Information Technology Reference
In-Depth Information
Chapter 3
SGUM-based Random Access Control
and Power Control
In this chapter, we study the application of the SGUM framework to two classical
problems for wireless networks: random access control and power control.
3.1
Introduction
Wireless spectrum is a limited resource shared by wireless users. Due to the broadcast
nature of wireless communication, wireless nodes in physical proximity are subject
to interference to each other if they transmit concurrently on the shared wireless
spectrum. Multiple access methods have been developed to allow wireless nodes
to share the use of wireless resources in an interference-free manner. In contrast to
contention-free multiple access (e.g., TDMA, FDMA) which relies on centralized
coordination, contention-based random access allows contending wireless nodes to
share wireless spectrum in a distributed manner. On the other hand, interference-free
environment may not be available in some wireless networks. For example, in
CDMA systems, perfect orthogonality among users' transmit signals is difficult to
achieve, and thus a user's transmission is affected by the interference power received
from other users. In interference-limited wireless networks, power control represents
a key degree of freedom for network design and optimization. Game theory has been
extensively applied to study the strategic decision making among autonomous and
rational users for both random access control and power control. A survey of random
access control games and power control games can be found in [
1
] and [
2
], respec-
tively. To stimulate user cooperation for efficient spectrum sharing, we cast random
access control and power control among userswith social ties as SGUM games.
3.2
SGUM-based Random Access Control
3.2.1
System Model
We consider a set of users under the protocol interference model, where each user
i
is a link consisting of transmitter
T
i
and receiver
R
i
. For example, in Fig.
3.1
,
T
1
interferes with
R
2
,
T
2
interferes with
R
1
,
T
3
interferes with
R
1
, where dashed circles
