Comparison of Battery Life Performance of VoLTE Capable Devices

Comparison of Battery Life Performance of VoLTE Capable Devices Date: 02/11/2013 Document Version Number: 1.0 Author: Ardeshir Ghanbarzadeh Manager, Product Management

SPIRENT 7340 Executive Way, Suite A Frederick, MD 21704 Email: sales@spirent.com Web: http://www.spirent.com Americas 1-800-SPIRENT +1-818-676-2683 sales@spirent.com Europe and the Middle East +44 (0) 1293 767979 emeainfo@spirent.com Asia and the Pacific +86-10-8518-2539 salesasia@spirent.com 2013 Spirent. All Rights Reserved. All of the company names and/or brand names and/or product names referred to in this document, in particular, the name Spirent and its logo device, are either registered trademarks or trademarks of Spirent plc and its subsidiaries, pending registration in accordance with relevant national laws. All other registered trademarks or trademarks are the property of their respective owners. The information contained in this document is subject to change without notice and does not represent a commitment on the part of Spirent. The information in this document is believed to be accurate and reliable; however, Spirent assumes no responsibility or liability for any errors or inaccuracies that may appear in the document.

Table of Contents Comparison of Battery Life Performance of VoLTE Capable Devices A Case Study... i 1. Abstract... 2 2. Case Study overview... 2 3. Test Procedure... 2 3.1. Test Locations... 2 3.2. Test Equipment & Methodology... 2 3.2.1. Key Performance Indicators... 3 3.2.2. Device Settings & Configuration... 3 4. Test Results... 4 4.1. CDMA Voice Calls... 4 4.2. Voice over LTE (VoLTE) Calls... 6 4.3. Voice over IP (VoIP) Calls Using Skype on LTE... 9 4.4. Simultaneous voice & data calls... 11 5. Conclusion... 13 I

1. ABSTRACT With the introduction of new mobile technologies to support the market demand for voice and data, operators are moving in the direction of introducing packetized voice services over the mobile data networks. A new rollout of voice technology over the mobile broadband LTE network referred to as Voice over LTE or VoLTE is currently being offered commercially by MetroPCS. MetroPCS currently offers two smartphones manufactured by LG Electronics capable of supporting VoLTE service. The objective of this study is to measure and quantify the impact on the devices battery life performance for voice calls placed over CDMA and VoLTE networks and compare the results from across the two generations of this device platform. 2. CASE STUDY OVERVIEW The study was conducted in the Dallas metro market of US operator MetroPCS using the first VoLTE supported device; the LG MS840 commercially known as the LG Connect 4G, and the second implementation of this platform, the LG MS870 commercially known as the LG Spirit 4G smartphones. Both devices are capable of supporting both CDMA and VoLTE voice calling. drain and power consumption samples were collected at multiple locations in this market for CDMA and VoLTE calls, as well as multi-service CDMA/LTE and VoLTE/LTE simultaneous voice and data calls. Also tested was Voice over IP (VoIP) calls using Microsoft s Skype over-the-top Android application over the LTE data network. The mean values of respective samples, as well as the capacity of the devices batteries were used to determine battery life estimations. Device Profiles Properties LG Connect 4G LG Spirit 4G Battery Capacity 1540 mah 2150 mah Model Number LG MS840 LG MS870 Operating System Android 2.3 Android 4.0 Processor 1.2 GHz processor 1.2 GHz Dual-core processor Display Size 4.0-inch screen 4.5-inch screen Published talk time Battery Life Up to 270 Minutes Up to 420 Minutes 3. TEST PROCEDURE 3.1. Test Locations All tests were performed in stationary locations. Tests were performed at two separate locations with RF signal strength of approximately -75 dbm. All tests were performed in Dallas, Texas. 3.2. Test Equipment & Methodology For the voice call only test in both CDMA and VoLTE, the native dialer of the device was used to establish a call to Spirent s voice server providing simulated speech. Each device was first configured according to the parameters identified in Table 1 of this document. The device display was turned off during testing and measurements were taken using a Monsoon Power Monitor acting as the source and test point. Five samples 2

