1. A method for handling hybrid automatic repeat request (HARQ) operations for aggregated carriers comprising: determining a total number of soft buffer bits of a soft buffer to be partitioned; obtaining a plurality of carrier-dependent weighting factors corresponding respectively to a plurality of aggregated carriers; and partitioning the soft buffer based at least in part on the carrier-dependent weighting factors to obtain a plurality of separate soft buffers for each of the plurality of aggregated carriers, the partitioning comprising selecting a soft buffer partition size based partly on at least one of: N IR , k = [ N soft ( ∑ m = 0 N carrier - 1 ⁢ K MIMO , m ⁢ W m · min ⁡ ( M DL HARQ , m , M limit , m ) ) / W k ] , N IR , k = [ N soft K MIMO , k ⁡ ( ∑ m = 0 N carrier - 1 ⁢ · W m · min ⁡ ( M DL HARQ , m , M limit , m ) ) / W k ] , N IR , k = [ N soft ( ∑ m = 0 N carrier - 1 ⁢ K MIMO , m ⁢ N RB , m DL · min ⁡ ( M DL HARQ , m , M limit , m ) ) / N RB , k DL ] , or N IR , k = [ N soft K MIMO , k ⁡ ( ∑ m = 0 N carrier - 1 ⁢ · N RB , m DL · min ⁡ ( M DL HARQ , m , M limit , m ) ) / N RB , k DL ] , Wherein N IR,k is the soft buffer memory partition size for the k th carrier; N soft is the total number of soft buffer bits for a specified UE category; N carrier is the total number of aggregated carriers; W m is a relative carrier-dependent weighting factor for the m th carrier; N RB,m DL is a carrier bandwidth factor indicating the bandwidth of the m th carrier; K MIMO,m is the maximum number of transport blocks for the m th carrier that are transmittable to a user equipment device in one transmission time interval; M DL _ HARQ,m is the maximum number of downlink hybrid automatic retransmit request processes for the m th carrier; and M limit,m is the configured maximum number of hybrid automatic retransmit request processes for the m th carrier.