Application Scenario
• Each user is equipped with Nt transmit antennas
• WAR (Wireless Access Router) is equipped with Nr receive antennas
System’s Architecture
VBR media
Encoder
r ( (t ), s (t ), q (t ))
 ( (t ), s (t ), q (t ))
N1
s (t )
LB
R
V(t)
 (t )
Wireless
Loss-affected MAC queue
VBR
media
Decoder
 ( (t ), s (t ), q (t ))
q(t )
N2
Connection
Physical layer configuration
D.N.Tse, P.Viswanath, L.Zheng,’’ Diversity-Multiplexing Tradeoff in Multiple-Access Channels’’,
IEEE Tr.on Inform. Theory, vol.50, no.9, pp.1859, 2004.
Diversity-vs-Multiplexing-vs-SDMA tradeoff
• The best diversity-multiplexing
curve attainable by the MIMO MAC
channel
FER
(i )
 ( ave )
d
i-th average Frame Error Rate at
the MAC layer
Piecewise linear curve
 Nt , Nr ( s ), 0   s   N r / U  1

*
d ( s )  UNt , Nr (U s ),  N r / U  1   s  min  N t ; N r / U 

0,  s  min  Nt ; N r / U 
MIMO MAC Packet loss



2
2 
2
i 

 1   1   1  
R  t 
max  1
i 


 L t  



 i  




i


LB  R  t 
 Ri   t    R  t     min   max   


2

1







max




MIMO MAC service rate


TsWH
min Nt rc M c ; s log 2  z (i ) (lt ) ave   0 (byte / slot )
8
0  0*  s log 2 Nt  log 2  det CovR   log 2  det CovT  (bit / sec./ Hz )
R(i ) (lt ) 
Multiple User Systems
MISO System
MIMO System
Backbone
Access Point
Client Device
Dynamic resource
allocations
Joint
optimization
MISO Systems - Multiplexer
S1
.
..
aM
Queue weights depending
on the Class of Service
of the different input
streams
S2
.
..
a1
a2
Wireless
channel
t
SM
Weights
Optimization problem
7
The radiated energies and the system state partitioning for the jointly
optimal scheduler
8