A base station system, comprising a first field replaceable unit, FRU, (600a, 700a, 800a, 900a, 1000a, 1100a, 1200a, 1300a, 1400a, 1500a, 1600a1 to 1600am, 1700a) and a second FRU (600b, 700b, 800b, 900b, 1000b, 1100b, 1200b, 1300b, 1400b, 1500b, 1600b1...1600bm, 1700b), wherein: the first FRU comprises: a radio frequency/intermediate frequency, RF/IF, module (601, 701, 801, 901, 1001, 1101, 1201, 1301, 1401, 1501, 1701), configured to perform conversion between an RF signal and a base band, BB, signal; a first BB module (603, 703, 803, 903, 1003, 1103, 1203, 1303, 1403, 1503, 1603a1 to 1603m, 1703), connected to the RF/IF module, configured to process a first part of the BB signal according to a preset configuration rule for processing data; and a first interface module (605, 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505, 1705) connected to the second FRU; the second FRU comprises: a second BB module (609, 709, 809, 909, 1009, 1109, 1209, 1309, 1409, 1509, 1609b1 to 1609bm, 1709), configured to process a BB signal other than the first part of the BB signal according to the preset configuration rule for processing data; and a second interface module (607, 707, 807, 907, 1007, 1107, 1207, 1307, 1407, 1507, 1707) connected to the first FRU; wherein the first BB module in the first FRU and the second BB module in the second FRU are adapted so that one part of BB functions is processed by the first BB module in the first FRU and the other part of the BB functions is processed by the second BB module in the second FRU, wherein the BB functions comprise one or more of encoding, decoding, modulating, demodulating, spreading, and dispreading. a radio frequency/intermediate frequency, RF/IF, module (601, 701, 801, 901, 1001, 1101, 1201, 1301, 1401, 1501, 1701), configured to perform conversion between an RF signal and a base band, BB, signal; a first BB module (603, 703, 803, 903, 1003, 1103, 1203, 1303, 1403, 1503, 1603a1 to 1603m, 1703), connected to the RF/IF module, configured to process a first part of the BB signal according to a preset configuration rule for processing data; and a first interface module (605, 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505, 1705) connected to the second FRU; the second FRU comprises: a second BB module (609, 709, 809, 909, 1009, 1109, 1209, 1309, 1409, 1509, 1609b1 to 1609bm, 1709), configured to process a BB signal other than the first part of the BB signal according to the preset configuration rule for processing data; and a second interface module (607, 707, 807, 907, 1007, 1107, 1207, 1307, 1407, 1507, 1707) connected to the first FRU; wherein the first BB module in the first FRU and the second BB module in the second FRU are adapted so that one part of BB functions is processed by the first BB module in the first FRU and the other part of the BB functions is processed by the second BB module in the second FRU, wherein the BB functions comprise one or more of encoding, decoding, modulating, demodulating, spreading, and dispreading. a second BB module (609, 709, 809, 909, 1009, 1109, 1209, 1309, 1409, 1509, 1609b1 to 1609bm, 1709), configured to process a BB signal other than the first part of the BB signal according to the preset configuration rule for processing data; and a second interface module (607, 707, 807, 907, 1007, 1107, 1207, 1307, 1407, 1507, 1707) connected to the first FRU; wherein the first BB module in the first FRU and the second BB module in the second FRU are adapted so that one part of BB functions is processed by the first BB module in the first FRU and the other part of the BB functions is processed by the second BB module in the second FRU, wherein the BB functions comprise one or more of encoding, decoding, modulating, demodulating, spreading, and dispreading.