Goldsmith, A. and Wicker, S. "Design Challenges for Energy-Constrained Ad Hoc Wireless Networks". IEEE Wireless Communications. Aug 2002
Goldsmith does the usual of ad hoc network papers and describes what they are and what they are useful for. It focuses on energy concerns of the devices within these networks. The paper says that a "cross-layer design" needs to be used that is a more holistic approach to conserving the energy of the device. Many components such as multiple antennas, power control and scheduling at different layers, and efficient coding all need to be a part of the design with ad hoc networks in mind.
The findings assert that the most difficult things to counter in energy consumption are topology of the environment, lack of centralized control, and limited node capability. Newer ways of design have attempted to tackle these problems and have a more full (holistic) approach to saving energy.
Thursday, April 12, 2012
Paper Reading #9: CAN mobile gaming be imrpoved?
Fritsch, T., Ritter, H. and Schiller J. "CAN mobile gaming be imrpoved?". The 5th Workshop on Network & System Support for Games 2006.
Fritsch presents a MANET peer to peer network that is compared to basic broadcasting across an entire network in order to send packets. CAN stands for Content Addressable Network. The network is addressed using a hash table that maps into a virtual space the network structure. It uses Patsy and Chord data structures for the address space in the coordinate system. The paper does not describe the implementation of the network or the data structures, but shows the comparison to simply broadcasting over a dense network.
CAN has a larger overhead of constructing a network which is to be expected, and takes up to 6 minutes to construct a network of 100 users. This being the case, there is a threshold for each test they do in terms of packet sending and node connection. At each threshold, CAN outplays a regular broadcast.
Fritsch presents a MANET peer to peer network that is compared to basic broadcasting across an entire network in order to send packets. CAN stands for Content Addressable Network. The network is addressed using a hash table that maps into a virtual space the network structure. It uses Patsy and Chord data structures for the address space in the coordinate system. The paper does not describe the implementation of the network or the data structures, but shows the comparison to simply broadcasting over a dense network.
CAN has a larger overhead of constructing a network which is to be expected, and takes up to 6 minutes to construct a network of 100 users. This being the case, there is a threshold for each test they do in terms of packet sending and node connection. At each threshold, CAN outplays a regular broadcast.
Thursday, April 5, 2012
Paper Reading #8: Blue Danger: Live action gaming over Bluetooth
L. Wang, E. De Vial and L. Tokarchuk. Blue Danger: Live action gaming over Bluetooth. Queen Mary, University of London, School of Electronic Eng. and Computer Science.
The developers created a framework for adding on to a game call Blue Danger. The purpose of the game is almost exactly like assassins. The user development is in the creation of weapons and defense systems.
Once thirty users join a group, the game would automatically start. Each person would be given a certain amount of health and as different weapons hit people through a bluetooth connection, your health would lower until you were finally dead. Your target would then be given to your assassin.
The paper does not explain any testing done, however it does hint at some based upon the reference to different types of phones and their bluetooth connection time. They say that this is a flaw in connection that needs to be addressed.
The developers created a framework for adding on to a game call Blue Danger. The purpose of the game is almost exactly like assassins. The user development is in the creation of weapons and defense systems.
Once thirty users join a group, the game would automatically start. Each person would be given a certain amount of health and as different weapons hit people through a bluetooth connection, your health would lower until you were finally dead. Your target would then be given to your assassin.
The paper does not explain any testing done, however it does hint at some based upon the reference to different types of phones and their bluetooth connection time. They say that this is a flaw in connection that needs to be addressed.
Thursday, March 22, 2012
Paper Reading #7: Calculation of probabilistic worst-case response-time for message in bluetooth
Umadevi Chezhian, U., Ramar, K., and Geetha, S. "Calculation of probabilistic worst-case response-time for message in bluetooth". Indian Journal of Science & Technology. Jul 2010. Vol. 3 Issue 7, p770-773.
This paper calculates the worst case response time for bluetooth transmission using calculations from the time relationship between 802.11 packets and bluetooth hops and the frequency distinction between a normal 802.11 direct sequence standard and the bluetooth frequency hops themselves.
There has been a release for bluetooth for adaptive frequency hopping (AFH) which decreased the number of collisions for packets. Once the interference and frequencies are calculated, bluetooth message sending will work just as if there were no interference in the network. The problem with this is the overhead it takes to establish this criteria.
In calculating the worst case, the first way they calculate is measuring the overlap in the packet sizes. The other way the overlap in the time period based on the frequency.
Their conclusion is that the number of bluetooth hop overlaps depends on packet length and time offset.
This paper calculates the worst case response time for bluetooth transmission using calculations from the time relationship between 802.11 packets and bluetooth hops and the frequency distinction between a normal 802.11 direct sequence standard and the bluetooth frequency hops themselves.
There has been a release for bluetooth for adaptive frequency hopping (AFH) which decreased the number of collisions for packets. Once the interference and frequencies are calculated, bluetooth message sending will work just as if there were no interference in the network. The problem with this is the overhead it takes to establish this criteria.
In calculating the worst case, the first way they calculate is measuring the overlap in the packet sizes. The other way the overlap in the time period based on the frequency.
