Method of and a radio transmission system and radio access equipment for cellular wireless radio transmission

• US 9,628,232 B2
• Filed: 04/07/2008
• Issued: 04/18/2017
• Est. Priority Date: 04/07/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sahlin, Henrik, Lindgren, Ulf, Zangi, Kambiz
• Primary Examiner(s): Weidner, Timothy J
• Application Number:
  US12/936,301
• Publication Number:
  US 20110026626A1
• Time in Patent Office: 3,298 Days
• Field of Search: 370343, 370344, 370480, 370481, 370482, 370229, 370231, 370232, 370235, 370431, 370432, 370437
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 88/085 Access point devices with remote components
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

Radio transmission in an Orthogonal Frequency Division Multiplex, OFDM, based cellular wireless radio transmission system, wherein radio access equipment of the system connects to multiple geographically spread radio antennas of a Distributed Antenna System, DAS, for transmitting to and receiving radio signals from user equipment. Transmit timings for radio transmission between the user equipment and the antennas of the DAS are established. The radio transmission is scheduled based on the established transmit timings.

Claims

1. A method of radio transmission in an Orthogonal Frequency Division Multiplex (OFDM) based cellular wireless radio transmission system, wherein radio access equipment of said OFDM based cellular wireless radio transmission system connects to multiple geographically spread radio antennas of a Distributed Antenna System (DAS) for transmitting and receiving radio signals to and from user equipment arranged for operating in said radio transmission system, the method comprising the steps of:

establishing transmit timings for radio transmission between said user equipment and said radio antennas of said DAS, said transmit timings being construed as any information provided or measured from which data relevant to absolute propagation times of radio signals between said user equipment and said radio antennas of said DAS can be established, and

scheduling said radio transmission based on said established transmit timings, wherein said scheduling comprises selecting at least one radio antenna of said DAS for transmitting and receiving radio signals to and from said user equipment, and wherein each selected radio antenna of said DAS transmits and receives radio signals to and from said user equipment with equal transmit timings if more than one radio antenna for said DAS is selected.

2. The method according to claim 1, wherein said scheduling comprises selecting a plurality of radio antennas of said DAS for transmitting and receiving radio signals to and from said user equipment, wherein adjust timings are calculated from said established transmit timings and a system timing, and each selected radio antenna of said DAS transmits to said user equipment and receives radio signals from said user equipment with equal adjust timings.

3. The method according to claim 1, wherein said scheduling comprises selecting radio carrier frequency allocation at said radio access equipment for transmitting and receiving radio signals to and from different user equipment.

4. The method according to claim 3, wherein adjacent radio carrier frequencies are allocated to different user equipment having equal transmit timings.

5. The method according to claim 3, wherein adjust timings are calculated from said established transmit timings and a system timing, and wherein adjacent carrier frequencies are allocated to said different user equipment having equal adjust timings.

6. The method according to claim 3, wherein said selected radio carrier frequency allocation comprises sub-carrier frequency allocation.

7. The method according to claim 1, wherein said transmit timings are established using:

uplink signal timing received at said radio access equipment,

time differences of downlink radio signals received at said user equipment,

positioning information derived from a geographic positioning system, or

a geographic position of said user equipment and geographic positions of said radio antennas of said DAS.

8. Radio access equipment, comprising a signal processing unit and a radio transceiver unit arranged for radio transmission in an Orthogonal Frequency Division Multiplex (OFDM) based cellular wireless radio transmission system, for transmitting and receiving radio signals to and from user equipment arranged for operating in said radio transmission system by multiple geographically spread radio antennas of a Distributed Antenna System (DAS) the radio access equipment comprising:

a transmit timing unit, arranged for establishing transmit timings of radio transmission between said user equipment and said radio access equipment, said transmit timings being construed as any information provided or measured from which data relevant to absolute propagation times of radio signals between said user equipment and said radio antennas of said DAS can be established, and

a scheduling unit for scheduling said radio transmission based on said established transmit timings, wherein said scheduling unit selects at least one radio antenna of said DAS for transmitting and receiving radio signals to and from said user equipment, and for operating each selected radio antenna of said DAS for transmitting and receiving radio signals to and from said user equipment with equal transmit timings if a plurality of antennas of said DAS is selected.

9. Radio access equipment according to claim 8, wherein said transmit timing unit calculates adjust timings from said established transmit timings and a system timing, and for operating a plurality of selected radio antennas of said DAS for transmitting and receiving radio signals to and from said user equipment with equal adjust timings.

10. Radio access equipment according to claim 8, wherein said scheduling unit performs selective radio carrier frequency allocation for transmitting and receiving radio signals to and from different user equipment.

11. Radio access equipment according to claim 10, wherein said scheduling unit allocates adjacent radio carrier frequencies to different user equipment which, in operation, having equal transmit timings.

12. Radio access equipment according to claim 10, wherein said transmit timing unit calculates adjust timings from said established transmit timings and a system timing, and wherein said scheduling unit is arranged for allocating adjacent carrier frequencies to said different user equipment having equal adjust timings.

13. Radio access equipment according to claim 10, wherein said transmit timing unit establishes said transmit timings using:

uplink signal timing received at said radio access equipment,

time differences of downlink radio signals received at said user equipment,

positioning Information derived from a geographic positioning system, and

a geographic position of said user equipment and geographic positions of said radio antennas of said DAS.