Apparatus and method of frame aligning information in a wireless telecommunications system

• US 5,809,093 A
• Filed: 11/16/1995
• Issued: 09/15/1998
• Est. Priority Date: 06/02/1995
• Status: Expired due to Fees

• Current Assignee: Airspan Networks Inc.
• Original Assignee: DSC Communications Corp. (Nokia Corporation)
• Inventors: Cooper, Ian L.
• Primary Examiner(s): VO, DON NGUYEN
• Application Number:
  US08/558,444
• Time in Patent Office: 1,034 Days
• Field of Search: 375/363, 375/365, 375/366, 375/354, 375/368, 375/370, 370/509, 370/510, 370/511, 370/514
• US Class Current: 375/365
• CPC Class Codes: G06F 8/71 Version control security arrangements therefor G06F21/57; Configuration management
• CPC Class Codes: G06F 9/546 Message passing systems or structures, e.g. queues
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/70735 Code identification H04B1/7083 takes precedence
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/70775 Multi-dwell schemes, i.e. multiple accumulation times
• CPC Class Codes: H04B 2201/70706 with means for reducing the peak-to-average power ratio
• CPC Class Codes: H04B 2201/7071 with dynamic control of receiver resources
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 2209/34 Encoding or coding, e.g. Huffman coding or error correction
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 41/08 Configuration management of networks or network elements address allocation H04L61/50
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
• CPC Class Codes: H04L 9/3215 using a plurality of channels network architectures or network communication protocols using different networks H04L63/18
• CPC Class Codes: H04L 9/40 : Network security protocols
• CPC Class Codes: H04Q 11/04 : for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/1305 : Software aspects
• CPC Class Codes: H04Q 2213/13093 : Personal computer, PC
• CPC Class Codes: H04Q 2213/13098 : Mobile subscriber
• CPC Class Codes: H04Q 2213/13109 : Initializing, personal profile
• CPC Class Codes: H04Q 2213/1319 : Amplifier, attenuation circuit, echo suppressor
• CPC Class Codes: H04Q 2213/13196 : Connection circuit/link/trunk/junction, bridge, router, gateway
• CPC Class Codes: H04Q 2213/13199 : Modem, modulation
• CPC Class Codes: H04Q 2213/13202 : Network termination [NT]
• CPC Class Codes: H04Q 2213/13204 : Protocols
• CPC Class Codes: H04Q 2213/13216 : Code signals, frame structure
• CPC Class Codes: H04Q 2213/13292 : Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13296 : Packet switching, X.25, frame relay
• CPC Class Codes: H04Q 2213/13298 : Local loop systems, access network
• CPC Class Codes: H04Q 2213/13299 : Bus
• CPC Class Codes: H04Q 2213/13335 : Simulation, emulation
• CPC Class Codes: H04Q 2213/13376 : Information service, downloading of information, 0800/0900 services
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/52 : using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 76/10 : Connection setup
• CPC Class Codes: H04W 84/14 : WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

A wireless telecommunications system (1) includes a central terminal (10) for transmitting and receiving radio frequency signals to and from a subscriber terminal (20). A downlink communication path is established from a transmitter (200) of the central terminal (10) to a receiver (202) of the subscriber terminal (20). A downlink signal (212) is transmitted from the transmitter (200) to the receiver (202) during setup and operation of the wireless telecommunications system (1) carrying information partitioned into a plurality of frames. The downlink signal (212) includes an overhead channel (224) having a frame alignment signal (232) for each frame of information. The receiver (202) monitors the downlink signal (212) to identify the frame alignment signal (232). The downlink communication path is established when the receiver (202) identifies two successive frame alignment signals (232).

Claims

1. A method of frame aligning information in a telecommunications system, comprising the steps of:

transmitting a downlink signal from a transmitter in a central terminal;

receiving a downlink signal at a receiver in a subscriber terminal;

identifying a beginning of frame position in a data stream of the downlink signal, wherein the beginning of frame position corresponds to an eight bit frame alignment word within the downlink signal;

identifying a successive beginning of frame position in the data stream of the downlink signal;

establishing a downlink communication path from the transmitter in the central terminal to the receiver in the subscriber terminal for receipt of traffic on the downlink signal in response to identifying two successive beginning of frame positions, wherein each beginning of frame position corresponds to a frame alignment word within the downlink signal, wherein the frame alignment word is located in an overhead channel of the downlink signal, wherein the overhead channel is decoded into one of every ten bit positions of the downlink signal, wherein the beginning of frame identifying step includes extracting a first bit position of every ten bits of the downlink signal to identify the frame alignment word, and wherein the beginning of frame identifying step includes extracting a second bit position of every ten bits of the downlink signal to identify the frame alignment word upon an indication that the frame alignment word was not identified during the extraction of the first bit position.

