Flexible wideband architecture for use in radio communications systems

• US 6,205,133 B1
• Filed: 11/25/1996
• Issued: 03/20/2001
• Est. Priority Date: 11/25/1996
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Bexten, Ronald L.
• Primary Examiner(s): Marcelo, Melvin
• Assistant Examiner(s): Nguyen, Phuongchau Ba
• Application Number:
  US08/753,437
• Time in Patent Office: 1,576 Days
• Field of Search: 370/326, 370/328, 370/343, 370/338, 370/366, 370/445, 370/433, 370/434, 370/407, 370/425, 375/219
• US Class Current: 370/343
• CPC Class Codes: H04B 1/0007 wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 88/085 Access point devices with remote components
• CPC Class Codes: H04W 99/00 Subject matter not provided for in other groups of this subclass

Abstract

A wideband digital architecture for use in radio communications systems. In an exemplary embodiment, a central hub station is coupled by high speed digital data transports to multiple distributed radio transceivers. The radio transceivers are designed to perform relatively little signal processing, while the central hub is designed to perform computationally intensive signal processing tasks. By exchanging wideband data between the radio transceivers and the hub, by centralizing key system resources at the hub, and by adaptively allocating the system resources in accordance with actual system usage, the radio architecture of the present invention maximizes overall system capacity, flexibility, and resource usage efficiency while minimizing the overall system cost.

Claims

1. A radio communications system, comprising:

a plurality of distributed radio transceivers, wherein each of said transceivers includes a wideband radio transmitter for transmitting multiple information signals on multiple frequency channeling multiple system users, and wherein each of said transceivers includes a wideband radio receiver for receiving multiple information signals on multiple frequency channels from the multiple system users;

a plurality of high speed data transports, each one of said data transports connected to a corresponding one of said transceivers, for carrying wideband signals containing multiple information signals; and

a hub station, connected to each one of said data transports and exchanging wideband signals with each of one said transceivers, wherein said hub station includes a) a downlink channelizer for coupling information signals received from a mobile switching center to said data transports, b) an uplink channelizer for coupling information signals received at said data transports to the mobile switching center, and c) a resource manager for monitoring system activity and for controlling said downlink channelizer and said uplink channelizer to adaptively allocate and utilize channelizer resources in selecting and processing information signals.

2. The system of claim 1, wherein said system provides radio-communication support for a pico-cell in a cellular radio communications system.

3. The system of claim 1, wherein said system provides radio-communication support for an indoor cell in a cellular radio communications system.

4. The system of claim 1, wherein at least one of said high speed data transports is implemented using a fiber optic link.

5. The system of claim 1, wherein at least one of said high speed data transports is implemented using an ethernet link.

6. A radio transceiver, comprising:

a wideband radio transmitter for simultaneously transmitting multiple information signals on multiple frequency channels to multiple mobile stations in a radio communications system;

a wideband radio receiver for simultaneously receiving multiple information signals on multiple frequency channels from the multiple mobile stations in the system,

a high speed data transport interface for exchanging, through a high speed data transport, wideband signals containing multiple information signals with a hub station in the radio communications system; and

an uplink channelizer for converting wideband frequency-division multiplexed signals received at the transceiver to time-division multiplexed signals which are delivered to the hub station.

7. A radio transceiver, comprising:

a wideband radio transmitter for simultaneously transmitting multiple information signals on multiple frequency channels to multiple mobile stations in a radio communications system;

a wideband radio receiver for simultaneously receiving multiple information signals on multiple frequency channels from the multiple mobile stations in the system,

a high speed data transport interface for exchanging, through a high speed data transport, wideband signals containing multiple information signals with a hub station in the radio communications system; and

a downlink channelizer for converting time-division multiplexed signals received from the hub station to wideband frequency-division multiplexed signals which are transmitted to the mobile stations.

8. A hub station, comprising:

a plurality of high speed data transport interfaces for receiving a plurality of wideband uplink signals, each wideband uplink signal containing multiple uplink information signals, from a plurality of distributed radio transceivers and for transmitting a plurality of wideband downlink signals, each wideband downlink signal containing multiple downlink information signals, to the plurality of distributed radio transceivers;

a communication interface for transmitting a formatted uplink signal containing multiple uplink information signals to a mobile switching center and for receiving a formatted downlink signal containing multiple downlink information signals from the mobile switching center;

an uplink channelizer disposed between said high speed data transport interfaces and said communication interface for processing uplink information signals received from the distributed radio transceivers and for arranging selected uplink information signals to form a formatted uplink signal which is delivered to the mobile switching center;

a downlink channelizer disposed between said communication interface and said high speed data transport interfaces for processing downlink information signals received from the mobile switching center and for arranging selected downlink information signals to form a plurality of wideband downlink signals which are delivered to the distributed radio transceivers; and

a resource manager coupled to said uplink and downlink channelizers for monitoring system activity and for controlling said uplink and downlink channelizers to adaptively allocate and utilize channelizer components in selecting, processing, and arranging the uplink and downlink information signals.

