## External USIM¶

Using an actual SIM card to authenticate the user against the network is an advanced feature. It requires a SIM card reader attached to the PC running srsUE that is supported by PCSClite.

Before using a SIM card, please make sure to disable PIN activation using a regular phone.

In order to compile srsUE with support for it, the pcsclite development headers as well as the pcsc daemon need to be installed and running. On Ubuntu (or other Debian derivates), this can be done with:

sudo apt-get install libpcsclite-dev pcscd pcsc-tools


After this is done, please verify you’ve got a PCSC-compatible reader by running ‘pcsc_scan’.

Now, CMake should pick up the pcsc libraries and build the support code for it. If that is not the case, try with a clean build folder or remove your exisiting CMakeCache.txt:

$cmake .. ... -- PCSC LIBRARIES: /usr/lib/x86_64-linux-gnu/libpcsclite.so -- PCSC INCLUDE DIRS: /usr/include/PCSC -- Building with PCSC support. ...$ make


After the build is complete, you can verify the correct operation with the pcsc_usim_test application. Please verify that the IMSI can be read from the card:

$./srsue/test/upper/pcsc_usim_test .. 09:06:36.064073 [USIM] [D] SCARD: MNC length=2 09:06:36.064079 [USIM] [D] MNC length 2 IMSI: 21XXXXXXXXXXXX 09:06:36.064095 [USIM] [D] SCARD: UMTS auth - RAND 0000: bc 4c b0 27 b3 4b 7f 51 21 5e 56 5f 67 3f de 4f 09:06:36.064102 [USIM] [D] SCARD: UMTS auth - AUTN 0000: 5a 17 77 3c 62 57 90 01 cf 47 f7 6d b3 a0 19 46 09:06:36.064107 [USIM] [D] SCARD: scard_transmit: send 0000: 00 11 00 81 22 10 bc ac b1 17 13 4b 6f 51 21 5e 0010: 47 47 6d b3 a0 19 46 09:06:36.119675 [USIM] [D] SCARD: SCardTransmit: recv 0000: 98 62 09:06:36.119707 [USIM] [D] SCARD: UMTS alg response 0000: 98 62 09:06:36.119717 [USIM] [W] SCARD: UMTS auth failed - MAC != XMAC 09:06:36.119725 [USIM] [E] SCARD: Failure during USIM UMTS authentication 09:06:36.119732 [USIM] [D] SCARD: deinitializing smart card interface  If those steps completed successfully we can now start srsUE by either enabling the PCSC USIM in the config file or by passing the option as an command line argument, e.g., run: $ ./srsue/src/srsue --usim.mode=pcsc


## Channel Emulator¶

The channel emulator can be enabled and disabled with the parameter channel.dl.enable.

[channel]
dl.enable = true
...


As mentioned above, the channel emulator can simulate fading channels. It supports 4 different models:

• none: single tap with no delay, doppler dispersion can be applied if specified.
• epa: Extended Pedestrian A, described in 3GPP 36.101 Section B.2.1
• eva: Extended Vehicular A model, described in 3GPP 36.101 Section B.2.1
• etu: Extended Typical Urban model, described in 3GPP 36.101 Section B.2.1

The fading emulator has two parameters: enable and model. The parameter model is the channel model mentioned above, followed by the maximum Doppler dispersion (e.g. eva5). The following example enables the fading submodule with a EVA fading model and a maximum doppler dispersion of 5 Hz.

...
...


The delay simulator generates the delay according to the next formula:

$d(t) = delay.minimum_us + (delay.maximum_us - delay.minimum_us) * (1.0 + sin(2*pi*t/delay.period)) / 2.0$

Where delay.minimum_us and delay.maximum_us are specified in microseconds while delay.period must be in seconds.

Hence, the maximum simulated speed is given by:

$v_max = (delay.maximum_us - delay.minimum_us) * pi * 300 / delay.period$

The following example enables the delay simulator for having a period of 1h with a minimum delay of 10 microseconds and a maximum delay of 100 microseconds:

...
dl.delay.enable     = true
dl.delay.period     = 3600
dl.delay.maximum_us = 100
dl.delay.minimum_us = 10
...


• on: the UE receives baseband signal, unaffected by the simulator.
• off: the UE does not receive any signal, the simulator substitutes the baseband with zeros.

The time the emulator spends in on is parametrized by rlf.t_on_ms and rlf.t_off_ms for off. Both parameters are expected to be in milliseconds.

The following example enables the RLF simulator for having 2 seconds of blackout every 10 seconds of full baseband signal:

...
dl.rlf.enable       = true
dl.rlf.t_on_ms      = 10000
dl.rlf.t_off_ms     = 2000
...


## MIMO¶

The srsUE supports MIMO operation for transmission modes 1, 2, 3 and 4. The user can select the number of select antennas in the ue.conf:

...
[rf]
...
nof_rx_ant = 2
...


Do you want to attach to a 2 port eNb and you have only one receive channel? No problem. The UE can attach to 2 port cell and be in TM3 or TM4 without having a second receive antenna. Nevertheless, it will not take advantage of spatial multiplexing and it will not achieve the maximum throughput.

Warning

TBA