WiMAX ACCESS POINT NETWORK WITH BACKHAUL TECHNOLOGY

• US 20080090575A1
• Filed: 01/15/2007
• Published: 04/17/2008
• Est. Priority Date: 07/13/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: DesignArt Networks Limited (Qualcomm, Inc.)
• Inventors: TOUBOUL, ASSAF, BARAK, OZ
• Granted Patent: US 7,620,370 B2
• Time in Patent Office: Days
• US Class Current: 455/444
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/047 using dedicated repeater stations
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/20 between access points

Abstract

A WiMAX network and communication method, the network including a plurality of WiMAX nodes deployed in micro or pico cells for providing access service to a plurality of mobile subscribers, a plurality of these nodes being arranged in a cluster, one of the nodes in each cluster being a feeder node coupled to a core network, the modes in each cluster being couple for multi-hop transmission to the feeder node. According to a preferred embodiment, each node includes a transceiver with associated modem, an antenna arrangement coupled to the modem and arranged for multiple concurrent transmissions, and a MAC controller for controlling the transceiver, modem and antenna arrangement for providing both access and backhaul communication.

Claims

1. A WiMAX network comprising:

a plurality of WiMAX nodes deployed in micro or pico cells for providing access service to a plurality of mobile terminals;

a plurality of said nodes being grouped—

in a cluster;

one of said nodes in each said cluster being a feeder node coupled to a core network;

said nodes in each said cluster being linked in a tree topology—

to said feeder node.

2. The WiMAX network according to claim 1, further comprising a point to point backhaul network permitting communication between said nodes in said cluster.

3. The WiMAX network according to claim 2, wherein said backhaul network includes means for implementing at least one interference mitigation technique to reduce interference during transmissions.

4. The WiMAX network according to claim 1, wherein each said node includes:

a transceiver with associated modem;

an antenna arrangement coupled to said modem and arranged for multiple concurrent transmissions;

a MAC controller for controlling said transceiver, modem and antenna arrangement for providing both access and backhaul communication.

5. The WiMAX network according to claim 4, wherein said transceiver, antenna arrangement and MAC controller provide both access communication and a point to point backhaul network permitting communication between said nodes in said cluster.

6. The WiMAX network according to claim 5, wherein said transceiver is a “

terminal RF-IC”

module.

7. The WiMAX network according to claim 5, wherein said antenna arrangement includes a plurality of directional antennas.

8. The WiMAX network according to claim 5, wherein said antenna arrangement includes a plurality of omni-directional antennas, and said MAC controller includes smart antenna logic for beam-forming using said omni-directional antennas.

9. The WiMAX network according to claim 5, wherein said backhaul network is an in-band, point to point backhaul network managed by said MAC controller.

10. The WiMAX network according to claim 9, wherein said backhaul network includes means in said MAC controller for implementing at least one interference mitigation technique to reduce interference during transmissions.

11. The WiMAX network according to claim 10, wherein said means for implementing includes means for controlling transmitter power in response to link conditions.

12. The WiMAX network according to claim 11, wherein said means for controlling includes means in one node for iteratively adjusting transmitter power in another node to which it is linked, in order to approach a pre-defined target CINR in said one node.

13. The WiMAX network according to claim 12, further comprising means for adjusting transmitter power in a node which is interfering with a plurality of other nodes in said cluster until said interference is reduced.

14. The WiMAX network according to claim 13, wherein said means for adjusting includes:

means in each node for determining interference caused by other nodes in said cluster and providing an output signal corresponding thereto;

means in said feeder for polling said plurality of nodes in said cluster to receive said output signals;

means in said feeder for determining, from said received output signals, which node is causing interference to a plurality of other nodes in said cluster; and

means for instructing said interfering node to reduce transmission power.

15. The WiMAX network according to claim 10, wherein said means for implementing includes means for implementing null steering of transmission beams.

16. The WiMAX network according to claim 10, wherein said means for implementing includes means for encoding each concurrent transmission with a different CDMA code.

17. The WiMAX network according to claim 16, wherein said CDMA code includes a code from a Walsh-Hadamard family of codes.

18. The WiMAX network according to claim 10, wherein said means for implementing includes means utilizing Orthogonal Frequency Division Multiple Access (OFDMA) for sub channel management.

19. The WiMAX network according to claim 18, wherein said means for sub-channel management includes:

means for allocating at least one time and frequency slot from an OFDMA time/frequency map to each concurrent transmission; and

means for mapping each said transmission to its allocated slot.

21. The WiMAX network according to claim 10, wherein said means for implementing includes means for implementing spatial beam coordination.

