The USB Implementers Forum normally shows up at the Consumer Electronics show to hightlight the latest products from members. There is plenty of new USB 3.0 technology to go around but this time around they had a new announcement that affects everyone. They plan on doubling the throughput of the SuperSpeed USB 3.0 that currently runs at 5 Gbits/s.
10 Gbit/s is a nice round number and plenty of throughput. The addendum to the USB 3.0 standard will define the new protocols and specifications. Product using the new standard will likely arrive in about a year so this is a forward looking announcement.
The new standard will be compatible with existing USB 3.0 stacks and device class protocols. It will be compatible with existing cables and connectors. Cables under 1m should be able to handle the new speeds without increasing the cost of the cable. A new certification will be required to handle the higher speeds.
USB 3.0 operating at 5 Gbit/s will use the existing signalling methodology. The 10 Gbit/s protocol changes the signalling methodology. About 20% of the performance improvement is garnered using a new encoding scheme. PCI Express used the same approach to up its bandwidth.
Most high speed serial protocols use an encoding like 8b/10b that sends 8 bits of data in a 10 bit sequence. The reason is to guarantee a sufficient number of transitions within the block so the receiver can remain in sync. The longer the sequence, the lower the overhead.
Faster clock rates will cost more in terms of power but overall the amount of power per bit goes down. This is because the data will take less time to transfer. Overall, the power requirements for 10 Gbit/s USB 3.0 will be lower than for 5 Gbit/s USB 3.0.
On another note, the SuperSpeed USB Inter-Chip (SSIC) specification is out. This chip-to-chip connectivity utilizes MIPI's M-PHY support. MIPI M-PHY is common on smartphones where low power, high speed and low pin count is key. USB is just one aspect of the MIPI support.
USB 3.0 use is dominated by storage applications right now but that has been changing. Display support is another area where faster throughput is important.