D2D implemented in HetNets

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  • #5896
    Nguyen Le Hung

    Dear community,

    I’m trying to use Vienna LTE system level simulator r885 to implement a simulation scenario which includes multi layers: macro cell, small cells, and D2D communication to evaluate the interference of D2D communication on cellular communication and vice versa.

    Small cells have been supported in current source code, however, D2D has not been implemented yet.
    As far as I understand, there are two most important parts should be done:
    1. creating the connection between 2 UE
    2. calculating the SINR with the coexistence of cellular communication and D2D communication.

    I would like to ask some following questions:
    1. Which part of the source code should I focus on to create the connection between two users
    2. D2D communication and Cellular Communication will leave interference on each other if they share the same resource block (time and frequency). Which part should I modify to share the radio resource of Cellular Communication to D2D Communication ?

    Any suggestion or documents are appreciated.

    Thank you


    Dear LeHung,

    each user (+network_element/UE.m) has the properties attached_site, attached_sector_idx and attached_eNodeB. You may want to add properties here.
    The sharing of the radio resources is taken into account in the link quality model of the UE; see functions link_quality_model_v1 and link_quality_model_v2 in +network_elements/UE.m.

    Best regards,

    Nguyen Le Hung

    Dear Dr. Martin Taranetz,

    Thank you very much for your reply !

    Firstly, I would like to imitate the method of how to “create the connection between eNodeB and UE” to “create the connection between UE and UE”.

    As far as I’ve read in source code, the basic procedure to create the connection between an eNodeB and an UE is as follows:

    1. The UE positions will be randomly generated in “LTE_init_generated_users_and_schedulers.m”

    2. From the UE position, UE will be assigned to “attached_site”

    3. UE then will be attached to an eNodeB based on distance (or SINR ?)
    in “LTE_init_generated_users_and_schedulers.m” & “eNodeB_sector.m”

    4. Next, UE will be put in the scheduler’s queue of that eNodeB, and the Resource Block of this eNodeB will be assigned to this UE.
    The number of Resource Block will be assigned to UE depends on the Resource Allocation scheme (Round Robin, Proportional Fair…)
    in “UE.m”

    5. Based on the number of Resource Blocks are assigned to that UE, eNodeB will decide the power allocation for that UE.
    For example, the total power of eNodeB is 40W which will be divided for 100 Rbs → each Resource Block is transmitted with power = 0.4W
    If the UE is assigned with 5 RB → the Tx power for that UE is 2W
    in “UE.m”

    6. The total Pathloss is calculated in “downlinkChannelModel.m”. The pathloss is determined from (UE positions, eNodeB positions)

    7. From the “Tx Power” and “Pathloss”, we can determine the Received Signal’s power in UE side.

    I would like to create the connection between 2 Ues, and my idea is to imitate from step 5, 6, 7.
    first, I would assume the Tx Power in Tx UE, then use the function to calculate the Pathloss based on 2 UE’s position.

    However, I am not sure this is a good approach or not ? Is there anything else that should be considered. Any suggestion is appreciated.

    Thank you


    Dear LeHung,

    3. It will be attached according to max SINR.

    5. exactly

    Please be aware that the system level-simulator is downlink-only. You could specify the properties of an eNodeB such that it imitates a user. If you want to have a macro-network with underlying UE-to-UE connections, you can imitate this by adding small cells (your “transmitting users”), and specify the small cell parameters according to the desired UE specs.

    Best regards,

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