13 Fundamentals of Heat Dissipation in 3D IC Packaging …
379
(a)
(b)
Fig. 13.5 (a) Side view of proposed 3D wireless NoC architecture with interlayer cooling layer.
(b) Top view of one active layer
between layers that are not separated by a cooling layer, all the switches are equipped
with TSV based links to switches vertically above or below itself (Fig. 13.5).
Communication channels across the cooling layer are realized through wireless
links. For this purpose, each layer is logically divided into subnetworks or subnets,
such that a particular switch in each subnet is equipped with a wireless interface (WI).
The WIs are deployed in a switch at the center of the subnets to avoid long multi-hop
paths from all cores in its subnet, assuming any core can transmit inter-subnet data
at some point during the operation of the system. This WI deployment strategy has
been shown to provide the minimum average distance (MAD) between all switches
in an intra-chip NoC in [41]. All cores that need to send data across a cooling layer
access the wireless channel through the WI in its subnet. The WIs are connected in
an all-to-all fashion using the shared wireless band as discussed in Sect. 3.3. The
data is transferred to the WI in the subnet of the destination core from where it is
routed to the final destination. In order to improve performance, data transfer within
the same layer or in adjacent layers not separated by a cooling layer can also use the
WIs depending on the adopted routing policy as discussed in Sect. 3.4. In this way,
a hybrid hierarchical 3D wireless, wireline and TSV based NoC architecture (3DHiWiNoC) is formed. Figure 13.1b shows the top view of one active layer (vertical
TSVs are not shown).
The cores in the 3D multicore system will be interconnected using a NoC fabric
through switches and links. In our proposed architecture, each core is connected
to a NoC switch. Switches within a single layer are connected in a mesh topology
with conventional copper wire based NoC links. To enable interlayer communication
between layers that are not separated by a cooling layer, all the switches are equipped
with TSV based links to switches vertically above or below itself.
379
(a)
(b)
Fig. 13.5 (a) Side view of proposed 3D wireless NoC architecture with interlayer cooling layer.
(b) Top view of one active layer
between layers that are not separated by a cooling layer, all the switches are equipped
with TSV based links to switches vertically above or below itself (Fig. 13.5).
Communication channels across the cooling layer are realized through wireless
links. For this purpose, each layer is logically divided into subnetworks or subnets,
such that a particular switch in each subnet is equipped with a wireless interface (WI).
The WIs are deployed in a switch at the center of the subnets to avoid long multi-hop
paths from all cores in its subnet, assuming any core can transmit inter-subnet data
at some point during the operation of the system. This WI deployment strategy has
been shown to provide the minimum average distance (MAD) between all switches
in an intra-chip NoC in [41]. All cores that need to send data across a cooling layer
access the wireless channel through the WI in its subnet. The WIs are connected in
an all-to-all fashion using the shared wireless band as discussed in Sect. 3.3. The
data is transferred to the WI in the subnet of the destination core from where it is
routed to the final destination. In order to improve performance, data transfer within
the same layer or in adjacent layers not separated by a cooling layer can also use the
WIs depending on the adopted routing policy as discussed in Sect. 3.4. In this way,
a hybrid hierarchical 3D wireless, wireline and TSV based NoC architecture (3DHiWiNoC) is formed. Figure 13.1b shows the top view of one active layer (vertical
TSVs are not shown).
The cores in the 3D multicore system will be interconnected using a NoC fabric
through switches and links. In our proposed architecture, each core is connected
to a NoC switch. Switches within a single layer are connected in a mesh topology
with conventional copper wire based NoC links. To enable interlayer communication
between layers that are not separated by a cooling layer, all the switches are equipped
with TSV based links to switches vertically above or below itself.