There's a new PCI Express standard on the way, and it's tailored specifically for mobile devices like smartphones, tablets, and ultra-thin laptops. Dubbed Mobile PCI Express, or M-PCIe, the specification is being developed by the PCI-SIG governing body in cooperation with the MIPI Alliance standards group. Both are bringing something to the table; M-PCIe uses MIPI's M-PHY physical layer technology as the conduit for PCI Express communication.
The Mobile PCI Express standard is currently being reviewed and should be available to PCI-SIG members in the spring. Few details are available, but we know M-PCIe will be introduced as an amendment to the PCI Express 3.0 specification. The goal is to provide a scalable, power-efficient interface for the next generation of mobile devices.
PCI Express 3.0 offers 8Gbps of bandwidth per lane, which isn't far off the 6Gbps maximum speed of the current M-PHY spec. It's unclear whether the mobile standard will be able to deliver the full performance of PCIe 3.0, though. At the very least, the scalable interface should be able to offer additional bandwidth via extra lanes.