Wireless Base Station Apparatus and Wireless Communication System Using That Apparatus

• US 20080253355A1
• Filed: 09/30/2005
• Published: 10/16/2008
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: TCL Communication Technology Holdings Ltd. (TCL Technology Group Corp.)
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Tominaga, Tsuyoshi, Fukunaga, Takeshi, Satou, Kunio, Ohnaka, Yasuhiro
• Granted Patent: US 8,139,557 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2605 Symbol extensions, e.g. Zero Tail, Unique Word [UW]
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 92/20 between access points

Abstract

A radio base-station apparatus with improved frame transmission efficiency by avoiding interference of preambles and frame control information between sectors of a cell or between cells with a frequency reuse factor. In the apparatus OFDMA multiple-access processing is performed for each of a plurality of sectors of a cell, and frames made of logical subchannel numbers and OFDMA symbol numbers are configured in synchronization respectively for the plurality of sectors, and offsets are added to the beginnings of given frames such that the preambles and frame control information arranged sequentially from the beginnings of the frames do not overlap on the OFDMA symbol numbers.

Claims

1. A radio base-station apparatus configured to work with a frequency reuse factor 1 in which a cell is divided into a plurality of sectors and said plurality of sectors are used with a same radio frequency, said radio base-station apparatus performing OFDMA multiple-access processing for each of said plurality of sectors, and forming frames respectively for said plurality of sectors, with logical subchannel numbers and OFDMA symbol numbers used for transmission and reception,

wherein said frames formed respectively for said plurality of sectors are configured such that preambles and pieces of frame control information arranged sequentially from beginnings of said frames do not interfere with each other between said frames.

2. The radio base-station apparatus according to claim 1, further comprising a reference clock source that generates a reference clock for synchronizing said frames formed respectively for said plurality of sectors;

and a delay adder that adds an offset to the beginning of a given one of said frames synchronized on the basis of said reference clock,

wherein said offset is added to the beginning of the given one of said frames such that said preambles and said frame control information pieces arranged sequentially from the beginnings of said frames formed respectively for said plurality of sectors do no overlap on said OFDMA symbol numbers.

3. The radio base-station apparatus according to claim 2, wherein said reference clock source is a GPS receiver that receives a GPS signal from which said reference clock can be extracted.

4. The radio base-station apparatus according to claim 1, further comprising a reference clock source that generates a reference clock for synchronizing said frames formed respectively for said plurality of sectors,

wherein said preambles and said frame control information pieces sequentially arranged from the beginnings of said frames formed respectively for said plurality of sectors are arranged such that respective said preambles are made of different preamble patterns having no correlation among said plurality of sectors and respective said preambles overlap on said OFDMA symbol numbers, and such that respective said frame control information pieces do not overlap on said OFDMA symbol numbers.

5. The radio base-station apparatus according to claim 4, wherein said reference clock source is a GPS receiver that receives a GPS signal from which said reference clock can be extracted.

6. The radio base-station apparatus according to claim 1, further comprising a reference clock source that generates a reference clock for synchronizing said frames formed respectively for said plurality of sectors,

wherein said preambles and said frame control information pieces sequentially arranged from the beginnings of said frames formed respectively for said plurality of sectors are arranged such that respective said preambles are made of different preamble patterns having no correlation among said plurality of sectors and respective said preambles overlap on said OFDMA symbol numbers, and such that respective said frame control information pieces do not overlap on said logical subchannel numbers and respective said frame control information pieces overlap on said OFDMA symbol numbers.

7. The radio base-station apparatus according to claim 6, wherein said reference clock source is a GPS receiver that receives a GPS signal from which said reference clock can be extracted.

8. A radio communications system, wherein, with the radio base-station apparatus according to claim 2, said radio base-station apparatus is connected to a network, and said network is connected to a monitoring control apparatus that performs management, setting, and changing of said preambles and said frame control information pieces arranged in respective said frames formed respectively for said plurality of sectors, and that also performs management, setting, and changing of said offset added to said frame.

9. A radio communications system which comprises a plurality of cells each comprising the radio base-station apparatus according to claim 3, wherein said GPS receivers of said radio base-station apparatuses respectively corresponding to said plurality of cells extract said reference clock from said GPS signal, and said radio base-station apparatuses corresponding to said plurality of cells are synchronized on the basis of said reference clock.

10. A radio communications system which comprises a plurality of cells each comprising the radio base-station apparatus according to claim 5, wherein said GPS receivers of said radio base-station apparatuses respectively corresponding to said plurality of cells extract said reference clock from said GPS signal, and said radio base-station apparatuses corresponding to said plurality of cells are synchronized on the basis of said reference clock.

11. A radio communications system which comprises a plurality of cells each comprising the radio base-station apparatus according to claim 7, wherein said GPS receivers of said radio base-station apparatuses respectively corresponding to said plurality of cells extract said reference clock from said GPS signal, and said radio base-station apparatuses corresponding to said plurality of cells are synchronized on the basis of said reference clock.

12. The radio communications system according to claim 9, wherein said radio base-station apparatuses corresponding to said plurality of cells are connected to a network, and said network is connected to a monitoring control apparatus that performs management, setting, and changing of said preambles and said frame control information pieces arranged in respective said frames formed respectively for said sectors, and that also performs management, setting, and changing of said offsets added to said frames.