Democratizing Cellular Access with AnyCell

https://www.youtube.com/watch?v=VSu-osNE26w&t=76s

Presentation

Outline

• Why a new cellular architecture?

• Cellbricks: overall approach

• Prototype implementation

Growing the tent in cellular

• Today's cellular ecosystem is dominated by a small number of mobile network operators (MNOs)

• Our goal: lower the barrier to entry for new entrants

• Key: ensure MNOs with a small/mid-scale footprint can play

  • City government, university campus --> equal participant

• This is difficult with today's architecture!

Today's architecture relies heavily on trust and in-network coordination

• Authentication / accounting built on trust between the user and its MNO

• Seamless mobility built on coordination between towers (handovers)

• Broad coverage built on coordination / trust between MNOs (roaming)

Pre-establishing trust doesn't scale!

Seamless mobility via in-network coordination does not scale

The same problems exist with MVNOs

• User signs up for MVNOs

• MVNO still needs to go out and have trust agreements with all MNOs

Cellbricks: a new cellular architecture

• Goal: enable users to consume access on-demand from any available infrastructure operator without requiring pre-established trust or in-network coordination

• Potential benefits:

  • Lower barrier to entry for new operators

  • More efficient use of infrastructure

  • Simpler infrastructure

• Two main challenges

  • Secure attachment and billing (without mutual trust)

  • Seamless mobility (without in-network coordination)

Secure attachment

• Today: share keys, cellbricks: public keys

  • How any online transaction works (use exactly the same authentication)

  • 3-way authentication

  • Evidence: serving a valid user that belongs to a particular broker, and that the MMO is actually the one the user wanted to connect to

• Broker to pay the MNO accordingly

• Broker and MNO: reputation system

Seamless mobility

• Today, handovers require cooperation between towers

  • Allows a UE's IP address to stay unchanged (TCP connection stays unchanged, application sessions persist)

• In CellBricks, handovers may involve different MNOs

  • Different to preserve a UE's IP address across admin boundaries

• Solution: leverage modern transport protocols (MPTCP, QUIC)

  • L4 connection is maintained even if the UE's IP address changes

• Moving mobility support out of the network and into the transport layer

Prototype

• USRPs

  • Provide ratio connectivity (no changes to RAM)

• srsLTE

  • UE and eNodeB

• Magma

  • AGW: extended to support secure attachment (3-way secure attachment)

  • Orc8r: added a Brokerd service

• Performance

  • End-to-end latency of attachment protocol

  • UE, eNodeB, AGW in local machines

  • Vary locations for SubscriberDB (S6a) and brokered

Host-driven mobility is a promising direction to explore further

Conclusion

• Technical pieces for a radically different cellular ecosystem

  • Public key based 3-way authentication

  • Secure counters in device hardware

  • Promote the adoption of MPTCP, QUIC

• Status

  • Early prototype on Facebook's Magma

  • Real-world measurements of overheads (MPTCP, handovers)