MCBC Contention using OFDM subcarriers

1
MCBC Contention using OFDM subcarriers

• Cross-layer
• activates senses the energyof individual OFDM
  subcarriers
• Fast node elimination withfeedback algorithm
• Non-adaptive
• contention parameters remainconstant
• Design goals
• Low collision overhead
• Robust in both ad-hoc infrastructure
• Reliable QoS provision

B. Roman et al. "Multi-Carrier Burst Contention
(MCBC) Scalable Access Control for Wireless
Networks," in IEEE WCNC, 2008
IEEE WCNC08, Las Vegas, Apr 2008 IEEE PIMRC09,
Tokyo, Sep 2009
2
MCBC Data exchange

• Synchronized fixed duration contention windows
  (CW)
• Hidden node mitigation with no additional
  overhead
• Does not require RTS/CTS

IEEE WCNC08, Las Vegas, Apr 2008 IEEE PIMRC09,
Tokyo, Sep 2009
3
MCBC - Contention algorithm
Round 1 (feedback) referees select the 34
nominees as winners
Round 2 (contention) 34 contenders flip a coin
(probability pt)
Round 1 (contention) 250 contenders flip a coin
(probability pt)
Round 2 (feedback) referees select the 5
nominees as winners
Round 3 (contention) 5 contenders flip a coin
(probability pt)
Round 3 (feedback) referees select the 1 nominee
as winner
Round 1 (contention) 34/132 nominees choose the
highest subcarrier
Round 2 (contention) 5/18 nominees choose the
highest subcarrier
Round 3 (contention) 1/3 contenders chooses the
highest subcarrier
Nominees 132
Referees 118
Referees 216
Referees 232
Referees 245
Referees 247
Referees 249
Nominees 3
Nominees 34
Nominees 18
Nominees 5
Nominees 1
Contenders 250
Contenders 34
Contenders 5
IEEE WCNC08, Las Vegas, Apr 2008 IEEE PIMRC09,
Tokyo, Sep 2009