Patent ID: 7352800

Claim:
A method of Partial Parallel Interference Cancellation (PPIC) for recursively eliminating Multiple Access Interference of a received signal for a receiver, including the following steps: A: receiving a system delay parameter and offering a recursion parameter; B: building a related matrix based on the system delay parameter, wherein, ℜ k × k = ⌊ r i , j ⌋ r i , j = { ρ i , j ( m ) , i < j ρ j , i ( v ) , i > j ⁢ ⁢ ρ i , j ( m ) = 1 T ⁢ ∫ 0 T -  τ i - τ j  ⁢ a i ⁡ ( t ) ⁢ a j ⁡ ( t +  τ i - τ j  ) ⁢ ⁢ ⅆ t ⁢ ⁢ ρ i , j ( v ) = 1 T ⁢ ∫ T -  τ i - τ j  T ⁢ a i ⁡ ( t ) ⁢ a j ⁡ ( t +  τ i - τ j  - T ) ⁢ ⁢ ⅆ t k means the total users in the system, i means the i th user, j means the j th user, a i means the spreading codes of the i th user, a j means the spreading codes of the j th user, τ i means the delay time of the i th user, τ j means the delay time of the j th user; C: computing an input parameter Z i,w (0) : Z i , w ( 0 ) = 1 T ⁢ ∫ wT + τ i ( w + 1 ) ⁢ T + τ i ⁢ r ⁡ ( t ) ⁢ a i ( t - wT - τ i ⁢ ) ⁢ ⅆ t wherein, Z i,w (0) means the w th bit value of the i th user, r(t) means the received signals; D: setting an executive parameter equal to 1, expressed as s=1; E: computing a result value, which can be shown as: Z i , w ( s ) = ⁢ Z i , w ( 0 ) - P s ⁢ { ∑ l = 1 k - 1 ⁢ [ Z l , w ( s - 1 ) ⁢ ρ i , l ( m ) + Z l , w + 1 ( s - 1 ) ⁢ ρ i , l ( v ) ] + ⁢ ∑ l = k + 1 K ⁢ [ Z l , w ( s - 1 ) ⁢ ρ i , l ( m ) + Z l , w - 1 ( s - 1 ) ⁢ ρ i , l ( v ) ] } wherein, P s means the Partial Factor of the STAGE s; F: determining whether the executive parameter is the recursion parameter; G: If the executive parameter is the recursion parameter, then outputting Z i,w (s) from the receiver; H: If the executive parameter is not the recursion parameter, then increasing 1 to the executive parameter and then executing step E.