Techniques for providing efficient transmit diversity and bandwidth segmentation in a wireless communication system

• US 7,415,288 B1
• Filed: 01/09/2006
• Issued: 08/19/2008
• Est. Priority Date: 01/07/2005
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Wang, Jing, Chion, Mary, Cai, Sean, Hou, Jason, Feng, Dazi
• Primary Examiner(s): Le; Danh C
• Application Number:
  US11/328,832
• Time in Patent Office: 953 Days
• Field of Search: 455/562.1, 455/561, 455/101, 370/334, 375/267
• US Class Current: 455/562.1
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• 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 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Wireless communication techniques for cellular deployment of wireless communication systems with transmitters in each cell to have partially overlapped transmission patterns between two adjacent transmitters. Implementations of the described techniques can provide transmit diversity with intentional partial beam pattern overlays to improve cell sectorization or frequency re-use factor, at the same time, reduce intra-cell and inter-cell interference. Various modulations may be used in the described systems, including FDMA, TDMA, and OFDMA modulation schemes.

Claims

1. A method for cellular wireless communication, comprising:

providing in each cell a set of first group radio transmitters that divide the cell into a set of first group sectors with one first group radio transmitter per first group sector;

providing in each cell a set of second group radio transmitters that divide the cell into a set of second group sectors with one second group radio transmitter per second group sector, wherein the set of second group sectors are equal in number and in size to the set of first group sectors;

arranging the first and the second radio group transmitters in each cell to overlap the first and second group sectors in a manner that the first group sectors are spatially shifted from and spatially interleaved with the set of second group sectors so that each first group sector spatially overlaps with two adjacent second group sectors and vice versa;

assigning a set of sector radio bandwidth segments to the set of first group radio transmitters, respectively, to transmit to the set of first group sectors, respectively, wherein two adjacent first group sectors are assigned with different sector radio bandwidth segments;

assigning the set of sector radio bandwidth segments to the set of second group radio transmitters, respectively, to transmit to the set of second group sectors, respectively, wherein two adjacent second group sectors are assigned with different sector radio bandwidth segments, and a first group sector and a second group sector that are assigned with the same sector radio bandwidth segment are spatially separate from each other without overlap;

further operating each first group radio transmitter to transmit at a sector radio bandwidth segment to provide transmit diversity for a second group sector in the overlapped area of the two sectors; and

further operating each second group radio transmitter to transmit at a sector group radio bandwidth segment to provide transmit diversity for a first group sector in the overlapped area of the two sectors.

2. A method as in claim 1, wherein the set of sector radio bandwidth segments includes groups of subcarriers under an Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) technology.

3. A method as in claim 2, further comprising assigning a portion of subchannel carriers under either OFDM or OFDMA to each sector radio bandwidth segment as a sector frequency band.

4. A method as in claim 1, wherein the set of sector radio bandwidth segments are based on a frequency division of an available frequency bandwidth for the cellular wireless communication.

5. A method as in claim 4, wherein the contiguous frequency division of an available frequency bandwidth is Frequency Division Multiple Access (FDMA).

6. A system as in claim 5, wherein a first group sector and a second group sector that are assigned with the same sector radio bandwidth segment are spatially separate from each other and located at opposing sides of the cell without overlap.

7. A method as in claim 4, further comprising assigning multicarrier transmission on each radio transmitter.

8. A method as in claim 1, wherein the set of sector radio bandwidth segments is according to a time division of an available frequency bandwidth for the cellular wireless communication.

9. A method as in claim 8, wherein the set of sector radio bandwidth segments is according to a Time Division Multiple Access (TDMA) technology.

10. A cellular wireless communication system, comprising:

a plurality of base stations spatially distributed to define radio cells to wirelessly communicate with wireless subscriber stations in each cell,

wherein each base station corresponds to one cell and comprises;

a set of first group radio transmitters that divide the cell into a set of first group sectors with one first group radio transmitter per first group sector;

a set of second group radio transmitters that divide the cell into a set of second group sectors with one second group radio transmitter per second-group-sector, wherein the set of second group sectors are equal in number and in size to the set of first group sectors, and are spatially shifted from and spatially interleaved with the set of first group sectors so that each first group sector spatially overlaps with two adjacent second group sectors and vice versa; and

a transmission circuit to supply a set of sector radio bandwidth segments to the set of first group radio transmitters, respectively, to transmit to the set of first group sectors, respectively, and to supply the set of sector radio bandwidth segments to the set of second group radio transmitters, respectively, to transmit to the set of second group sectors, respectively, in a manner that, two adjacent or overlapped sectors are assigned with different sector radio bandwidth segments and a first group sector and a second group sector that are assigned with the same sector radio bandwidth segment are spatially separate from each other without overlap.

