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# Tutorial on how to perform a intra-frequency X2 Handover (Experimental)
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# Tutorial on how to perform a intra-frequency X2 Handover (Experimental) #
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**Note: for the moment, openair-cn does not yet support the path switch message required for X2 Ho, so to test you need to use a 3rd party EPC**
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## X2 Handover setup
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## X2 Handover setup ##
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The experimentation setups is depicted in figure below and includes 2 OAI eNBs, 2 USRP B210 equipped with the GPS module (daughter board).
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| ... | ... | @@ -21,10 +21,12 @@ The detailed legacy procedure can be found at |
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1. [Analyzing X2 Handover in LTE/LTE-A using OpenAirInterface system emulator] (http://www.eurecom.fr/en/publication/4854/download/comsys-publi-4854.pdf)
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1. [NMC LTE X2 Handover] (http://www.3glteinfo.com/wp-content/uploads/2013/12/NMC.LTE-X2-Handover.v1.0.pdf)
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**Note: eNB X2AP is undergoing development, the first 5 described steps are currently supported in OAI develop branch**
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In the proposed setup, different possible deployed scenarios can be considered for experimentation, e.g., a) different types of traffic (TCP/UDP) in UL/DL, b) successful/failed HO based on UE’s emulated mobility as well as different OAI network measurements, e.g., packet loss, delay, RSRP/RSRQ etc.
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## Attenuator
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In addition, [octoBoxquadAtten](http://www.octoscope.com/English/Products/Ordering/octoBox/quadatten.html) modules are used as attenuators on both the two eNBs to model the user equipment (UE) mobility (fading effects creation) in order to send the A3 event included in its E-UTRAN RRC Measurement report for triggering the HO in the eNB side. Specifically, the selected attenuators offer stable attenuation accuracy via wide choice of attenuation (63 dB range), frequency ranges (DC to 6000 MHz) and step sizes (0.5 step). In addition, the module can be controlled remotely through Ethernet interface (attenuation control unit).
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## Attenuator ##
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In addition, [octoBoxquadAtten](https://www.octoscope.com/English/Products/Ordering/octoBox/OB_QUADATTEN.html) modules are used as attenuators on both the two eNBs to model the user equipment (UE) mobility (fading effects creation) in order to send the A3 event included in its E-UTRAN RRC Measurement report for triggering the HO in the eNB side. Specifically, the selected attenuators offer stable attenuation accuracy via wide choice of attenuation (90 dB range), frequency ranges (DC to 6000 MHz) and step sizes (0.5 step). In addition, the module can be controlled remotely through Ethernet interface (attenuation control unit).
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