23. The WiMAX network according to claim 10, wherein said means for implementing includes means for implementing a fractional frequency re-use scheme.

24. The WiMAX network according to claim 23, wherein said means for implementing said scheme includes:

software means for dividing the cluster into at least two tiers of links, according to a number of hops from the feeder; and

software means for enabling concurrent communication over one third of an available frequency band on adjacent links in an outermost of said tiers; and

software means for enabling communication on all of said available frequency band on links within all other said tiers.

25. The WiMAX network according to claim 5, further comprising:

means for creating sectorization of transmission from each said node for₁₃ concurrent transmission in three directions over one third of available bandwidth.

26. The WiMAX network according to claim 25, wherein:

said antenna arrangement includes three directional antennas; and

said means for creating sectorization includes means for mounting said antennas such that each antenna is aimed in a different direction.

27. The WiMAX network according to claim 25, wherein:

said antenna arrangement includes a plurality of omni-directional antennas; and

said means for creating sectorization includes means for implementing beam forming techniques to shape form several beams, each said beam comprising transmissions from a selected group of antennas directed to a selected sector.

28. The WiMAX network according to claim 27, wherein said antenna arrangement includes six omni-directional antennas arranged in a circle.

29. The WiMAX network according to claim 27, wherein said antenna arrangement includes nine omni-directional antennas.

30. The WiMAX network according to claim 27, wherein said antenna arrangement includes twelve omni-directional antennas.

31. The WiMAX network according to claim 27, wherein said antenna arrangement includes six omni-directional antennas arranged in two geographically separated triplets, for communication over three sectors of 120°

each.

32. The WiMAX network according to claim 27, wherein said antenna arrangement includes six omni-directional antennas arranged in two sets of triplets, further comprising means for polarization of electromagnetic fields of said antennas, such that each stream has a different polarization, to enable concurrent transmission of three MIMO streams.

33. The WiMAX network according to claim 5, wherein said backhaul communication is in-band backhaul, said transmission being divided into a plurality of transmission frames, each transmission frame including an access time slot and a backhaul time slot.

34. The WiMAX network according to claim 33, further comprising a frame builder in each node, said frame builder being driven by said MAC controller to insert access bursts into each transmission frame for transmission during an access time slot, and backhaul data into each transmission frame for transmission during a backhaul time slot.

35. The WiMAX network according to claim 34, wherein said MAC controller drives said frame builder to fill each frame with transmission slots of access adjacent transmission slots of backhaul, and reception slots of access adjacent reception slots of backhaul.

36. The WiMAX network according to claim 5, wherein said MAC controller further comprises software means for implementing radio resources reuse, whereby geographically separated backhaul links in a cluster transmit over a same radio frequency range, at a same time, for concurrent backhaul transmissions on a single radio frequency channel, substantially without creating interference.

37. The WiMAX network according to claim 36, wherein:

directional beams are provided from each node;

said feeder includes means for receiving interference measurements from said links and means for centrally managing said cluster in accordance with said interference measurements; and

said nodes are deployed below roof-top level,

38. The WiMAX network according to claim 5, further comprising means for allocating 1, 2 or 3 MIMO (Multiple In/Multiple Out) streams to different antennas in said antenna arrangement for backhaul point to point communication between nodes in a link adaptively, in accordance with link conditions.

39. The WiMAX network according to claim 38, further comprising means for adaptive allocation of modulation and coding in said backhaul communication.

40. The WiMAX network according to claim 5, further comprising means for enabling one node, in backhaul, to communicate concurrently with multiple nodes in a single frequency band using SDMA (Space Division Multiple Access) wherein transmissions are separated by different, spatially separated beam allocations, created by geographic separation in deployment.

20. (canceled)

22. (canceled)

41. A WiMAX network comprising:

a plurality of WiMAX nodes deployed in micro or pico cells for providing access service to a plurality of mobile terminals;

a plurality of said nodes being grouped in a cluster;

one of said nodes in each said cluster being a feeder node coupled to a core network;

said nodes in each said cluster being linked in a tree topology to said feeder node;

each said node comprising;

a housing;

a plurality of omni-directional antennas mounted on said housing;

a plurality of transceivers mounted in said housing, each said transceiver having an associated modem and being coupled to one of said antennas; and

a chip including;

a MAC processor which directs and coordinates operation of all other elements in the node;

a packet processor coupled to an inlet of said MAC processor for providing packets with air interface attributes to said modem;

a routing table in said MAC processor for routing packets passing therethrough;

