GitLab

changes in lmslib.cpp

small fix for mbmssim (a previous commit enabled XFORMS by default, which was not up to date in mbmssim)

handling of timing advance is improved. MAC retrieves timing advance from phy once prior to DL scheduling and clears the statistic in PHY. A timer for controlling the timing advance periodicity was introduced.

Tested modifications for 23.04 Ms/s 100 PRB transmission/reception (Downlink).  This will reduce I/Q acquisition times for 20 MHz channels.  new option in dlsim (-E) for testing 1536-point DFT instead of 2048 for this lower sampling rate. Added normalization to idft1536.  Should also be added to dft1536 later.

Limitation of non SI DLSCH allocations in subframe 0/5 to PRBS not around DC (avoid puncturing from PBCH). Placement of SI around DC instead of randomized allocations. Placement of RA allocations at PRB 0-3.  Tested DL throughput on 5 MHz to 16 Mbit/s in TM1.

Added DLSCH scheduling for subframes 0 and 5. Changes in MAC scheduling data structure to keep track of VRB allocations from SI,RA when scheduling regular DLSCH

CCE Allocation in MAC, rebase from develop. Frame number limitation to 1024 for non-real time targets (caused bad bug in oaisim).

The oldest PID (the PID that was used the longest
TTI ago) is at the head and is the next one that
will be used.

No test is done to check that when a process is
allocated it is at least N TTIs old, but some quick
thinking strongly leads to the 'conclusion' that N
won't be smaller than 8, which seems to be what
cat3 UEs require to function properly in the downlink
direction (from the eNodeB to the UE).

The problem seems that we reuse HARQ processes too early.
For example, at subframe 0 we allocate PID 0. At subframe 4
we receive an ACK. At subframe 5 we may well reallocate this
PID. It seems category 3 UEs don't like that. They expect
some delay. How much? I don't know. 8 maybe, as for UL.

This commit forces allocation of HARQ PID:
  0 on subframe 1,
  1 on subframe 2,
  2 on subframe 3,
  3 on subframe 4,
  4 on subframe 6,
  5 on subframe 7,
  6 on subframe 8,
  7 on subframe 9.

We don't use subframes 0 and 5 (for initial transmission at
least). (Current develop branch doesn't either I think.)

This is not a good solution, just a quick and dirty one. With this
commit I can achieve 12Mbps with iperf UDP on a 5MHz band 7 carrier
with a cat3 UE. And more than 11Mbps with iperf TCP. And a bad
radio link.

We may want to implement some sort of free-list and take the
oldest PID in there, if it is older than let's say 8 subframes
(that is: the last transmission with this pid was done more
than 8 subframes ealier). We may well have no free PID if a
lot of retransmissions are done.

adding perfect_ce to mbmssim

adding error checks in dlsim