laa-wifi-simple scenario configuration and Output Statistics

[DavidCn S.]

Hi All,

I am starting with the interaction of the LBT module, I've been studying the laa-wifi-simple scenario in order to do a better convergence analisys, but I am a little confuse. I have some question about the configuration of the simple scenario, I would appreciate your cordial help.

1. I know that the simple scenario consist of two cells whose radio coverage overlaps but representing two operators in the same region whose transmissions may impact mechanisms such as clear channel assessment and adaptive modulation and coding, the possible cell configurations are Wi-Fi, LTE or LAA. The technologies used are LTE Licensed Assisted Access (LAA) operating on EARFCN 255444 (5.180 GHz), and Wi-Fi 802.11n operating on channel 36 (5.180 GHz)

* this mean that when I configure one cell as LTE or LAA these work in the unlicensed band 5.180 GHz or LTE can have another band configuration over licensed bands, in the             sense that LTE has an anchor in the licensed spectrum and it can provide more bandwidth to the user at disadvantage of WiFi users?

* we suppose that the cell configuration is A-->Wi-Fi and B-->LTE, I would like to know how is made the Channel Access Manager in this configuration, since the LBT (Listen                 Before to Talk) as I understand is implemented only when the cell Configuration is LAA. What happened in this case with the convergence?

2. LAA combines LTE in unlicensed spectrum (5GHz) with LTE in the licensed band through carrier aggregation. Each aggregated carrier is referred to as a component carrier, CC. This aggregation of spectrum provides higher peak data rates as well as better broadband experience across the coverage area for a fatter pipe with a more responsive user experience. Knowing this I wolud like to know if the carrier aggregation is implemented in the LBT Wi-Fi Coexistence Module, if so where and how work this?

3. The simulator is instrumented to log and Classify:

* All PHY layer transmissions: Through a logfile of signal arrivals to physical layer,

this logfile provide the following information:

time(s) --> time in which the User receives a packet at physical layer

nodeId --> ID number to identify which user node is arriving the packet 

type --> what kind of network the packet comes from (LTE or Wi-Fi)

sender --> ID number to identyfy the BS or eNB who is send the packet

endTime(s) --> time in which finish the packet reception 

duration(ms) --> time duration of the packet reception 

powerDbm --> the arrival signal strength in dBm

When I simulate the laa-wifi-simple scenario with only one cell for the operator A and one for the operator B in this physical statistics I've obtained different values of sender in the case of CellConfig of Wi-Fi, for example the operator B is configured as LTE with a sender ID of 1 while the operator B is configured as Wi-Fi it is assumed that the Sender ID be 0 due to to that I only have 1 cell, but some time the value is 0 and some times is different why this happen? This is possible see it also in the retransmission log.

#time(s) nodeId type sender endTime(s) duration(ms)     powerDbm

2.006214286 42  lte 1 2.006999999 0.785713000 -79.646800130

2.006214286 43  lte 1 2.006999999 0.785713000 -58.677700000

2.006214286 44  lte 1 2.006999999 0.785713000 -79.902300220

2.006214286 45  lte 1 2.006999999 0.785713000 18.000000000

2.006214286 46  lte 1 2.006999999 0.785713000 -79.646800130

2.006214286 47  lte 1 2.006999999 0.785713000 -58.677700000

2.006214286 48  lte 1 2.006999999 0.785713000 -79.902300220

2.006214286 49  lte 1 2.006999999 0.785713000 18.000000000

2.006214286 50  lte 1 2.006999999 0.785713000 -79.646800130

2.006214286 51  lte 1 2.006999999 0.785713000 -58.677700000

2.006214286 1  lte 1 2.006999999 0.785713000 23.000000000

2.007354361 0 wifi 38 2.007398361 0.044000000 -53.677700000

2.007354361 2 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 3 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 4 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 5 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 6 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 7 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 8 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 9 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 10 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 11 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 12 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 13 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 14 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 15 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 16 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 17 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 18 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 19 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 20 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 21 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 22 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 23 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 24 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 25 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 26 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 27 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 28 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 29 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 30 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 31 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 32 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 33 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 34 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 35 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 36 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 37 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 39 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 40 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 41 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 42 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 43 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 44 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 45 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 46 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 47 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 48 wifi 38 2.007398361 0.044000000 -63.677700000

