A New Subcarrier Allocation Strategy for MIMO-OFDMA Multicellular Networks Based on Cooperative Interference Mitigation

Algorithm 1

The proposed subcarrier allocation strategy.

(1) Step  1.  𝐒 = {1,2,…,𝑆}, 𝐂_BS = 𝐒, 𝐂_sec = 𝐒, 𝐂𝐀𝐒 = 𝐒, 𝑛 = 0

(2) Step  2. 𝑛←𝑛+1. MS 𝑛 tries to access the network in 𝑏th BS and 𝑘th sector,

 requesting 𝑈_𝑛 subcarriers (𝑆_𝑛← {}):

(3) 𝐴_SC← 𝐂_sec,𝑘∩𝐂𝐀𝐒_𝑘

(4) If 𝐴_SC < 𝑈_𝑛 go to Step  3, else:

(5) For 1≤𝑗≤𝑈_𝑛

(6)   SC← 𝐴_SCargmax_{𝑗′∈𝐴SC}𝐇_{𝑛,sec(𝑛),𝑗′}²_𝐹

(7)   𝐴_SC← 𝐴_SC∖SC

(8)   𝐂𝐀𝐒_AS(𝑘)← 𝐂𝐀𝐒_AS(𝑘)∖SC

(9)   𝐂_sec,𝑘← 𝐂_sec,𝑘∖SC

(10)   𝐂_BS,𝑏← 𝐂_BS,𝑏∖SC, 𝑆_𝑛← 𝑆_𝑛∪ SC

(11)   𝐰_𝑛,SC←𝐗𝜆_𝑚𝐇^𝐻_{𝑛,sec(𝑛),SC}𝐇_{𝑛,sec(𝑛),SC}

(12) end

(13) Then go to Step  5

(14) Step  3. 𝐴_SC← 𝐂_BS,𝑏

(15)  If 𝐴_SC ≥ 𝑈_𝑛 go to Step  4, else 𝐴_SC← 𝐂_sec,𝑘

(16)  If 𝐴_SC < 𝑈_𝑛 go to Step  6 (blocking has occurred)

(17) Step  4.

(18) For 1≤𝑗≤𝑈_𝑛

(19)   SC← 𝐴_SCargmax_{𝑗′∈𝐴SC}SJNR_𝑛,𝑗′

(20)   𝐴_SC← 𝐴_SC∖SC,

(21)   𝐂_sec,𝑘← 𝐂_sec,𝑘∖SC

(22)   𝐂_BS,𝑏← 𝐂_BS,𝑏∖SC

(23)   𝑆_𝑛← 𝑆_𝑛∪ SC

(24)   𝐰_𝑛,SC=𝐗𝜆_𝑚𝐇^𝐻_{𝑛,sec(𝑛),SC}𝐇_{𝑛,sec(𝑛),SC}

(25) end

(26) Step  5. (Power Control):

(27) For 1≤𝑗≤𝑈_𝑛

(28) 𝑠← 𝑆_𝑛(𝑗)

(29) 𝑁_𝑠← find(𝑠∈𝑆_𝑛′), 1≤𝑛^′≤𝑁

(30) 𝐩_𝑠← 1 (𝑁_𝑠, 1) × (−1)

(31) while (find(𝐩_𝑠<0)>0)

(32)  Define 𝑁_𝑠 × 𝑁_𝑠 matrix 𝐀_𝑠 and 𝑁_𝑠 × 1 matrix 𝐁_𝑠:

(33)   𝐀_𝑠𝑛,𝑛^′=𝛿_𝑛𝑛′+SINR_𝑠𝛿_𝑛𝑛′𝐰−1^{𝐻𝑛′,𝑠}𝐇_{𝑛,sec(𝑛′}^𝐻_),𝑠𝐫^𝐻_𝑛,𝑠𝐫_𝑛,𝑠𝐇_{𝑛,sec(𝑛′),𝑠}𝐰_𝑛′,𝑠TL_{𝑛,sec(𝑛′)}

(34)   𝐁_𝑠(𝑛)=𝐫^𝐻_𝑛,𝑠𝐫_𝑛,𝑠𝐼_𝑜SINR_𝑠,  𝐩_𝑠=𝐀_𝑠⁻¹𝐁_𝑠

(35)  If(find(𝐩_𝑠<0)>0)‖(find(𝐩_𝑠>𝑝_max) > 0)

(36)   If (find(𝐩_𝑠<0) > 0)

(37)    𝐑_𝑠← find(𝐩_𝑠<0)

(38)   else

(39)    𝐑_𝑠← find(𝐩_𝑠>𝑝_max)

(40)   end

(41)   MS_𝑟← 𝐑_𝑠(1) (MS_𝑟 is removed from the network)

(42)   remove_counter ←remove_counter + 1

(43)   𝑁_𝑠← find(𝑠∈𝑆_𝑛′), 1≤𝑛^′≤𝑁

(44)   𝐩_𝑠← ones(𝑁_𝑠, 1) × (−1)

(45)  end (line 35)

(46)   end (line 31)

(47) end (line 27)

(48) Step  6.

(49)  p_blocking ←remove_counter/𝑛

(50)  If p_blocking < p_blocking_max then go to Step  2