9. The hub station of claim 8, wherein the uplink channelizer comprises:

an uplink channel selector for accepting the wideband uplink signals received at said high speed data transport interfaces and for selectively generating, under control of said resource manager, a plurality of single-channel uplink signals, each single-channel uplink signal corresponding to a selected channel within one of the wideband uplink signals;

a multi-channel demodulator coupled to said uplink channel selector for receiving the single-channel uplink signals and for selectively processing the single-channel uplink signals, under control of said resource manager, to produce a plurality of demodulated uplink signals; and

an uplink time switch coupled to said multi-channel demodulator for arranging the demodulated uplink signals, under control of said resource manager, to form a formatted uplink signal which is delivered to the mobile switching center.

10. The hub station of claim 9, wherein said uplink channel selector includes at least one receive signal strength indicator generating output which is used by said resource manager to monitor activity on channels within the wideband uplink signals received from the distributed radio transceivers.

11. The hub station of claim 9, wherein said uplink channel selector comprises:

a plurality of digital receivers, each of said digital receivers accepting a wideband uplink signal and downconverting a selected channel within the wideband uplink signal to produce a single-channel uplink signal which is delivered to said multi-channel demodulator; and

a cross-point switch coupled to said resource manager for selectively directing wideband uplink signals received from the distributed radio transceivers to inputs of said digital receivers.

12. The hub station of claim 9, wherein said uplink channel selector comprises a plurality of processing circuits, each of said processing circuits including a discrete Fourier transform demultiplexer and a cross-point switch which is coupled to said resource manager, wherein each of said processing circuits receives a wideband uplink signal from a distributed radio transceiver and produces, under control of said resource manager, a plurality of single-channel uplink signals which are delivered to said multi-channel demodulator.

13. The hub station of claim 12, wherein each of said processing circuits further comprises a multiplexer for arranging the plurality of single-channel uplink signals generated by the processing circuit to form a time-division multiplexed signal which is delivered to said multi-channel demodulator.

14. The hub station of claim 9, wherein said multi-channel demodulator comprises:

a plurality of digital signal processors, each of said processors processing at least one of the single-channel uplink signals generated by said uplink channel selector to produce a demodulated uplink signal; and

a cross-point switch coupled to said resource manager for selectively directing the single-channel uplink signals received from said uplink channel selector to inputs of said digital signal processors.

15. The hub station of claim 14, wherein each of said processors processes more than one of the single-channel uplink signals generated by said uplink channel selector to provide channel diversity.

16. The hub station of claim 8, wherein the downlink channelizer comprises:

a downlink time switch for accepting a formatted downlink signal from the mobile switching center and for parsing the formatted downlink signal, under control of said resource manager, to produce a plurality of unmodulated downlink signals;

a multi-channel modulator coupled to said downlink time switch for receiving the unmodulated downlink signals and for selectively processing the unmodulated downlink signals, under control of said resource manager, to create a plurality of single-channel downlink signals; and

a downlink channel selector coupled to said multi-channel modulator for accepting the single-channel downlink signals and for selectively generating, under control of said resource manager, a plurality of wideband downlink signals which are delivered to the distributed radio transceivers.

17. The hub station of claim 16, wherein said downlink channel selector comprises a bank of digital upconverters, each of said upconverters upconverting a single-channel downlink signal to a selected channel within a wideband downlink signal which is delivered to a distributed radio transceiver.

18. The hub station of claim 16, wherein said downlink channel selector comprises a bank of inverse discrete Fourier transform multiplexers, each of said multiplexers translating a plurality of single-channel downlink signals to form a wideband downlink signal which is delivered to a distributed radio transceiver.

19. A method for conducting radio communications in a system including a centralized hub station and a plurality of distributed radio transceivers, comprising the steps of:

using a plurality of high speed data transports to pass wideband frequency division multiplexed signals, each wideband frequency division multiplexed signal including a number of information signals modulated on a number of carrier frequencies, serially between the hub station and the distributed radio transceivers;

continually measuring system activity; and

dynamically allocating, based on said step of measuring, hub station resources in processing and directing the information signals

wherein each of the distributed radio transceivers includes a wideband radio transmitter for transmitting multiple information signals on multiple frequency channels to multiple system users and a wideband radio receiver for receiving multiple information signals on multiple frequency channels from the multiple system users,

wherein the centralized hub station includes a downlink channelizer for coupling information signals received from a mobile switching center to the data transports and an uplink channelizer for coupling information signals received from the data transports to the mobile switching center, and

wherein said step of dynamically allocating hub station resources includes the step of controlling the downlink channelizer and the uplink channelizer in passing information signals between the distributed radio transceivers and the hub station.

20. The method of claim 19,

wherein each of the distributed radio transceivers includes a wideband radio transmitter for transmitting multiple information signals on multiple frequency channels to multiple system users and a wideband radio receiver for receiving multiple information signals on multiple frequency channels from the multiple system users,

wherein the centralized hub station includes a downlink channelizer for coupling information signals received from a mobile switching center to the data transports and an uplink channelizer for coupling information signals received from the data transports to the mobile switching center, and

wherein said step of dynamically allocating hub station resources includes the step of controlling the downlink channelizer and the uplink channelizer in passing information signals between the distributed radio transceivers and the hub station.