Method, System and Devices for Reducing Interferences in OFDMA Wireless Communication Networks

摘要

A system and method for reducing interferences in OFDM networks comprising
generating (31) a set of pseudo-random coordination patterns {kin; i=0, . . . , N−1; n=0, . . . , M−1}, wherein kin are integers from 0 to M−1, M is the number of calls in a coordination cluster, N is the number of subcarriers, n is a cell identifier within the coordination cluster, and kin≠kim∀n≠m, i=0, . . . , N−1;generating a randomizing pattern common to all cells within the coordination cluster, comprising an invertible transformation in the time domain of the complex symbols for each subcarrier;spreading (32) the complex symbols over M TTIs:;b[i,m]=M∑m=0T-1a[i,n]exp[-j2π(Mn+ki)·m/(M·T)].;wherein a[i,n] denotes the symbols prior to the spreading (32), b[i,m] denotes the symbols after the spreading (32), 0≦k1≦M−1, i=0, . . . , N−1, m=0, . . . , T·M−1;
scrambling (34) the spread symbols b[i,m] to all the cells within the coordination cluster; andmapping (35) the scrambled symbols over all the N subcarriers in the frequency domain and M consecutive TTis in the time domain.

主权项

1. A method for reducing interferences in Orthogonal Frequency Division Multiplexing wireless networks, the method comprising:
from multiple base stations of a Orthogonal Frequency Division Multiplexing network, transmitting a number N of subcarriers and a number T of complex symbols in a time transmission interval;and the method being characterized by further comprising:
grouping a plurality of cells, which a user equipment communicating with at least one of the multiple base stations belong to, into coordination clusters defined as non-overlapping sets of cells, wherein each cluster comprises a number of cells whose transmissions are synchronized in the time domain; generating, for each of the coordination clusters, a set of pseudo-random coordination patterns {kin; i=0, . . . , N−1; n=0, . . . , M−1}, wherein kin are integers from 0 to M−1, M is the number of cells in the coordination cluster, N is the number of subcarriers, n is a cell identifier within the coordination cluster, and kin≠kim∀n≠m, i=0, . . . , N−1; generating, for each of the coordination clusters, a randomizing pattern common to all cells within the coordination cluster, the randomizing pattern comprising an invertible transformation of the complex symbols in the time domain along M consecutive transmission time intervals for each subcarrier; applying, by each cell within the coordination cluster, a spreading operation of the complex symbols over M consecutive transmission time intervals for each subcarrier according to the expression:b[i,m]=M∑n=0T-1a[i,n]exp[-j2π(Mn+ki)·m/(M·T)], wherein a[i,n] denotes the complex symbols prior to the spreading operation, b[i,m] denotes the complex symbols after the spreading operation, ki are integers comprising the coordination pattern of the cell with 0≦ki≦M−1, and i,m are indices given by i=0, . . . , N−1, m=0, . . . , T·M−1; applying, by each cell within the coordination cluster, an invertible scrambling operation of the spread complex symbols b [i,m] over M consecutive transmission time intervals in the time domain for each subcarrier, the scrambling operation being given by the randomizing pattern and common to all the cells within the coordination cluster; and mapping the scrambled complex symbols over all the N subcarriers in the frequency domain and M consecutive transmission time intervals in the time domain, obtaining precoded complex symbols after the spreading operation and the scrambling operation which are mapped on M·T consecutive resources in the time domain for each subcarrier.