|Data Communication and Data Management Laboratory @ University of Texas at Dallas|
Mobile Computing and Wireless Networking
Virtual Backbone Assisted Routing for Ad Hoc Networks
Most existing routing protocols suffer from the "broadcast storm problem". By maintaining a virtual backbone over the physical layer, and running routing protocols over the virtual backbone, we can greatly alleviate this problem.
optimization problem: Minimum Connected Dominating Set (MCDS)
Resource-Aware Routing for Wireless Networks
Resource constraint is a serious problem in wireless network design, especially for all-wireless networks. A host with almost depleted power, or a buffer overflow, etc., tends to decrease network capacity. Thus, putting the routing burden on hosts with more available resources is very important.
Related optimization problem: Optimal Resource Allocation
QoS Related Issues
link is very unreliable when compared to its wired counterpart. Providing QoS
routing for multimedia traffic (video/audio) is very challenging. The limited
bandwidth of wireless networks makes this problem harder.
optimization problem: Channel Allocation and Assignment
Power-Aware Routing in Ad Hoc Wireless Networks
1. Why Power Control?
- Most mobile hosts today operate using batteries
- A significant fraction of the wireless node power is consumed by the wireless network interface cards that are responsible for transmitting packets
- Higher transmission power of one host incurs higher interference to other hosts
2. Benefits from Power Control
- Prolonged battery life and system (network) life
- Admission control, link QoS maintenance, resource allocation, mobility and channel impairment adaptation
- Interference mitigation & network capacity increase
- Efficient handling of mobility (handoffs, etc.) Strategies in each network layer Physical Layer
3. Strategies in each network layer
- Minimum power transmission to maintain links
- Problem: compute minimum energy consumed per host to maintain k-connected graph
- Power controlled multiple access, effective retransmission request scheme
Layer - maximize network life time
- Power consumed by each node must be evenly distributed
- Total transmitted power for each connection must be minimized
- Problem: How to solve the dilemma?
- Modify TCP protocol parameters
QoS and Resource Management
- Applications with real-time constraints: multimedia & C2
- Node mobility and variable connection reliability
- Consider probabilistic resource availability
- Adaptive resource management system
- Define probabilistic resource/service model
- Optimize service distribution and resource allocation