A Game-Theoretical Approach for Spectrum Efficiency Improvement in Cloud-RAN

Algorithm 1

The proposed RRHs cooperation algorithm.

Stage 1: Initialization

 The network is partitioned by at the

 beginning time. For each , to initialize the variable as

 the empty set.

Stage 2: Coalition Formation

 do

  for each RRH   in  

   for each    in  

    if    then

     (a) If the (11) in Condition 1, (12) in Condition 2,

        (13) in Condition 3and are satisfied

         at the same time, then record the coalition .

    end if

   if all recorded is not a empty set then

    (a) After traversing all the possible coalitions in ,

       the optimum is found.

    (b) RRH decides to perform the hedonic shift rule

       from current coalition to the optimal one .

       () RRH updates the history variable by

          adding the old coalition to the .

       () RRH leaves its current coalition and

         joins the new coalition .

       () is updated,

        .

   end if

   end for

    end for

 until the coalition structure is stable.

Stage 3: Cooperative Transmission

 All the RRHs transmit signals cooperatively, which is

 controlled by a coalition-level scheduler in a hybrid multiple

 access mode.