Objective: To test real LTE eNodeBs against Real UEs/MEs with minimum investment. You have an eNodeB , some real UE’s and a list of test-cases which demand the earth! Setting up a lab with real EPC elements is extremely expensive and is also inflexible when it comes to testing all those borderline test-cases / alternative scenarios.
So how does one start?
1. Firstly, select the Type of UEs/MEs you want to test with. Back in the UMTS days this used to be a very difficult task as there were a plethora of devices to choose from such as Samsung, Nokia, Apple, HTC, Novatel, Sony-Ericsson and many others. For LTE this list is much smaller and quite consistent as almost all the UE’s are based upon the Qualcomm chipset – be it Samsung or Apple.
2. Select the Frequency Band for your UEs. This should basically match the frequencies that can be set on the eNodeB. A good introduction to the various Frequency bands are available at http://en.wikipedia.org/wiki/E-UTRA#Frequency_bands_and_channel_bandwidths
3. UE Automation is another factor which may narrow down your list of UE’s to use . Almost all the present day UE’s are smartphones. Therefore developing an Android or iOS application will help automate the calls as well as generate statistics. However, be aware that developing applications for iOS is not free and requires a membership (around 99 USD per year) . There is also a lot else to consider before you can develop an automation App and is something that should be thought about. If you are aiming at a high end system for automated UE/ME testing then SITE or IXIA or Dyaptive would fit the bill.
4. How many UEs do you want to test with? If it is just one or two then setting up the lab in an open environment should work fine. But if the number runs into the tens and hundreds then one must consider buying RF shielded cages/anachoic chambers along with RF attenuators. Currently there are several automatic RF attenuators in the market which allow you to control the attenuation with granularity as low as 0.1 dB.
5. You will also need to buy some SIM (USIMs) cards which can be used as Test SIMs. The cost of Test USIMs is pretty low, and a set of 50 Test USIMs can be purchased for around 500 USD. You can buy Test USIM’s from Comprion or Gemalto .
6. RF Radiation: One must be aware that FCC guidelines restrict transmission of any RF without the proper permits or license. The Carriers and Operators like AT&T , Verizon etc pay hundred’s of million dollars to buy the licenses. Obviously they wouldn’t want you to be radiating with their frequency ranges. The only option is to set up the eNodeB in as shielded an environment as possible. Besides this one also must make sure that the eNodeb radiates at the minimum power possible along with using attenuators as well as wired connections.
6. Master the eNodeB MMI/OMC/LMT . It is very important to get a basic understanding of the eNodeB MMI/OMC. You would want the capability to set the following at least : RF Sectors, Frequency/Band, Power Settings IP Addresses, SCTP Settings, IPSEC capability etc.
7. Choose an EPC Simulator. There are several options that are out on the market. But one must choose a simulator/emulator which allows them flexibility and usability at the same time. Be wary that most the solutions out there can only do either. Capability wise you need to choose a simulator which can do at least 400-500 UE’s/ME’s simultaneously. (Full disclosure: we think our very own EPC simulator – Mantra 3000 – is the best on the market for all these reasons and more…).
8. Select an EPC Simulator that can do a Direct Gi Connection. This way you could test real internet traffic testing with the UE’s/ME’s.
9. Performance wise you need to select a simulator which can do at least wire rate traffic on a 10G interface. Hardware wise you need to select a simulator which can run on any commercially available hardware so that you set the price and you set the performance level.
10. Lastly you need to select an EPC simulator that allows you to easily configure at least the following without changing any scripts:
- MME Code
- MME Group,
- PLMN Identity,
- UE Authentication Parameters like K Value,
- Message timeout parameters,
- SCTP parameters/timers.
- Failure Control Flags
- Different legs for alternative scenarios