What’s the Difference Between LTE ICIC and LTE-Advanced eICIC?

Recently, I've been looking into a couple of LTE-Advanced features and was wondering a bit what the difference is between ICIC (Inter-cell Interference Coordination) introduced for LTE in 3GPP Release 8 and eICIC introduced in 3GPP Release 10 as part of LTE-Advanced. Here's my take on it in abbreviated form, for a longer description I found a good resource here.

3GPP Release 8 LTE ICIC: This is an optional method to decrease interference between neighboring macro base stations. This is done by lowering the power of a part of the subchannels in the frequency domain which then can only be received close to the base station. These subchannels do not interfere with the same subchannels used in neighboring cells and thus, data can be sent faster on those subchannels to mobile devices close to the cell.

3GPP Release 10 LTE-Advanced eICIC: This is part of the heterogeneous network (HetNet) approach, where macro cells are complemented with pico cells inside their coverage area (hotspots in shopping centers, at airports, etc.). While the macro cells emit long range high power signals, the pico cells only emit a low power signal over short distances. To mitigate interference between a macro cell and several pico cells in its coverage area, eICIC coordinates the blanking of subframes in the time domain in the macro cell. In other words, there is no interference in those subframes from the macro cell so data transmissions can be much faster. When several pico cells are used in the coverage area of a single macro cell overall system capacity is increased as each pico cells can use the empty subframes without interference from the other pico cells. The downside is of course that the macro cell capacity is diminished as it can't use all subframes. Therefore, methods have to be put in place to quickly increase or decrease the number of subframes that are assigned for exclusive use of in pico areas when traffic patterns change.

In other words, ICIC is a macro cell interference mitigation scheme, while eICIC has been designed as part of HetNet to reduce interference between the macro and pico layer of a network (once pico cells are rolled out to increase coverage and system capacity).