People
Prof. Heather Zheng
Ashwin Sampath (wireless routing)

In the News A recent presentation Prof. Zheng gave at Dyspan 2005 general session on rule based spectrum management, followed by a panel discussion on the paper. The paper can be found here.

Prof. Heather Zheng selected as TR35: 2005 MIT Technology Review Top 35 Innovators under the age of 35 (UCSB & UMCP news)

Prof. Zheng's talk at UC Berkeley Networking Seminar on Managing Open Spectrum Systems , Oct. 10, 05; also at Bell-Labs, NJ, Sept. 05.

2 papers accepted by Dyspan05

CS290F in Winter 2006 on intelligent wireless systems

Links
FAQ for prospective students

Prof. Ben Zhao &
UCSB Current Lab

Conferences
Dyspan05 11/8-11/11
mobihoc06 CFP 12/2

Contact
Prof. Haitao (Heather) Zheng
Engineering I, 2159
Computer Science, UCSB
Santa Barbara, California 93106-5110
Phone: +1 (805) 893-3560
Fax: +1 (805) 893-8553

Intelligent Networking
The fundamental concept behind Intelligent Networking is to push Human brain-power into end-devices. Human are intelligent and adaptive. We sense neighborhood environment, adapt to dynamics and variations, and learn from past experiences to change future behavior. This is so called cognitive cycle.

Our approach is to apply the concept of cognitive to network elements that allows networks to manage themselves in a self-aware and adapative manner. Areas to be addressed include self-organizing networks, adaptive routing and MAC protocol design, network resource management, topology discovery/control, security as well as network infrastructures.

• Application of reasoning and learning to facilitate improved efficiency, performance, fault-tolerance, security and other funcationality of networks.
• Introduction of adaptive self-organization to provide fault-tolerant, reliable operations in resource constrained networks.
• Introduction of device collaboration to optimize network operation in a distributed way.
• Exploiting cognitive radio enabled open spectrum systems to enhance connectivity, improve capacity and reduce cost.
  
  Associated Projects:
  
• Routing and MAC
1. DART (Adaptive Routing) - reliable and resource efficient routing protocols
2. SMART (Spectrum Aware Routing) - exploiting interactions between spectrum management and routing
3. TESLA (Efficient and Fair Spectrum Access) - distributed spectrum allocation algorithms
• Security and defense
1. Secure open spectrum systems
2. Defense against jamming attacks

Fundations
Our projects are built on top of prior research experiences on cognitive radio and open spectrum systems. Prior work on MAC layer issues such as dynamic spectrum allocation and distributed coordination provides initial building blocks towards the implementation and deployment of a fully operational cognitive networks. We are currently addressing networking and MAC level issues, which also extend the concept of cognitive radio into the general aspects of system and networking.

Previous work focuses on the design of decentralized infrastructure for Open Spectrum system, where devices interact to efficiently utilize spectrum, while optimizing for traditional goals such as fairness and maximizing utilization. The project combined expertise from multiple areas: distributed artificial intelligence, game theory and wireless communications & networking together. This work has produced efficient distributed algorithms for spectrum management and coordination, backed up by strong theoretical results.

Associated Projects (projects that I initiated and worked on at Microsoft Research Asia (2004-2005))

• Nautilus: Collaboration and Fairness in Spectrum Access
  We show that collaboration among devices, together with appropriate regulations, provides a strong base for fair and efficient spectrum usage.  When direct collaboration is not possible (due to signaling compatibility, radio design, protocol constraints, etc.),  rule based spectrum management where each device follows a network-enforced rule set would provide similar performance as in collaboration based approaches. These results make Open Spectrum communication efficient and cost-effective, paving the way to large scale deployment. (collaborations with Lili Cao (shanghai Jiaotong), Chunyi Peng(Tsinghua))
  
