-measures.cc (updated with handover algorithm)

Issue to note: some test results have indicated that when RRC connection establishment messages are lost, they are not re-transmitted. Hence the UE stays in IDLE_CONNECTING state forever. This is probably a bug and is currently under investigation.

=== UPDATE (17th September 2013). The above issue has become Bug 1762 [7].

Thanks for spending the time for reviewing.

-budi-

[1] http://code.nsnam.org/ns-3-dev/
[2] http://code.nsnam.org/buherman/ns-3-gsoc-lte/
[3] http://code.nsnam.org/buherman/ns-3-gsoc-lte-merge/
[4] https://codereview.appspot.com/13720052/
[5] http://www.nsnam.org/~buherman/sphinx_gsoc2013/html/lte.html
[6] http://www.nsnam.org/~buherman/sphinx_gsoc2013/latex/ns-3-model-library.pdf
[7] https://www.nsnam.org/bugzilla/show_bug.cgi?id=1762