a burst modulator coupled to said MAC processor for producing symbol bursts from a plurality of packets having at least some common air interface attributes, a burst being produced for each sector over which said node is transmitting;

a symbol builder coupled to said burst modulator for receiving said symbol bursts and building an OFDM symbol according to a number of streams, sectors and antenna technique for transmitting each burst, and mapping each burst'"'"'s symbols to frequency and time slots into an OFDMA time/frequency map;

a MIMO processing and beam forming module coupled to said symbol builder for receiving said mapped OFDMA symbols and processing signals related to multiple input—

multiple output communication; and

a transmitter front-end module coupled to said MIMO processing and beam forming module for transmitting said OFDMA signals via a transceiver and associated antenna arrangement.

42. The WiMAX network according to claim 41, wherein said packet processor includes means for monitoring, counting, and enqueuing all incoming and outgoing data packets according to a set of QoS (Quality of Service) classifiers, and a storage element for storing said enqueued packets until transmission.

43. The WiMAX network according to claim 41, further comprising:

a receiver front end module for receiving OFDMA signals transmitted to it and performing inverse operations of said transmitter front end module;

a multi-antenna synchronization module coupled to said receiver front end module for processing said received OFDMA signals;

a MIMO and beam forming receiver module coupled to said synchronization module for implementing an interference cancellation algorithm between multiple streams received from said antenna arrangement;

a symbol de-builder coupled to said MIMO and beam forming receiver module for de-mapping groups of OFDMA symbols in time and frequency, to a set of bursts (in access), as defined by said MAC processor;

a high speed burst demodulator coupled to said symbol de-builder for processing said bursts to data packets which are sent to said MAC processor for further processing.

44. A method of WiMAX communication comprising:

deploying a plurality of WiMAX nodes in micro or pico cells for providing access service to a plurality of mobile terminals;

grouping a plurality of said nodes in a cluster;

coupling one of said nodes in each said cluster to a core network to serve as a feeder node;

linking said nodes in each said cluster in a tree topology to said feeder node.

45. The method according to claim 44, further comprising providing a point to point backhaul network for communication between said nodes in said cluster.

46. The method according to claim 45, wherein said step of providing a backhaul network includes implementing at least one interference mitigation technique to reduce interference during transmissions.

47. The method according to claim 44, further comprising:

forming each said node from;

a transceiver with associated modem; and

an antenna arrangement coupled to said modem and arranged for multiple concurrent transmissions; and

providing a MAC controller in each node for controlling said transceiver, modem and antenna arrangement for providing both access and backhaul communication.

48. The method according to claim 47, further comprising providing a point to point backhaul network for communication between said nodes in said cluster.

49. The method according to claim 47, wherein said step of forming includes forming said node from a terminal RF-IC module radio transceiver with power amplifier.

50. The method according to claim 48, wherein said step of forming includes forming said node from an antenna arrangement including a plurality of directional antennas.

51. The method according to claim 48, wherein said step of forming includes forming said node from an antenna arrangement including a plurality of omni-directional antennas, and providing said MAC controller with smart antenna logic for beam-forming using said omni-directional antennas.

52. The method according to claim 48, wherein said step of providing a backhaul network includes providing an in-band, point to point backhaul network managed by said MAC controller.

53. The method according to claim 52, further comprising implementing in said MAC controller at least one interference mitigation technique to reduce interference during transmissions.

54. The method according to claim 53, wherein said step of implementing includes controlling transmitter power in response to link conditions.

55. The method according to claim 54, wherein said step of controlling includes iteratively adjusting transmitter power in another node to which one node is linked, in order to approach a pre-defined target CINR in said one node.

56. The method according to claim 55, further comprising adjusting transmitter power in a node which is interfering with a plurality of other nodes in said cluster until said interference is reduced.

57. The method according to claim 56, wherein said step of adjusting includes:

measuring, in each node, interference caused by other nodes in said cluster and providing an output signal corresponding thereto;

polling, in said feeder, said plurality of nodes in a cluster to receive said output signals;

determining, in said feeder, from said received output signals, which node is causing interference to a plurality of other nodes in said cluster and providing an output signal corresponding thereto; and

instructing, by said feeder, said interfering node to reduce power from its transmitter.

58. The method according to claim 53, wherein said step of implementing includes implementing null steering of transmission beams.

59. The method according to claim 53, wherein said step of implementing includes encoding each concurrent transmission with a different CDMA code.

60. The method according to claim 59, wherein said step of encoding includes encoding using a code from a Walsh-Hadamard family of codes.

