Algorithm 4. Cluster Member Association and FCH Selection (CMA-FCHS)
	Run at any non-CH node (e.g., w) Input: the hello messages of all neighbors Output: the membership request message
1.	for each entry (IDu, du,w) in Lw,nei do
2.	if the state variable su is “decided MCH” then initialize the flag variable fu as “unrequested”
3.	end for
4.	dmin = maximum number; IDmch = maximum number
5.	for each entry (IDu, du,w) in Lw,nei do
6.	if (fu == “unrequested”) and ((du,w < dmin) or (du,w == dmin && IDu < IDmch)) then {dmin = du,w; IDmch = IDu}
7.	end for
8.	Send the “membership request message” to the neighboring MCH with IDmch
9.	if receive the “membership list message” from the neighboring MCH with IDmch (e.g., y) then
10.	if find that its ID (i.e., w’s ID) is not in the “membership list message” then
11.	if not more than the given maximum number of resending attempts then
12.	fy = “requested”
13.	Go to step 4
14.	end if
15.	end if
16.	end if
	Run at a MCH node (e.g., u) which has a SCH node (e.g., v) Input: the hello messages of all neighbors Output: the membership list message
17.	if receive the first “membership request message” from any non-CH node (e.g., w) then
18.	Compute node w’s FCH eligibility metric FMw,v,u according to the Formula (9)
19.	FMmax = FMw,v,u; IDfch = IDw
20.	Add IDw to the membership list message
21.	Set the timer tφ as φ
22.	while the timer tφ does not expire do
23.	if receive the “membership request message” from any non-CH node (e.g., x) then
24.	if the number of cluster members is less than the threshold then
25.	Add IDx to the membership list message
26.	Compute node x’s FCH eligibility metric FMx,v,u according to the Formula (9)
27.	if (FMmax < FMx,v,u) or (FMmax == FMx,v,u && IDx < IDfch) then {FMmax = FMx,v,u; IDfch = IDx}
28.	end if
29.	end if
30.	end while
31.	Declare the node with IDfch as the FCH through adding it to the membership list message
32.	Design a TDMA schedule and add it to the membership list message
33.	Broadcast the “membership list message” to its neighbors within the cluster radius
34.	else if a new non-CH wants to join a given MCH and the number of cluster members is less than the threshold then
35.	Update the TDMA schedule to include this node’s ID and add it to the “membership list message”
36.	Broadcast the updated “membership list message” to its neighbors within the cluster radius
37.	end if