Protocol Cooperation decision Centralization CD-MAC Transmitter Centralized rDCF
Receiver Distributed CODE Transmitter Centralized CoopMAC Transmitter Centralized UtdMAC Relay Centralized AMCCR Relay Distributed Protocol Selection overhead CD-MAC Preselect, historical information rDCF
Preselect, historical information CODE Periodic broadcast CoopMAC Passive monitoring UtdMAC Preselect AMCCR RTS-CTS contention Protocol Network coding functionality Number of QoS metrics CD-MAC No Single rDCF
No Single CODE Partial Single CoopMAC No Single UtdMAC No Single AMCCR Yes Multiple Table 3: Simulation parameters in the MAC layer.
where [FU.sub.gp] is feed unit for growing pig; [FU.sub.gs] is feed unit for gestating sow, RDCP is in vitro ileal digestible CP, RDCF
is calculated ileal digestible fat, IDC is ileal digestible carbohydrate, FC is fermentable carbohydrate and EUD[M.sub.i] is enzyme undigested ileal DM, where FU is expressed on a DM basis and other components are based on g/kg DM.
: A relay-enabled medium access control protocol for ad hoc networks," IEEE Trans.
where FU is expressed on a DM basis and other components are based on g/kg DM; RDCP = in vitro ileal digestible CP, RDCF = calculated ileal digestible fat, EDC = in vitro ileal digestible carbohydrates, FERMC = fermentable carbohydrates, EIDMi = enzyme-undigested ileal DM.
Calculations of energy values for diets in the potential physiological energy (PPE) system (1) Nutrient Energy fraction Calculation of fractions (g/kg) factor (kJ/g) RDCP (2) CP x EDN (7)/100 9.9 RDCF (3) Crude fat x 0.9/100 31.7 EDC (4) OM (8) x EDOMi (9)/100-(RDCP + RDCF) 11.7 FERMC (5) OM x (EDOM (10)-EDOMi)/100 7.0 EIDMi (6) OM x (100-EDOMi)/100 + 0.3 x Ash -2.8 (1) Derived from Boisen (2007).
Overall procedures of the rDCF scheme and the CoopMAC scheme to exchange control and data frames are quite similar but it is noticeable that the CoopMAC protocol clearly explains its procedure to choose helper nodes using mathematical equations.
The probability of CRTS frame transmission failures in the NC-MAC protocol can be described as [p.sub.f]([p.sub.f] = [p.sub.m] + [p.sub.c] - [p.sub.c] [p.sub.m]), the same as in the rDCF, the CODE or, the CoopMAC protocol where the CRTS frame collision probability [p.sub.c] can be obtained with [p.sub.c] = 1 - [(1 - [tau]).sup.K-1].
Performance comparisons of the NC-MAC protocol with the DCF and the rDCF protocol under variations of different system parameters, the data length, and the number of source nodes, are depicted in Fig.