Incentives - Peer-to-Peer Computing: Applications, Architecture, Protocols, and Challenges - page 118

TABLE 5.4: Technical specifications of a typical server interface.

GTRAN DotSurfer 6210 [GTRAN, 2009]
(1xEV-DO Release 0)

Voltage 3.3V

Receive current 150mA

Receive power 495mW

Data rate 2.4Mbps

TABLE 5.5: Technical specifications of a typical peer interface.

Cisco AIR-CB21AG [Cisco, 2009]
(IEEE 802.11a/b/g)
Voltage

3.3V

Transmit current 530mA

Transmit power 1749mW

Receive current 282mA

Receive power 930.6mW

Data rate 54Mbps

For example, α x > 1 means that x is willing to consume more energy than the
cost of subscribing to all n stripes (E R s (n)), e.g., a mobile device equipped
with plentiful energy resources. On the other hand, α x ≤1 means that x is
more concerned with the energy cost than the streaming quality, e.g., a mobile
device with little residual energy. Specifically, the value of α x determines the
number of stripes client x would subscribe to. Since the n stripes are assumed
to be of equal rate, i.e., r/nkbps, the energy cost of streaming i stripes via
the server interface is:

n × P RX

i

E RX
s

s
R s ×r×t

(i) = (5.48)

This implies that client x would stream up to i stripes from the server if
α x ≥α 1 (i), where α 1 (i) is given by:

E R s (i)
E RX
s

i
n

α 1 (i) = = (5.49)

The set of α 1 (i), i∈[0, n], are the threshold values when client x inde-
pendently streams from the server. Figure 5.21 shows the variation of the
number of subscribed stripes with the type of client for n = 10. For exam-
ple, if α x = 0.55, client x would subscribe to 5 stripes from the server. This
represents the performance of media streaming when each client acts inde-
pendently. However, neighboring clients could utilize their peer interfaces to
improve streaming performance without violating their energy consumption