2.007354361 49 wifi 38 2.007398361 0.044000000 -84.646800130

2.007354361 50 wifi 38 2.007398361 0.044000000 13.000000000

2.007354361 51 wifi 38 2.007398361 0.044000000 -84.902300220

2.007354361 1 wifi 38 2.007398361 0.044000000 -79.646800130

2.007414361 2 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 3 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 4 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 5 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 6 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 7 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 8 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 9 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 10 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 11 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 12 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 13 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 14 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 15 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 16 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 17 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 18 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 19 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 20 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 21 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 22 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 23 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 24 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 25 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 26 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 27 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 28 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 29 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 30 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 31 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 32 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 33 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 34 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 35 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 36 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 37 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 38 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 39 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 40 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 41 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 42 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 43 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 44 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 45 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 46 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 47 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 48 wifi 0 2.007442361 0.028000000 23.000000000

2.007414361 49 wifi 0 2.007442361 0.028000000 -74.902300220

2.007414361 50 wifi 0 2.007442361 0.028000000 -53.677700000

2.007414361 51 wifi 0 2.007442361 0.028000000 -74.646800130

2.007414361 1 wifi 0 2.007442361 0.028000000 -69.902300220

2.007518361 2 wifi 0 2.007624499 0.106138000 -53.677700000

2.007518361 3 wifi 0 2.007624499 0.106138000 -74.646800130

2.007518361 4 wifi 0 2.007624499 0.106138000 23.000000000

2.007518361 5 wifi 0 2.007624499 0.106138000 -74.902300220

2.007518361 6 wifi 0 2.007624499 0.106138000 -53.677700000

2.007518361 7 wifi 0 2.007624499 0.106138000 -74.646800130

2.007518361 8 wifi 0 2.007624499 0.106138000 23.000000000

2.007518361 9 wifi 0 2.007624499 0.106138000 -74.902300220

2.007518361 10 wifi 0 2.007624499 0.106138000 -53.677700000

2.007518361 11 wifi 0 2.007624499 0.106138000 -74.646800130

2.007518361 12 wifi 0 2.007624499 0.106138000 23.000000000

2.007518361 13 wifi 0 2.007624499 0.106138000 -74.902300220

2.007518361 14 wifi 0 2.007624499 0.106138000 -53.677700000

2.007518361 15 wifi 0 2.007624499 0.106138000 -74.646800130

2.007518361 16 wifi 0 2.007624499 0.106138000 23.000000000

2.007518361 17 wifi 0 2.007624499 0.106138000 -74.902300220

2.007518361 18 wifi 0 2.007624499 0.106138000 -53.677700000

2.007518361 19 wifi 0 2.007624499 0.106138000 -74.646800130

2.007518361 20 wifi 0 2.007624499 0.106138000 23.000000000

2.007518361 21 wifi 0 2.007624499 0.106138000 -74.902300220

2.007518361 22 wifi 0 2.007624499 0.106138000 -53.677700000

2.007518361 23 wifi 0 2.007624499 0.106138000 -74.646800130

4. In this last question I want that correct me if I’m wrong. When I analyze the DataTx output statistic I saw that the time duration of the transmission is 0, this is why we are in a simulation environment or instead we should see a value of time duration

Thanks for your help in advance...

[Tom Henderson]

On 05/03/2017 06:30 AM, DavidCn S. wrote:

Hi All,

I am starting with the interaction of the LBT module, I've been studying the laa-wifi-simple scenario in order to do a better convergence analisys, but I am a little confuse. I have some question about the configuration of the simple scenario, I would appreciate your cordial help.

1. I know that the simple scenario consist of two cells whose radio coverage overlaps but representing two operators in the same region whose transmissions may impact mechanisms such as clear channel assessment and adaptive modulation and coding, the possible cell configurations are Wi-Fi, LTE or LAA. The technologies used are LTE Licensed Assisted Access (LAA) operating on EARFCN 255444 (5.180 GHz), and Wi-Fi 802.11n operating on channel 36 (5.180 GHz)

* this mean that when I configure one cell as LTE or LAA these work in the unlicensed band 5.180 GHz or LTE can have another band configuration over licensed bands, in the             sense that LTE has an anchor in the licensed spectrum and it can provide more bandwidth to the user at disadvantage of WiFi users?