Their conclusion is that the number of bluetooth hop overlaps depends on packet length and time offset.
Thursday, March 8, 2012
Paper Reading #6: An efficient algorithm for scheduling in bluetooth piconets and scatternets
Ramana Reddy, G., Bhatnagar, S., Rakesh, V., and Chaturvedi, V. "An efficient algorithm for scheduling in bluetooth piconets and scatternets". Wireless Networks (10220038). Oct2010, Vol. 16 Issue 7, p1799-1816.
The expressed algorithm sought to get increased throughput and reduced packet delays in bluetooth piconets and scatternets all the while maintaining relatively fair traffic flow. Using multi-layered parameterized policies, the algorithm schedules on the slave nodes of the network. The way the group scheduled the packets was based on the two-timescale simultaneous perturbation stochastic approximation (SPSA) algorithm.
The algorithm showed better performance in both piconets and scatternets in polling and data rates for bluetooth over conventional algorithms. While the performance was greater, I don't think it necessary to necessarily using this algorithm because the performance increase was not astoundingly significant.
The expressed algorithm sought to get increased throughput and reduced packet delays in bluetooth piconets and scatternets all the while maintaining relatively fair traffic flow. Using multi-layered parameterized policies, the algorithm schedules on the slave nodes of the network. The way the group scheduled the packets was based on the two-timescale simultaneous perturbation stochastic approximation (SPSA) algorithm.
The algorithm showed better performance in both piconets and scatternets in polling and data rates for bluetooth over conventional algorithms. While the performance was greater, I don't think it necessary to necessarily using this algorithm because the performance increase was not astoundingly significant.
Tuesday, February 28, 2012
Paper Reading #5: WiFi and Bluetooth fight for bandwidth
Quinnell, R. "WiFi and Bluetooth fight for bandwidth". EDN. 4 Aug 2005. Vol. 50 Issue 16, p73-78.
Quinnell states that WiFi and Bluetooth use the same frequencies of bandwidth and therefore could conflict for resources if not monitored. The conclusions showed that distance was the greatest factor determining interference among multiple agents trying to access the space. In 2005, when the paper was authored, the authors state that there was not much worry at the current time about these wireless technologies overlapping to cause problems because there were not many reasons that transponders would be in such close proximity, but predicted by market trends that this could be an issue in the future, which I believe we are seeing today.
One of the biggest challenges in this area seems to be VOIP. Bluetooth seeks to mitigate these challenges by using a method called frequency hopping, where the device can identify a frequency with traffic on it and tries to move to a less congested frequency. There are also approaches that coordinate the transmissions between the technologies as well as adjusting packet sizes.
Quinnell states that WiFi and Bluetooth use the same frequencies of bandwidth and therefore could conflict for resources if not monitored. The conclusions showed that distance was the greatest factor determining interference among multiple agents trying to access the space. In 2005, when the paper was authored, the authors state that there was not much worry at the current time about these wireless technologies overlapping to cause problems because there were not many reasons that transponders would be in such close proximity, but predicted by market trends that this could be an issue in the future, which I believe we are seeing today.
One of the biggest challenges in this area seems to be VOIP. Bluetooth seeks to mitigate these challenges by using a method called frequency hopping, where the device can identify a frequency with traffic on it and tries to move to a less congested frequency. There are also approaches that coordinate the transmissions between the technologies as well as adjusting packet sizes.
Tuesday, February 21, 2012
Paper Reading #4: Using short-range communication to control mobile device functionality
Moors, T., Mei, M., and Salim, A. "Using short-range communication to control mobile device functionality". Personal & Ubiquitous Computing; Jan2008, Vol. 12 Issue 1, p11-18.
The authors introduce the idea of ZoneIT, which is a system that allows for voluntary disabling of certain services of a mobile device within a short range zone. The idea is that in a cinema or something of the like, you want to be able to automatically silence your phone (by disabling the ringer). This is what ZoneIT seeks to do. It would have a manual override as to not hinder emergency situations such as a hijacking on a plane.
ZoneIT uses its own authentication system to sync up mobile devices. Mobile devices must be pre-programmed to have the public key for venues which they trust.
Their test involved a Sony Ericsson. One problem was the API did not allow the disabling of audio in the phone (but could mute vibrations). The developers worked around this by exploiting a bug in the audio engine.
They claim that everyone would benefit from the implementation of these zones.
The authors introduce the idea of ZoneIT, which is a system that allows for voluntary disabling of certain services of a mobile device within a short range zone. The idea is that in a cinema or something of the like, you want to be able to automatically silence your phone (by disabling the ringer). This is what ZoneIT seeks to do. It would have a manual override as to not hinder emergency situations such as a hijacking on a plane.
ZoneIT uses its own authentication system to sync up mobile devices. Mobile devices must be pre-programmed to have the public key for venues which they trust.
Their test involved a Sony Ericsson. One problem was the API did not allow the disabling of audio in the phone (but could mute vibrations). The developers worked around this by exploiting a bug in the audio engine.
They claim that everyone would benefit from the implementation of these zones.
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