61. The method according to claim 53, wherein said step of implementing includes utilizing Orthogonal Frequency Division Multiple Access (OFDMA) for sub-channel management.

62. The method according to claim 61, wherein said step of utilizing OFDMA includes:

allocating at least one time and frequency slot from an OFDMA time/frequency map to each concurrent transmission; and

mapping each said transmission to its allocated slot.

64. The method according to claim 53, wherein said step of implementing includes implementing spatial beam coordination.

66. The method according to claim 53, wherein said step of implementing includes implementing fractional frequency re-use.

67. The method according to claim 66, wherein said step of implementing includes:

dividing the cluster into at least two tiers of links, according to number of hops to the feeder;

enabling concurrent communication over one third of an available frequency band on adjacent links in an outermost of said tiers; and

enabling communication on all of said available frequency band on links within all other said tiers.

68. The method according to claim 48, further comprising:

creating sectorization of transmission from each said node for concurrent transmission in three directions over one third of available bandwidth.

69. The method according to claim 68, comprising:

forming said antenna arrangement of three directional antennas; and

said step of creating sectorization includes mounting said antennas such that each antenna is aimed in a different direction.

70. The method according to claim 68, comprising:

forming said antenna arrangement of a plurality of omni-directional antennas; and

said step of creating sectorization includes implementing beam forming techniques to form several beams, each said beam comprising transmissions from a selected group of antennas directed to a selected sector.

71. The method according to claim 70, wherein said step of forming an antenna arrangement includes arranging six omni-directional antennas in a circle.

72. The method according to claim 70, wherein said step of forming an antenna arrangement includes arranging nine omni-directional antennas in a selected configuration.

73. The method according to claim 70, wherein said step of forming an antenna arrangement includes arranging twelve omni-directional antennas in a selected configuration.

74. The method according to claim 70, wherein said step of forming an antenna arrangement includes arranging six omni-directional antennas in two geographically separated triplets, for communication over three sectors of 120°

each.

75. The method according to claim 74, wherein said step of forming an antenna arrangement includes arranging six omni-directional antennas in two sets of triplets, further comprising polarizating electromagnetic fields of said antennas, such that each stream has a different polarization, to enable concurrent communication of three MIMO streams.

76. The method according to claim 48, wherein said step of providing a point to point backhaul network includes providing in-band backhaul, by including an access time slot and a backhaul time slot in each transmission frame.

77. The method according to claim 76, wherein said step of providing a backhaul network includes providing a frame builder in each node, and causing said MAC controller to drive said frame builder to insert access bursts into each transmission frame for transmission during an access time slot, and backhaul data into each transmission frame for transmission during a backhaul time slot.

78. The method according to claim 77, wherein said step of causing said MAC controller to drive said frame builder includes driving said frame builder to fill each frame with transmission slots of access adjacent transmission periods of backhaul, and reception slots of access adjacent reception periods of backhaul.

79. The method according to claim 48, further comprising implementing, said MAC controller, radio resources reuse, whereby geographically separated backhaul links in a cluster transmit over a same radio frequency rang, at a same time, for concurrent backhaul transmissions on a single radio frequency channel.

80. The method according to claim 79, wherein said step of implementing radio resources re-use includes:

geographically separating said backhaul links;

providing directional beams from each node;

receiving, in said feeder, interference measurements from said links; and

centrally managing, in said feeder, the cluster in accordance with said interference measurements; and

deploying said nodes below roof-top level,

81. The method according to claim 48, further comprising adaptively allocating 1, 2 or 3 MIMO (Multiple In/Multiple Out) streams to different antennas in said antenna arrangement for backhaul point to point communication between nodes in a link.

82. The method according to claim 81, further comprising adaptively allocation modulation and coding in said backhaul communication.

83. The method according to claim 48, further comprising enabling one node, in backhaul, to communicate concurrently with multiple nodes in a single frequency band using SDMA (Space Division Multiple Access) wherein transmissions are separated by different, spatially separated beam allocations, created by geographic separation in deployment.

63. (canceled)

65. (canceled)

84. A WiMax access point unit comprising:

one RF transceiver for transmitting and receiving both WiMAX access and WiMAX backhaul communications;

a modem coupled to said transceiver;

a plurality of antennas coupled to said modem; and

one controller for controlling said RF transceiver, said modem and said antennas.

85. The WiMAX access point according to claim 84, further comprising:

a housing adapted and configured to hold said transceiver, said modem and said controller;

said antennas being mounted on said housing; and

a system-on-chip mounted in said housing, said system-on-chip including said controller.