D: because well , l probably y what you will have will be some neighbors that are really close
C: Hmm .
D: others that are a little bit far away
D: and finally , these neighbors that are in the  in the frontier of your of your coverage area .
D: OK .
C: Hmm .
D: Yeah .
C: OK , this is a question not directly related to these things ,
C: but maybe that 's why maybe only a short answer .
C: Uh , do you assume that power control will be issue also in the next years ?
C: In other words , um is the um success of having more power within the devices in maybe three year , four years , five years , for batteries , and and and @ @ and sofort so on
C: uh will it be succeeded that you have so much power available that this difficult mechanism who is in the wireless network will be uh out of scope ?
D: Mmm .
D: Yeah .
C: Because if I have a device which uh can I use maybe for twenty - four hours ,
C: I do not have , in principle , really the constraint to uh deal with with uh power savings .
D: Yeah , let let me let me answer you uh with a question .
D: Uh , If , for example , your car uh you you have uh an endless uh source of of gas , do you think it will it will be a problem , the amount of gas your your car is is using ?
D: OK .
D: It won't be a problem for your pocket ,
D: for your wallet ,
D: but maybe it will be a problem for the environment .
D: So , I think that the answer to your question is in this line ,
D: that uh if you have an endless uh source of power , well , maybe it 's not a problem , for the battery uh lasting .
D: But , it is a problem because you are using more area than you should .
D: And therefore you are preventing other transmissions to take place at the same time .
D: And therefore uh the problem is not only connected to to the to the power
D: it is also connected to the net to the global network throughput .
D: OK ?
C: OK .
D: So D: But , again , uh , you know , uh the the m
D: If you ask me " what what do you think what will happen , in the industry ? "
D: What I think that will happen is that they will try to get uh mmm better hardware than we have now
D: because now the problem with transceivers is that a lot of power is uh consumed at the logic of the transceiver ,
D: and not uh transmitted to the air .
D: It is not power transferred to the air .
D: So , the problem now is that eh most of the power uh , uh t uh a wireless network card is consuming , is is is drawn by the by the eh logic control of the card .
C: Yeah .
D: All the all the calculations ,
C: That 's what I D: all the hardware C: Yeah , that was the reason I 'm talking about this is uh D: So , I am sure that eh that manufacturers will try to to squeeze until the the  the last ampere f of  of this eh , let 's say , eh wasted power ,
D: because what you cannot avoid is , uh
D: to p l the part of the of the radio frequency power you have to transmit .
D: I mean , this is this cannot be avoided .
D: But what you can avoid or you can reduce
D: and probably
D: because now it is the main factor , the main consumption factor , is the logic inside .
D: In the same way , at as as it happened with with processors , for example .
D: Now processors are much more uh power efficient than before .
D: OK ?
C: Yeah , but anyway , that was the reason for my question .
C: If I save with a lot of difficult mechanism , within the air interface and between the base station or access point and the mobile node , one percent of the power whereas ninety - nine percent is consumed by packet processing
C: and and and and uh uh C P U or whatever ,
D: Mm - hmm .
C: uh is it worth to have it ?
C: If I really , with a normal device uh with a battery lifetime of maybe twenty - four hours , thirty - six hours or whatever kind of thing And I think it will be increased .
C: As the more mobile nodes are in the world the better the battery will be .
C: So that 's was the reason for my question .
D: Yeah , pero e
C: Yeah , yeah , yeah .
D: uh but D: Oh , sorry !
D: But even if you if you don't have to to worry about eh your power source , you have to worry about your environment ,
D: about not using more resources that you don't own
C: Yeah .
C: Yeah .
D: that are uh shared about w w among the community .
C: Yeah , I g got it .
C: Yeah .
C: Yeah .
C: OK .
E: Excuse me @ @ .
D: OK .
E: If I understood correctly , the mechanism eh you should eh look for um the minimum eh coverage range
D: Yeah .
E: in order to maximize the throughput of the network .
D: Yeah .
E: So there the the power control eh algorithm should work , in order to use at each instant of time the minimum power need to reach
D: The destination .
E: the neighbor .
E: That Because this is the way eh eh more transmissions uh
E: may take take place at the same time .
D: Can take place at the same time .
C: Yeah , yeah , yeah , yeah .
E: So you need the adaptive mechanism to minimize the coverage range .
C: Yeah .
D: That 's OK .
D: And to and to get the maximum network throughput .
E: That D: That 's that 's the idea .
D: However however , and
D: uh , it is always some however ,
D: uh by applying this uh greedy mechanism , in in D: or , more than greedy in this case ,
D: it could be , say , this stingy mechanism to trying to avoid to use any extra space is also leading to a higher level of interference at the receivers .
D: So , uh
D: at the end of the road , we have to uh look for some trade - offs to avoid too much uh interference at the receivers .
D: OK ?
D: So , uh at the end we are using a little bit more power than these mathematically minimum values .
D: OK ?
D: because if not , the uh
D: the frame error rate or the bit error rate uh , skyrockets .
C: Mm - hmm .
D: OK ?
D: because of the of high interference levels .
D: A lot of simultaneous transmissions also means for each receiver point of view , a lot of neighbors or or nodes transmitting at the same time .
D: And , all the transmitters uh with the exception of the transmitter of my transmitter , are my intereferers
D: and are  and all of them are producing less quality reception ,
D: so if they are a lot of them , well , uh the reception can be can be uh disturbed .
D: OK ?
D: And  but um , um this is taking longer than I expected .
D: OK .
D: Let 's let 's uh take a k a a really a really light uh view at the at the routing in this in this network ,
D: which is another important area of of research .
D: You know , in fact there is a a group at the ITF <nonvocalsound> uh called " Manit " .
D: This working group is is devoted to uh try to to present or to agree a common protocol for routing IP traffic on these eh kind of networks ,
D: on these ad - hoc networks ,
D: Uh , and
D: at this moment there are , I would say , a lot of proposals of different protocols uh for uh end - to - end traffic
D: and also for multicast traffic ,
D: on these networks
D: And eh well some day in the future eh , a protocol should be chosen
D: but , for the moment eh we have several of them on the table .
D: and eh any protocol has some advantages and some disadvantages .
D: The basic  the basic problem we have to solve in in these eh routing protocols is the fast eh  the fast pace at what eh topology changes can happen .
D: So
D: the problem here is that now uh one node is my neighbor ,
D: and next second , it is not .
D: So any route that was going through this neighbor now is is not possible
D: and should change .
D: And the problem is that well
D: uh an
D: an if you let me a personal comment , I think that one error on the group is not to agree a set of mobility patterns to to do the  the tests .
D: because here , well , mobility is making these uh neighborhood relationships to appear or to disappear ,
D: So uh , it should be interesting if we agree uh a common a common set of motion patterns to perform the tests
D: because if not , well , it 's difficult to  to perform comparisons uh between one protocol and another ,
D: a different one .
D: But anyway , now what we have is is two basic approaches to this  this problem .