Advanced XGP (XGP standard version 3, revision 1)
XGP Forum developed XGP version 3, revision 1 (XGP3.1) in Feburary 2014. XGP3.1 is more evolutional system which support some advanced technology including Carrier Aggregation and XGP unique optional features.
(1) More advanced features
XGP3 describes the new features based on 3GPP Release 10 and Release 11.
- Carrier Aggregation Enhancement
- Coordinated Multi-Point (CoMP) transmission and reception
- Enhanced inter-cell interference Coordination (eICIC / HetNet)
- Enhanced MIMO (Higher Order MIMO and SU-MIMO for uplink)
- Enhanced UL transmission (Non-contiguous SC-FDMA)
(2) XGP unique optional features
XGP Forum specifies XGP unique optional features for Global Mode. As one of XGP unique optional features, XGP3 describes Public Warning System (PWS) which is used by Earthquake and Tsunami Warning System (ETWS). Considering the total operation balance, this feature may or may not be introduced in actual Global mode network.
Carrier Aggregation (CA) enables to aggregate two or more Component Carriers (CC) in order to support wider transmission bandwidths up to 100MHz. Note that individual maximum bandwidth of CC is 20MHz.
CA supports for both contiguous and non-contiguous CCs. That is, CA will allow a more flexible use of diverse spectrum allocations available in an operator network.
There are two aggregation type by CCs; one is to aggregate both directions, the other is to aggregate only downlink. Note that the former type needs further study by 3GPP. As for the latter type, there are two aggregation type by numbers of eNB; one is to aggregate downlinks from multiple eNBs, the other is to aggregate downlinks from one eNB.
Table: Example of downlink speed supporting Carrier Aggregation
(Assumption: Ratio of uplink to downlink is 1:3)