11. A system as in claim 10, further comprising a mechanism in the transmission circuit to cause each of the first and second group radio transmitters to transmit according to a Frequency Transmit Diversity (FTD), Frequency Hoping Diversity Coding (FHDC).

12. A system as in claim 10, wherein the transmission circuit is adapted to operate each first group radio transmitter to transmit at a sector radio bandwidth segment to provide transmit diversity for a second group sector that partially overlaps with a first group sector of the first group radio transmitter in an overlapped region of the first and the second group sectors, and operates each second group radio transmitter to transmit at a sector radio bandwidth segment to provide transmit diversity for a first group sector that partially overlaps with a second group sector of the second group radio transmitter in an overlapped region of the first and second group sectors.

13. A system as in claim 12, further comprising a mechanism in the transmission circuit to cause each of the first and second group radio transmitters to transmit according to a Space Time Transmit Diversity (STTD), Space Time Coding (STC).

14. A system as in claim 12, further comprising a mechanism to provide channel estimation in aiding receiver demodulation of transmit diversity in each region where a first group sector and a second group sector overlap.

15. A system as in claim 12, wherein the transmission circuit of each base station further comprises:

a plurality of sector signal generator circuits coupled to supply transmission signals for both first group and second group radio transmitters, wherein each sector signal generator circuit comprises;

a sector main signal generator to generate a main transmission signal in a sector radio bandwidth segment for a sector assigned with the sector radio bandwidth segment,

a sector diversity encoder to generate a sector diversity transmission signal for the sector assigned with the radio bandwidth segment, and

a signal combiner to combine the sector diversity transmission signal for another sector which generated from the diversity signal generator of the corresponding sector signal generator circuit and the sector main transmission signal into a final transmission signal.

16. A system as in claim 12, wherein the first and second transmitters and the transmission circuit are adopted as a Multiple-Input Multiple-Output (MIMO) system.

17. A system as in claim 16, wherein the MIMO system is an open-loop MIMO.

18. A system as in claim 16, wherein the MIMO system is a closed-loop MIMO.

19. A system as in claim 16, wherein each radio transmitter comprises a directional antenna.

20. A cellular wireless communication system, comprising:

a plurality of base stations spatially distributed to define radio cells to wirelessly communicate with wireless subscriber stations in each cell,

wherein each base station corresponds to one cell and comprises;

a plurality of radio transmitters that are spatially arranged relative to one another to partially overlap a transmission pattern of one radio transmitter with (1) a transmission pattern of a first adjacent radio transmitter on one side of the radio transmitter and (2) a transmission pattern of a second adjacent radio transmitter on the other side of the radio transmitter to form two overlapped regions as two separate sectors of the cell, thus forming a number of sectors of the cell that is equal to a number of the radio transmitters; and

a transmission circuit to supply a set of different radio bandwidth segments to the radio transmitters, wherein two adjacent radio transmitters are assigned to transmit at different radio bandwidth segments, and wherein two radio transmitters that produce two transmission patterns located at opposing sides of the cell without overlap are assigned with the same radio bandwidth segment.

21. A system as in claim 20, wherein the transmission circuit is adapted to operate each radio transmitter to transmit at a radio bandwidth segment assigned to another radio transmitter to provide transmit diversity in each sector.

22. A system as in claim 21, wherein the transmission circuit comprises a plurality of transmitter circuits coupled to supply transmission signals to the radio transmitters, respectively, wherein each transmitter circuit comprises:

a transmitter signal generator to generate a transmission signal in a radio bandwidth segment assigned to a radio transmitter corresponding to the transmitter circuit,

a transmission diversity encoder to generate, from the transmission signal, a main path transmission signal at the assigned radio bandwidth segment for the radio transmitter to transmit and a diversity transmission signal at a different radio bandwidth segment to supply to a different radio transmitter assigned with the different radio bandwidth segment, and

a signal combiner to combine another diversity transmission signal at a second different radio bandwidth segment assigned to a second different radio transmitter and the main path transmission signal into an output transmission signal for the radio transmitter to transmit.

23. A system as in claim 20, wherein different radio bandwidth segments are different frequency bands under a frequency division scheme.

24. A system as in claim 20, wherein different radio bandwidth segments are different segments under a time division scheme.