  
• HDMAC: Distributed Coordination in Dynamic Spectrum Environments
  Collaboration among devices requires efficient coordination. In addition, traffic coordination between devices are required for reliable communications. That is, each transmitter and receiver pair needs to synchronize their spectrum usage. Coordination requires a signaling path among devices for information exchange. Unlike fixed spectrum systems, spectrum heterogeneity in open spectrum systems prevents the use of a common coordination channel.  Instead, secondary devices must select them dynamically, while minimizing the total number of coordination channels in the network and maintaining connectivity.  We propose a distributed, scalable and efficient coordination framework where devices dynamically select their coordination channel based on local conditions. Without relying on the existence of a pre-assigned common control channel, HD-MAC carries potential to provide robust operation under network dynamics. While this approach can be implemented by upgrading the legacy protocol stack without modifying the MAC protocol,  modifications to the MAC protocol that address spectrum heterogeneity and significantly improve system performance. (collaborations with Jun Zhao (MSRA), Guanghua Yang (HKU) )
  


• Im-a-Relay: Interference Managment for Cooperative Diversity
  This work focused on the effectiveness of cooperative diversity in interference limited ad hoc networks. Cooperative relay exploits spatial diversity available through cooperative terminal's relaying signals for one another. With such forms of diversity comes the penalty of extra interference to other neighboring terminals. We demonstrate that careless usage of cooperative relay raises service blocking probability, and there is a tradeoff between spatial diversity and service disturbance through interference. We propose to incorporate the process of relay selection with that of channel access to achieve a balance of such tradeoff. (collaborations with Yan Zhu (Northwestern), Cong Shen (UCLA), X. Wang (Columbia))

A Short Introduction to Cognitive Radio and Open Spectrum
Wireless devices are becoming ubiquitous, placing increasing stress on the fixed radio spectrum available to all access technologies. This leads to spectrum scarcity problem. To eliminate interference between different wireless technologies, traditional (and current) policies allocate a fixed spectrum slice to each technology, i.e. command and control. This static assignment prevents devices from efficiently utilizing allocated spectrum, resulting in spectrum holes (no targeted devices in local area) and very poor utilization (6-10%) in other geographic areas (source DARPA). Given that the current spectrum licensing policy facing near-future threat of spectrum scarcity and the increasing crowd in unlicensed spectrum band, efficient spectrum management is necessary and critical to future development of system and networking.

Enabled by software defined radio (SDR) technology, Open Spectrum allows unlicensed (secondary) users to share spectrum with legacy (primary) spectrum users, thereby "creating" new capacity and commercial value from existing spectrum ranges. Based on agreements and constraints imposed by primary users, secondary users opportunistically utilize unused licensed spectrum on a non-interfering or leasing basis. Open Spectrum systems have a high potential for impact, and can enable large segments of the world population to be connected efficiently and cost effectively using a variety of devices, while making world-wide deployment easy for service providers. It is envisioned to have an impact on wireless system and networking like the way that Internet and packet switching have reshaped the world.

Open spectrum requires a new line of cognitive radios. Cognitive refers to a device's ability to sense surrounding environment conditions and adapt its behavior accordingly. This  process is often referred to as cognitive cycle: (sense - characterize - learn - adapt). The advent of cognitive radio clearly portends a potential revolution in wireless networking. It makes every aspect of wireless transmission and reception programmable. Devices can intelligently select the transmission format and media access technology, while all these characteristics are software-reconfigurable. Most importantly, devices equipped with cognitive radio can constantly monitor the spectrum and discover how the spectrum is being used. By dynamically reconfiguring it to transmit in a way that does not interference with existing users, cognitive software radio allows exploitation the portion of spectrum that is allocated but unused. This creates additional capacity and revenue from existing spectrum, and addressing spectrum scarcity problem. The concept of cognitive radio has received enormous attention from both government (FCC, DARPA, NSF, ARMY, ONR) and major industrial sources.  In addition, the introduction of cognitive radio could potentially restructure the industry,  significantly increasing the role of software in devices, and the role of end-devices in system and networking.

Power up the devices

Last modified by Heather Zheng, 10/25/2005