InterDigital’s Insight into Permissioned Distributed Ledger (PDL)
This January, InterDigital’s Chonggang Wang, together with a team of expert ETSI members, led the effort to develop a white paper introducing the groundbreaking concept of Permissioned Distributed Ledger (PDL).
As one of the new topics explored in InterDigital’s Future Wireless lab, Distributed Ledger Technology (DLT) has emerged as a hyper-disruptive technology because of its ability to securely store and verify data as digital records distributed across multiple sites, without the need for a central administrator.
There are two types of distributed ledger systems split by access: Permissionless and Permissioned Distributed Ledgers (PDLs). Unlike permissionless systems, PDLs depend on their participating community to agree upon access control policies to maintain privacy and establish protocols to achieve higher transaction speeds and energy-efficiency, compared to permissionless solutions.
PDL and blockchain hold great promise for an array of emerging applications, and the Industry Specification Group (ISG) on PDL at ETSI are drafting new reference architectures to leverage PDL capabilities towards a new range of applications.
To detail the impact of this important work, InterDigital’s Chonggang Wang shares his expertise in answering the questions below.
IDCC Comms: Chonggang, you were the lead author, coordinating the ETSI white paper “Introduction of Permissioned Distributed Ledger (PDL),” alongside partners from Telefonica S.A., Kings College London, Huawei, PCCW Global, Motorola Mobility, China Unicom, ALASTRIA, and others. Can you help us understand distributed ledger technology and the impact it delivers to our system architectures?
Chonggang: I am honored to work with other DLT experts and leaders to co-develop this white paper and appreciate their great contribution. DLT is not a magic technology, but it magically integrates multiple components and techniques (e.g., cryptography, hashing/chaining, distributed ledgers, consensus protocols, and underlying peer-to-peer networks), which had been impossible and brings a combination of multiple unique features (e.g., decentralization, immutability, transparency). For example, DLT does not rely on a centralized party, but multiple distributed parties (e.g., ledgers, validators) to interact with each other and reach agreements, which makes the system more efficient, autonomous, reliable, and trustworthy. DLT is not only a decentralized technology but can be treated and leveraged as a design principle and philosophy to enable an Internet of Data/Value and result in numerous applications for future digital economy.
IDCC Comms: How might we see PDL technologies applied in the mobile industry? What use cases best display PDL’s capabilities?
Chonggang: On one hand, future wireless mobile systems will become more distributed and open as we have witnessed from today’s 5G technologies in edge computing and open radio access networks. On the other hand, such distributed and open mobile systems demand better efficiency, transparency, trustworthiness, accountability and so on. PDL technologies can definitely meet these demands, for instance, leveraging PDL to enable decentralized wireless artificial intelligence and decentralized spectrum and wireless resource sharing. As described in the white paper, “PDL can largely benefit the identification and authentication service to enable a more privacy-protected digital identification and authentication (i.e., using a digital identifier that can be self-sovereign and user-controlled) for seamless on-demand network access and service provision”. In fact, DLT has been broadly envisioned as a critical enabler to boost 6G.
IDCC Comms: As lead author of this white paper, what is the most important thing people should understand about PDL and its impact?
Chonggang: PDL reference architecture especially the PDL service layer sets the foundational framework for the entire PDL system. Other important areas include smart contracts, offline operations, distributed data management, and inter-ledger interoperability. In fact, this white paper aims to provide an introduction of the PDL system, which also includes use cases and advanced technologies. For deeper technical details, it’s highly suggested to also check out the white paper’s corresponding references and documents.
IDCC Comms: Aside from this white paper, what other work is being led at ETSI around PDL? How are you engaged?
Chonggang: ETSI ISG PDL currently has four active work items: 1) GR PDL-006 on Inter-Ledger Interoperability; 2) GS PDL-012 on PDL Reference Architecture Framework; 3) GS PDL-013 on PDL for Supporting Distributed Data Management; 4) GR PDL-014 on Non-Repudiation Techniques. I am the rapporteur for GS PDL-013. In addition, ISG PDL promotes PDL Proof of Concepts (PoCs); for example, an ongoing PoC is “Timeless in Metaverse Environment based on Edge networks (TIME)”. ISG PDL organizes plenary meetings (online so far due to the pandemic), bi-weekly conference calls and regular online drafting sessions to facilitate the delegates to have fruitful technical discussions and progress work items. ISG PDL always welcomes contributions from new and current member companies. If interested, please check out the ISG website here.
IDCC Comms: What is the potential for PDL and advanced distributed ledger technologies in the future? How soon might we see these technologies standardized for commercial use?
Chonggang: As described in the white paper, PDL can be applied to (but not limited to) many vertical domain and applications such as mobile networks, data sharing and management, and artificial intelligence, which are catalysts for the digital economy with boundless potential. In addition, advanced distributed ledger technologies like redactable ledgers and payment channel networks will make the technology more scalable and efficient with improved privacy. DLT-related standardization activities have been going on in many SDOs such as ITU-T, IEEE, ETSI and IETF. It’s hard to predict the timeline of the standardized commercial deployment of PDL systems, but many proprietary DLT solutions for commercial use have been seen in recent years. The next step might be to standardize PDL especially a PDL service layer for some application vertical domains such as the mobile industry, which will boost the large-scale standardized deployment of PDL technologies.