3. The method of claim 1, further comprising the steps of:

monitoring the downlink communication path from the central terminal to the subscriber terminal;

re-identifying two successive beginning of frame positions in response to an interruption in the downlink communication path.

4. The method of claim 3, wherein the re-identifying step includes monitoring a most previous establishment of the downlink communication path to identify a beginning of frame position.

2. A method of frame aligning information in a telecommunications system, comprising the steps of:

transmitting a downlink signal from a transmitter in a central terminal;

receiving a downlink signal at a receiver in a subscriber terminal;

identifying a beginning of frame position in a data stream of the downlink signal, wherein the beginning of frame position corresponds to an eight bit frame alignment word within the downlink signal;

identifying a successive beginning of frame position in the data stream of the downlink signal;

establishing a downlink communication path from the transmitter in the central terminal to the receiver in the subscriber terminal for receipt of traffic on the downlink signal in response to identifying two successive beginning of frame positions;

monitoring the beginning of frame position for each frame in the downlink signal;

re-identifying two successive beginning of frame positions in response to receipt of three successive frames without detecting a beginning of frame position.

5. A system for frame aligning information in a wireless telecommunications system comprising:

a transmitter in a central terminal operable to transmit a downlink signal, the downlink signal including a frame alignment word for each frame of information carried by the downlink signal;

a receiver in a subscriber terminal operable to receive the downlink signal, the receiver operable to identify two successive eight bit frame alignment words in the downlink signal, the receiver operable to establish a downlink communication path from the transmitter in the central terminal to the receiver in the subscriber terminal upon identifying two successive frame alignment words, wherein each frame alignment word is decoded into an overhead channel of the downlink signal, wherein the overhead channel is decoded into one bit of every ten bit positions of the downlink signal, wherein the receiver monitors a first bit position of every ten bits of the downlink signal for identification of successive frame alignment words, wherein the receiver monitors a second bit position of every ten bits of the downlink signal for identification of successive frame alignment words upon an indication that successive frame alignment words were not identified during the monitoring of the first bit position.

6. The system of claim 5, wherein the receiver monitors the downlink communication path from the central terminal to the subscriber terminal, the receiver operable to re-identify two successive frame alignment words in response to an interruption in the downlink communication path, the receiver monitoring a most previous monitored bit position for the frame alignment words to facilitate re-establishment of the downlink communication path.

7. A system for frame aligning information in a wireless telecommunications system comprising:

a transmitter in a central terminal operable to transmit a downlink signal, the downlink signal including a frame alignment word for each frame of information carried by the downlink signal;

a receiver in a subscriber terminal operable to receive the downlink signal, the receiver operable to identify two successive eight bit frame alignment words in the downlink signal, the receiver operable to establish a downlink communication path from the transmitter in the central terminal to the receiver in the subscriber terminal upon identifying two successive frame alignment words, wherein the receiver continuously monitors the downlink signal for frame alignment words, the receiver re-identifying two successive frame alignment words in response to three successive frames without identifying a frame alignment word.

8. A subscriber terminal in a wireless telecommunications system, comprising:

a receiver operable to receive a downlink signal, the downlink signal carrying information partitioned into a plurality of frames, the downlink signal including an eight bit frame alignment word for each of the plurality of frames, the frame alignment word being decoded into an overhead channel of the downlink signal, the overhead channel decoded into one of every ten bit positions of the downlink signal, the receiver operable to identify two successive frame alignment words from the overhead channel of the downlink signal in order to establish a downlink communication path, wherein the receiver monitors a first bit position of every ten bits of the downlink signal to identify frame alignment words, wherein the receiver monitors a second bit position of every ten bits of the downlink signal to identify frame alignment words upon an indication that two successive frame alignment words were not identified during monitoring of the first bit position.

9. A subscriber terminal in a wireless telecommunications system, comprising:

a receiver operable to receive a downlink signal, the downlink signal carrying information partitioned into a plurality of frames, the downlink signal including an eight bit frame alignment word for each of the plurality of frames, the frame alignment word being decoded into an overhead channel of the downlink signal, the overhead channel decoded into one of every ten bit positions of the downlink signal, the receiver operable to identify two successive frame alignment words from the overhead channel of the downlink signal in order to establish a downlink communication path, wherein the receiver continuously monitors the downlink signal for frame alignment words, the receiver re-identifying two successive frame alignment words in response to an interruption of the downlink communication path or upon receiving three successive frames of information without detecting a frame alignment word.