Haibin Zhang, Michal Golinski [email protected] , TNO [email protected] , TNO SUNSEED project is partially funded by EC FP7 programme under grant agreement #619437. Problem Description Determine the maximum density of SM and WAMS nodes supportable in an LTE network, for: a) Desired amount of (uplink) data transmitted by the SM or WAMS node; b) A certain ratio of the SM number over the WAMS number; c) Different spectrum bands, and propagation environment (urban, sub‐ urban, rural). d) Different LTE cell densities, represented by the cell radius of LTE sites. Analysis Approach The assumption is that the uplink is the capacity bottleneck for the Smart Grid application. For each considered spectrum band (1800MHz or 800MHz), each of considered environment (urban, sub‐urban or rural), and each of selected cell radius, the following steps are taken: • Simulating randomly placed terminals within the coverage area of an LTE cell (hexagonal layout) and calculating their achieved uplink SINR for a given interference level and allocated number of PRBs. • From the uplink SINR the applied modulation and coding schemes (MCSs) in the uplink is determined for given block error rate (i.e. re‐ transmissions are considered). • For each MCS, calculate the number of transport blocks needed to deliver the desired amount of traffic from the SM and WAMS nodes. The transport block size is standardized, and depends on the MCS and the number of PRBs assigned per terminal. • From the above, one may derive the average number of transport blocks required to deliver the amount of traffic averaged over all nodes. • The capacity of an LTE cell in terms of average number of nodes is derived by dividing the total number of available transport blocks by the average number of transport blocks per node. The average density of SG nodes in the urban environment for 800MHz (left) and 1800 MHz (right), for the different ratio of WANS over SM nodes (1/3 or 1/6), and the different traffic demand of WAMS (517.12 or 51.71 bytes/s), the traffic demand of SMs is 0.947 byte/s. LTE bandwidth is 10MHz. Conclusions • By utilizing the full 10 MHz LTE carrier at 800MHz or 1800 MHz band the amount of SM and WAMS nodes can be up to in the order of few tens to hundred thousand nodes based on the selected cell range, which in practical deployments is not seen as a limiting factor. • At the lower traffic demand of WAMS (51.71 bytes/s), the ratio of WAMS nodes over SMs has limited impact to the overall capacity. On the other hand, at the higher traffic demand of WAMS (517.12 bytes/s), the impact is much more obvious. • This analysis did not consider the communication latency requirements, signaling and scheduling overhead, sharing the resources with non SG traffic, uniform SG traffic distribution during the day, etc. Thus, the obtained results can be seen as performance upper bound of LTE. • As next step, we will consider these practical limits to improve the capacity analysis.

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Page 1: 03 SUNSEED Workshop LTE Capacity Analysis TNO …sunseed-fp7.eu/wp-content/uploads/2015/04/03_SUNSEED-Workshop … · Title: Microsoft PowerPoint - 03_SUNSEED Workshop LTE Capacity

Haibin Zhang, Michal [email protected] , [email protected] , TNO

SUNSEED project is partially funded by EC FP7 programme under grant agreement #619437.

Problem DescriptionDetermine the maximum density of SM and WAMS nodes supportable in anLTE network, for:a) Desired amount of (uplink) data transmitted by the SM or WAMS node;b) A certain ratio of the SM number over the WAMS number;c) Different spectrum bands, and propagation environment (urban, sub‐

urban, rural).d) Different LTE cell densities, represented by the cell radius of LTE sites.

Analysis ApproachThe assumption is that the uplink is the capacity bottleneck for the Smart Grid application. For each considered spectrum band (1800MHz or800MHz), each of considered environment (urban, sub‐urban or rural), and each of selected cell radius, the following steps are taken:• Simulating randomly placed terminals within the coverage area of an LTE cell (hexagonal layout) and calculating their achieved uplink SINR for

a given interference level and allocated number of PRBs.• From the uplink SINR the applied modulation and coding schemes (MCSs) in the uplink is determined for given block error rate (i.e. re‐

transmissions are considered).• For each MCS, calculate the number of transport blocks needed to deliver the desired amount of traffic from the SM and WAMS nodes. The

transport block size is standardized, and depends on the MCS and the number of PRBs assigned per terminal.• From the above, one may derive the average number of transport blocks required to deliver the amount of traffic averaged over all nodes.• The capacity of an LTE cell in terms of average number of nodes is derived by dividing the total number of available transport blocks by the

average number of transport blocks per node.

The average density of SG nodes in the urban environment for 800MHz (left) and 1800 MHz (right), for the different ratio of WANS over SM nodes (1/3 or 1/6), and the different traffic demand of WAMS (517.12 or 51.71 bytes/s), the traffic demand of SMs is 0.947 byte/s. LTE bandwidth is 10MHz.

Conclusions• By utilizing the full 10 MHz LTE carrier at 800MHz or 1800 MHz band the amount of SM and WAMS nodes can be up to in the order of few

tens to hundred thousand nodes based on the selected cell range, which in practical deployments is not seen as a limiting factor. • At the lower traffic demand of WAMS (51.71 bytes/s), the ratio of WAMS nodes over SMs has limited impact to the overall capacity. On the

other hand, at the higher traffic demand of WAMS (517.12 bytes/s), the impact is much more obvious.• This analysis did not consider the communication latency requirements, signaling and scheduling overhead, sharing the resources with non

SG traffic, uniform SG traffic distribution during the day, etc. Thus, the obtained results can be seen as performance upper bound of LTE. • As next step, we will consider these practical limits to improve the capacity analysis.