of approximately 10 minutes in duration were collected at each of two locations and current drain and power consumption was measured for each sample. The average value of all ten (10) samples was used to represent current and power measurements, and in calculating the estimated battery life. For Skype VoIP calls, a voice call was placed to Spirent s voice server over the LTE data network using the Skype application. The device display was turned off and five samples of approximately 10 minutes in duration were collected at each of the two test locations. The average value of all ten (10) samples was used to represent current and power measurements, and in calculating the estimated battery life. For the simultaneous voice and data tests, Spirent s Datum Mobile application was used to establish a simultaneous voice and data call. Using Spirent s Datum Mobile, a multi-service session is established by initiating a file download from a data server, and a voice call was established with the data download in progress for a two-minute period. drain and power consumption measurements were taken for the multi-service session. Five samples were taken at each location and the average value of all ten samples was used to represent current and power measurements used to calculate estimated battery life. 3.2.1. Key Performance Indicators The Key Performance Indicators (KPIs) for all tests include: - current drain in milliamps and standard deviation. - power consumption in milliwatts and standard deviation. - Estimated battery life in minutes. 3.2.2. Device Settings & Configuration Each Device Under Test (DUT) was configured with the following parameters prior to testing in all test sets and at all test locations: Parameter Applicable Test Case Value Screen Brightness Multi-Service 100% or MAX Screen Timeout Multi-Service Never/Max Allowed Screen Auto-Brightness Multi-Service Disabled Wi-Fi Radio Multi-Service / Voice Call Only Enabled Wi-Fi Connection Multi-Service / Voice Call Only Not Connected Mobile Data Multi-Service / Voice Call Only Enabled Bluetooth Radio Multi-Service / Voice Call Only Disabled Bluetooth Connection Multi-Service / Voice Call Only Disabled Background Data Multi-Service / Voice Call Only Enabled Volume Level Multi-Service / Voice Call Only Maximum GPS Radio Multi-Service / Voice Call Only Disabled Browser Cache Multi-Service Clear prior to each sample Browser History Multi-Service Clear prior to each sample Browser Cookies Multi-Service Clear prior to each sample Table 1 - Device Configuration Parameters 3

4. TEST RESULTS 4.1. CDMA VOICE CALLS When placing voice calls over the CDMA network, the average current drain of the first generation device, the LG Connect 4G, across all samples was measured at 185 ma. The average current drain across all samples for the second implementation device, the LG Spirit 4G, was measured at 151 ma. This represents an 18% improvement in current drain on the LG Spirit 4G over the LG Connect 4G for CDMA voice calls. As noted in the device profile section of this report, the more recently released LG Spirit 4G also includes a 2150 mah battery which is a 38% improvement in total battery capacity over the LG Connect 4G. As a result of the combination of the improvements in current drain and the additional battery capacity, there is approximately a 75% improvement in overall battery life for CDMA voice calls on the LG Spirit 4G compared to the LG Connect 4G. Sampling Information LG Connect 4G LG Spirit 4G Average Time Per Call Cycle 601 Seconds 605 Seconds Number of Call Cycles 10 Cycles 10 Cycles Total Number of Seconds Sampled 6013 Seconds 6048 Seconds Instantaneous Power Sampling Rate 5000 Samples/Second 5000 Samples/Second Total Number of Instantaneous Measurements 30,240,000 Samples 30,065,000 Samples TABLE 2- VOICE CALL DURATIONS AND SAMPLING INFORMATION FIGURE 1 CDMA VOICE CALL SUMMARY RESULTS 4

Device Under Test (Voice Service Type) Power Consumption Power Drain (ma) Estimated Battery Life (Minutes) LG Connect 4G (CDMA) 685 24.9 185 6.7 499.0 LG Spirit 4G (CDMA) 560 48.8 151 13.5 875.0 TABLE 3- CDMA VOICE CALL SUMMARY RESULTS FIGURE 2 - CURRENT DRAIN MEASUREMENTS FOR CDMA CALLS 5

Device Under Test LG Connect 4G (CDMA) Stationary Locations Location 1 Test Cycle Power Consumption Drain (ma) Session Duration (Seconds) Cycle 1 640 173 608 Cycle 2 671 181 610 Cycle 3 710 192 600 Cycle 4 688 186 614 Cycle 5 723 196 601 Cycle 1 698 189 625 Cycle 2 680 184 580 (ma) Power Estimated Battery Life (Minutes) 185 685 6.7 499.0 LG Spirit 4G (CDMA) Location 2 Location 1 Location 2 Cycle 3 659 178 611 Cycle 4 704 190 593 Cycle 5 678 183 571 Cycle 1 669 179 602 Cycle 2 534 143 600 Cycle 3 523 140 603 Cycle 4 513 137 775 Cycle 5 516 138 571 Cycle 1 555 149 600 Cycle 2 529 143 580 Cycle 3 588 159 582 Cycle 4 583 159 565 Cycle 5 592 161 570 151 560 13.5 875.0 TABLE 4- MEASUREMENTS FOR CDMA VOICE CALLS 4.2. VOICE OVER LTE (VOLTE) CALLS When placing voice calls over the VoLTE network, the average current drain of the first generation device, LG Connect 4G, across all samples was measured at 356 ma. The average current drain across all samples for the second implementation device, the LG Spirit 4G, was measured at 232 ma. This represents a 35% improvement in current drain on the LG Spirit 4G over the LG Connect 4G for VoLTE calls. As noted in the device profile section of this report, the most recently released LG Spirit 4G also includes a 2150 mah battery which is a 38% improvement in battery capacity over the LG Connect 4G. As a result of the combination of the improvements in current drain and the additional battery capacity, there is an approximate 122% improvement in overall battery life for VoLTE calls on the LG Spirit 4G compared to the LG Connect 4G. 6

Sampling Information LG Connect 4G LG Spirit 4G Average Time Per Call Cycle 564 Seconds 606 Seconds Number of Call Cycles 10 Cycles 10 Cycles Total Number of Seconds Sampled 5640 Seconds 6064 Seconds Instantaneous Power Sampling Rate 5000 Samples/Second 5000 Samples/Second Total Number of Instantaneous Measurements 28,200,000 Samples 30,320,000 Samples TABLE 4- VOICE CALL DURATIONS AND SAMPLING INFORMATION FIGURE 3 VOLTE VOICE CALL SUMMARY RESULTS Device Under Test (Voice Service Type) Power Consumption Power Drain (ma) Estimated Battery Life (Minutes) LG Connect 4G (VoLTE) 1322 10.6 356 2.9 258.6 LG Spirit 4G (VoLTE) 853 11.7 232 3.2 574.5 TABLE 5- VOLTE VOICE CALL SUMMARY RESULTS 7

FIGURE 4 - CURRENT DRAIN MEASUREMENTS FOR VOLTE CALLS Device Under Test Stationary Locations Test Cycle Power Consumption Drain (ma) Session Duration (Seconds) (ma) Power Estimated Battery Life (Minutes) Cycle 1 1323 356 567 Cycle 2 1322 355 564 Location 1 Cycle 3 1320 355 535 LG Connect 4G (VoLTE) Cycle 4 1320 355 531 Cycle 5 1330 358 552 Cycle 1 1333 359 580 Cycle 2 1335 360 600 356 1322 2.9 258.6 Location 2 Cycle 3 1329 359 559 Cycle 4 1301 351 581 Cycle 5 1308 353 571 Cycle 1 836 227 602 Cycle 2 856 231 605 Location 1 Cycle 3 837 227 602 Cycle 4 848 230 616 LG Spirit 4G (VoLTE) Cycle 5 873 237 629 Cycle 1 862 234 623 232 853 3.2 574.5 Cycle 2 863 234 597 Location 2 Cycle 3 857 233 617 Cycle 4 855 232 591 Cycle 5 846 230 582 TABLE 6 - MEASUREMENTS FOR VOLTE CALLS 8

4.3. VOICE OVER IP (VOIP) CALLS USING SKYPE ON LTE When placing voice calls using Microsoft Skype s over-the-top application over the LTE network, the average current drain of the first generation device, LG Connect 4G, across all samples was measured at 385 ma. The average current drain across all samples for the second implementation of the device, the LG Spirit 4G, was measured at 258 ma. This represents a 33% improvement in current drain on the LG Spirit 4G over the LG Connect 4G for VoIP calls using Skype on the LTE network. As noted in the device profile section of this report, the most recently released LG Spirit 4G also includes 2150 mah battery which is a 38% improvement in battery capacity over the LG Connect 4G. As a result of the combination of the improvements in current drain and the additional battery capacity, there is approximately a 125% improvement in overall battery life for calls made using the Skype application on the LG Spirit 4G compared to the LG Connect 4G. Sampling Information LG Connect 4G LG Spirit 4G Average Time Per Call Cycle 578 Seconds 561 Seconds Number of Call Cycles 10 Cycles 10 Cycles Total Number of Seconds Sampled 5784 Seconds 5609 Seconds Instantaneous Power Sampling Rate 5000 Samples/Second 5000 Samples/Second Total Number of Instantaneous Measurements 28,920,000 Samples 30,045,000 Samples FIGURE 5 SUMMARY RESULTS FOR SKYPE CALLS OVER LTE 9

Device Under Test (Voice Service Type) LG Connect 4G (Skype) LG Spirit 4G (Skype) Power Consumption Power Drain (ma) Estimated Battery Life (Minutes) 1423 19.1 385 5.4 240.2 953 31.3 258 8.5 514.6 TABLE 7 - MEASUREMENTS FOR SKYPE VOICE CALLS OVER LTE FIGURE 6 - CURRENT DRAIN MEASUREMENTS FOR SKYPE CALLS OVER LTE Device Under Test LG Connect 4G (VoLTE) Stationary Locations Location 1 Location 2 Location 1 Test Cycle Power Consumption Drain (ma) Session Duration (Seconds) Cycle 1 1397 378 574 Cycle 2 1414 382 548 Cycle 3 1414 382 555 Cycle 4 1412 382 587 Cycle 5 1403 380 596 Cycle 1 1455 394 586 Cycle 2 1444 391 587 Cycle 3 1439 390 587 Cycle 4 1435 388 577 Cycle 5 1418 384 587 Cycle 1 959 260 542 Cycle 2 931 252 551 Cycle 3 955 258 574 (ma) Power Estimated Battery Life (Minutes) 385 1423 5.4 240.2 258 953 8.5 514.6 10

LG Spirit 4G (VoLTE) Location 2 Cycle 4 953 258 534 Cycle 5 952 258 543 Cycle 1 947 256 562 Cycle 2 933 252 553 Cycle 3 927 251 603 Cycle 4 935 253 547 Cycle 5 1036 280 600 TABLE 8 - MEASUREMENTS FOR SKYPE CALLS OVER LTE 4.4. SIMULTANEOUS VOICE & DATA CALLS When initiating a simultaneous voice and data session using the CDMA for voice and LTE for data on the LG Spirit 4G, the average current drain across all samples was measured at 548 ma. When initiating a simultaneous voice and data session using the VoLTE for voice and LTE for data on the LG Spirit 4G, the average current drain across all samples was measured at 488 ma. This represents a 11% improvement in current drain on the LG Spirit 4G when simultaneous voice and data calls are made using the VoLTE/LTE combination compared to using CDMA/LTE combination for voice and data on the same device. Overall this translates to approximately a 30-minute advantage for VoLTE/LTE multi-service sessions over CDMA/LTE. Device Under Test (Voice Service Type) Power Consumption Power Drain (ma) Estimated Battery Life (Minutes) LG Spirit 4G (CDMA/LTE) 2024 49.4 548 13.6 242.2 LG Spirit 4G (VoLTE/LTE) 1803 70.0 488 19.0 271.9 TABLE 9 - MEASUREMENTS FOR SIMULTANEOUS VOICE AND DATA CALLS FIGURE 7 - MEASUREMENTS FOR SIMULTANEOUS VOICE AND DATA CALLS CDMA/LTE VS. VOLTE/LTE 11

Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Average Drain (ma) Comparison of Battery Life Performance of VoLTE Capable Devices 700 Drain Measurements Simultaneous Voice & Data Call LG Spirit 4G - CDMA/LTE vs. VoLTE/LTE 600 500 400 300 200 100 0 Location 1 Location 2 Location 1 Location 2 LG Spirit 4G Simultaneous Voice & Data (CDMA/LTE) LG Spirit 4G Simultaneous Voice & Data (VoLTE/LTE) FIGURE 8 - MEASUREMENTS FOR SIMULTANEOUS VOICE AND DATA CALLS CDMA/LTE VS. VOLTE/LTE Device Under Test Stationary Locations Test Cycle Power Consumption Drain (ma) Session Duration (Seconds) (ma) Power Estimated Battery Life (Minutes) Cycle 1 2157 585 207 LG Spirit 4G Simultaneous Voice & Data (CDMA/LTE) Location 1 Location 2 Cycle 2 1974 534 209 Cycle 3 2027 549 208 Cycle 4 2007 544 211 Cycle 5 2006 543 205 Cycle 1 2014 546 211 Cycle 2 1992 540 213 Cycle 3 2020 547 208 Cycle 4 2020 547 207 Cycle 5 2021 548 206 548 2024 13.6 242.2 12

LG Spirit 4G Simultaneous Voice & Data (VoLTE/LTE) Location 1 Location 2 Cycle 1 1894 513 203 Cycle 2 1782 482 206 Cycle 3 1786 483 208 Cycle 4 1782 482 207 Cycle 5 1774 480 208 Cycle 1 1962 531 207 Cycle 2 1783 483 207 Cycle 3 1767 478 208 Cycle 4 1774 480 210 Cycle 5 1726 467 206 488 1803 19.0 271.9 TABLE 10 - MEASUREMENTS FOR SIMULTANEOUS VOICE AND DATA CALLS CDMA/LTE VS. VOLTE/LTE 5. CONCLUSION The results of the study demonstrate that the new LG Spirit 4G equipped with a single chipset architecture drains as much as 35% less current for VoLTE calls compared to VoLTE calls on the LG Connect 4G which employs previous generation dual chipset architecture, separating out the baseband processors for LTE and CDMA. The LG Spirit 4G also improves current drain for CDMA calls by 18% compared to the LG Connect 4G. Since the LG Spirit 4G also offers a larger battery (2150 mah) with 38% more capacity compared to the LG Connect 4G (1540 mah), the combination of improved current drain and increased battery capacity translates to an overall battery life improvement of 122% for VoLTE calls and 75% for CDMA calls on the LG Spirit 4G when compared to the LG Connect 4G. Calls made over the LTE network using Skype s over-the-top VoIP (Voice over IP) mobile application also experienced an improvement of approximately one-third less current drain on the LG Spirit 4G compared to the LG Connect 4G. Average current drain for simultaneous voice and data calls using the LG Spirit 4G where voice calls were made on the VoLTE network and data concurrently on the LTE network were approximately 11% below the same test performed using CDMA for voice and LTE for data. Although with an average current drain of 232 ma for VoLTE calls, the LG Spirit 4G drains 54% more current than CDMA calls on the same device, and 25% more current than CDMA calls on the first generation LG Connect 4G. The 35% and 18% reduction in current drain for VoLTE and CDMA calls respectively from the first generation to the second is an indication that improvements in power efficiency can be expected in subsequent generations of device platforms. 13