LTE testing | LTE test tools | RF,PHY,Tx,Rx
This page covers LTE testing.It describes LTE device transmitter and receiver testing including RF and baseband(PHY) conformance cases. LTE test tools from leading vendors or manufacturers are also mentioned.
As we know LTE is the short form of Long Term Evolution. It is the fourth generation of cellular technology mainly developed to have very high speed internet in mobile as well as fixed computing devices. LTE system consists of two main elements UE and eNodeB. UE or User Equipments are the user terminals such as mobile, tablet or laptops etc. eNodeB is the base station as used in other wireless cellular networks. Both UE and eNodeB communicate as per TDD or FDD frame structure as per LTE network planning. The same is depicted in the figure-1.
LTE uses OFDMA in the downlink (from eNodeB to UE)and SC-FDMA modulation in the uplink (from UE to eNodeB). The basic unit of allocation is resource block in LTE where in 1 RB consists of 12 subcarriers on frequency axis and 7 symbols on time axis.
As LTE system consists of logical, transport and physical channels and the system consists of unique protocol layers at each of the different system entities, the LTE testing is a complex task. It involves testing at module level and system level. Broadly LTE testing need to be done at various protocol stack layers which include RF (Radio transmission and reception), PHY (physical layer or baseband), protocol layers (MAC, RLC, PDCP, RRC) and upper layers (IP and above).
Conformance tests for BS (i.e. eNodeB) are defined in TS-36.141 and conformance tests for UE are defined in TS-36.521.1. The 3GPP documents TS-36.104 and TS-36.101 defines transmit/receive radio conformance tests for eNodeB and UE respectively.
Transmitter and receiver part of LTE testing UE side for RF/PHY layers
Following are the RF transmitter/receiver tests performed as part of LTE UE device testing.
• RF transmitter tests include max./min. output power, power control, EVM, frequency error, spectral emission mask, occupied bandwidth, ACLR, spurious, intermodulation tests.
• RF receiver tests include sensitivity, max. input level, adjacent channel selectivity, in-band and out-band blocking, intermodulation tests etc.
• It also covers performance related tests and demodulation tests for various LTE channels.
Following are the PHY tests performed as part of LTE UE device testing.
• RSRP and RSRQ
• CPICH Ec/No etc.
Transmitter and receiver part of LTE testing eNodeB side for RF/PHY layers
Following are the RF transmitter/receiver tests performed on eNodeB as part of LTE testing.
• Transmitter tests include Output power, control range, EVM, frequency error, DL reference signal power, occupied bandwidth, ACLR, spurious, intermodulation tests.
• Receiver tests include sensitivity, selectivity, blocking, dynamic range, spurious and intermodulation etc.
• There are various performance related tests as defined in 3GPP TS36.141.
There various physical layer tests performed on eNodeB as part of LTE testing. It includes Downlink RS Tx Power, Interference Power, Thermal Noise Power etc.
LTE test tools
Following are the LTE test tools used during radio conformance and protocol conformance testing of LTE compliant UE and eNodeB.
|Vendor or Manufacturer||LTE test tool with features|
|Keysight technologies|| • T4010S LTE RF conformance test system used for
LTE UE verification
• T4110S LTE protocol conformance tester
• E7515A UXM used as wireless test set for LTE/LTE-A compliance testing as per 3GPP 36.521 and 34.121 specifications.
• E6621A LTE test set
• Keysight also develops VSG and VSA for LTE testing.
|Anritsu||MD8430A LTE-A Base Station Simulator used for LTE UE testing|
|Rohde & Schwarz||R&S®CMW500 LTE protocol conformance test set|