The LTE/SAE Trial Initiative (LSTI), a unique global collaboration between vendors and operators, has successfully completed and reached the objectives of the TD-LTE (LTE TDD) Proof of Concept (PoC) Milestone 3 and Milestone 4 test phases: Demonstration that the basic LTE/SAE functionality and performance are achievable with pre-standards prototype equipment. Time-Division Duplex (TDD) is the application of time-division multiplexing that separates transmit and receive signals.
For the TD-LTE Proof of Concept M3/M4 testing, LSTI had identified a core set of proof points aligned with the 3GPP (Third Generation Partnership Project) and NGMN (Next Generation Mobile Networks Alliance) requirements for LTE/SAE. The work of M3/M4 TD-LTE phases consisted of analysis of the 3GPP and NGMN requirements, test methods and configurations, delivery of supporting results from the vendors, and analysis and consolidation of these results by LSTI PoC Work Group. Over 90 measurement campaigns from seven vendors have been consolidated to determine the ability of LTE to bring an enhanced user experience to consumers, and to help operators understand how the technology will function in realistic scenarios.
Data Rate Results
• The industry’s peak spectral efficiency target of 5 bps/Hz downlink and 2.5 bps/Hz uplink can be achieved in a live air test.
• MIMO technology working in realistic conditions, with rates of over 40 Mbps (spectral efficiency: 7.3 bps/Hz) measured in the field with a 2x2 antenna configuration.
• End user rates will vary widely depending on radio conditions and network loading. The minimum offered speed at ‘cell edge’ during busy hour is expected to be around 0.06 bps/Hz/User spectral efficiency (with ten active users per cell). This aligns with the 3GPP design target of 2-3x higher than HSDPA.
• LTE/SAE can provide Guaranteed Bit Rates in order to support real time services such as IPTV.
• Initial results demonstrate that TD-LTE can support speeds up to 350km/h, and also 500km/h has been demonstrated in good radio conditions.
• Measured connection setup times are under the requirement of 100 milliseconds.
• One way over-the-air packets transmit times of under 5ms have been achieved with TD-LTE system.
• Round trip response times experienced by end users ‘pinging’ an internet server meet the 3GPP and industry targets.
• Tests in ideal lab conditions have demonstrated that TD-LTE is capable of supporting VoIP with minimal latency, jitter and packet loss.
• Mobility testing in the field has shown that data flow interruption times during handovers are meeting the NGMN ‘real time service’ requirement even in high definition video conferencing usage scenarios.
In addition, a series of Operator open day visits to vendors’ facilities were arranged in order for the operators to witness and observe the actual test conditions, to speed up the discussions in the common meetings and to gain better confidence and support from the operator community.
With these milestones, the Proof of Concept tests, the first testing phase of the LSTI alliance; has been completed for both FDD and TDD. With the PoC complete, LSTI can move to other phases of working including, IODT, IOT, and FCT in a timely manner.
”LSTI is focused on accelerating the development of 3GPP LTE/SAE technology for both networks and devices,” said Hou Fang of Huawei and Chairman of TDD Proof of Concept Group, LSTI. “Having stable 3GPP LTE/SAE specifications and accelerating industry-wide interoperability testing within LSTI across the LTE/SAE networks and devices will simplify the worldwide adoption of LTE/SAE technology regardless of who designed, built, or operates these networks and devices. These LSTI PoC results form the basis for the ongoing/upcoming LSTI phases such as the Interoperability Development Tests, the Interoperability Tests and the Friendly Customer Trials, beta tests which will be performed under conditions similar to those in the market.”