The simulations only consider the unlicensed downlink, not the licensed component.

* we suppose that the cell configuration is A-->Wi-Fi and B-->LTE, I would like to know how is made the Channel Access Manager in this configuration, since the LBT (Listen                 Before to Talk) as I understand is implemented only when the cell Configuration is LAA. What happened in this case with the convergence?

The 'LTE' mode in this case is a duty-cycled LTE.  It is not the same as LTE-U but is a first step towards such a model (since it allows for configurable duty cycling of LTE transmissions).  If no duty cycle is configured, it can operate like traditional LTE but in the unlicensed band (where it does not coexist well with Wi-Fi in such a case).

2. LAA combines LTE in unlicensed spectrum (5GHz) with LTE in the licensed band through carrier aggregation. Each aggregated carrier is referred to as a component carrier, CC. This aggregation of spectrum provides higher peak data rates as well as better broadband experience across the coverage area for a fatter pipe with a more responsive user experience. Knowing this I wolud like to know if the carrier aggregation is implemented in the LBT Wi-Fi Coexistence Module, if so where and how work this?

No, carrier aggregation model has recently been added to ns-3-dev, but the LAA code has not been updated.  Only the non-aggregated unlicensed carrier is simulated.  It may be that there is some form of cross-carrier scheduling in practice, but the current models do not support this.

3. The simulator is instrumented to log and Classify:

* All PHY layer transmissions: Through a logfile of signal arrivals to physical layer,

this logfile provide the following information:

time(s) --> time in which the User receives a packet at physical layer

nodeId --> ID number to identify which user node is arriving the packet 

type --> what kind of network the packet comes from (LTE or Wi-Fi)

sender --> ID number to identyfy the BS or eNB who is send the packet

endTime(s) --> time in which finish the packet reception 

duration(ms) --> time duration of the packet reception 

powerDbm --> the arrival signal strength in dBm

When I simulate the laa-wifi-simple scenario with only one cell for the operator A and one for the operator B in this physical statistics I've obtained different values of sender in the case of CellConfig of Wi-Fi, for example the operator B is configured as LTE with a sender ID of 1 while the operator B is configured as Wi-Fi it is assumed that the Sender ID be 0 due to to that I only have 1 cell, but some time the value is 0 and some times is different why this happen? This is possible see it also in the retransmission log.

The below log is not consistent with laa-wifi-simple, which only has four nodes.  That trace shows 51 nodes.  I am not sure which one it corresponds to (the indoor scenario node numbering typically stops at 47).

In laa-wifi-simple, the nodes 0 and 1 are the BS/enB nodes, and 2 and 3 are the STA/UE nodes.  In laa-wifi-indoor, the nodes 0-7 are BS/eNB and 28-47 are the STA/UE nodes.

DataTx holds a timestamp, not a duration.  A value of 0 would correspond to simulation time 0.

struct DataTx
{
  Time m_time;
  uint32_t m_nodeId;
  uint32_t m_size;
};

[DavidCn S.]

Thank you for your prompt response !!

In the third question that I done, I am sure that the obtained log is from the laa-wifi-simple scenario called laa_wifi_simple_default_phy_log. But due to response I don't know if the configuration that I am using is possible. I know that by default the scenario is configured with 

  bsNodesA.Create (1);

  bsNodesB.Create (1);

  ueNodesA.Create (1);  

  ueNodesB.Create (1);

For this reason, you said me that in laa-wifi-simple, the nodes 0 and 1 are the BS/enB nodes, and 2 and 3 are the STA/UE nodes. But, I am trying to simulate a high number of user STA/UE so, I put the CellConfigA --> Wi-Fi and CellConfigB --> LAA and I have increased the user node change the configuration as follow, with a transport method FTP and the other parameters by defaul  

  bsNodesA.Create (1);

  bsNodesB.Create (1);

  ueNodesA.Create (50);  

  ueNodesB.Create (20);

Really, I don't know if doing this is wrong. I hope leave the doubt by this clarification, 

I Attach the total output log in order to have a better understanding

Thanks for your help in advance...

3. The simulator is instrumented to log and Classify: