Packet transmissions over cellular radio

• US 6,614,773 B1
• Filed: 12/02/1997
• Issued: 09/02/2003
• Est. Priority Date: 12/02/1997
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Maxemchuk, Nicholas Frank
• Primary Examiner(s): TON, DANG T
• Application Number:
  US08/982,450
• Time in Patent Office: 2,100 Days
• Field of Search: 370/337, 370/330, 370/436, 370/478, 370/341, 370/286, 370/345, 370/521, 370/336, 370/342, 370/280, 370/321, 370/320, 370/332, 370/333, 370/335, 370/346, 370/344, 370/441, 370/442, 370/445, 370/447, 370/449, 370/459, 370/461, 370/462, 340/825.5, 340/825.08, 340/825.01, 375/240, 455/403, 455/509, 455/466, 455/422, 455/562
• US Class Current: 370/337
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

An improved system is achieved in a cellular arrangement where mobile units employ a moveable slot TDM approach to send packets to base stations, and where the base stations use a non-contention approach. When a base station transmits information packets to different mobile units, it merely queues the packets and transmits over a given channel. In a corresponding inbound channel, the mobile units transmit packets to the base station using the MSTDM protocol. The base station also transmits information regarding whether the inbound frequency is occupied by a signal that is being transmitted to the base station, or whether a collision exists. A collision on an inbound frequency occurs when more than one signal is simultaneously transmitted on the inbound frequency. On an additional control channel that is shared by all base stations, the base station sends information in a TDM fashion.

Claims

1. A method for communicating comprising the steps of:

a mobile unit that wishes to transmit information in the form of packets, over a first wireless, shared, inbound channel to a non-mobile base station, determines, based on information derived from a second wireless channel that is other than said first wireless channel and logically distinct from a outbound channel by which said mobile unit receives information packets from said non-mobile base, whether the first wireless channel is busy,

when the first wireless channel is busy, the mobile unit refrains from transmitting,

when the first-wireless channel is not busy, the mobile unit transmits a packet of information,

when said packet is a data packet, the mobile unit also determines, based on information from said second wireless-channel, whether a collision has occurred with a transmission of a packet by some other mobile unit,

when said packet is a data packet and the mobile unit determines the existence of said collision, the mobile unit stops transmitting said packet,

when said packet belongs to a voice source and it is a first packet of said voice source, the mobile unit determines, based on information from said second wireless channel, whether a collision has occurred with a transmission of a packet by some other mobile unit,

when said packet belongs to said voice source and it is a first packet of said voice source, and the mobile unit determines the existence of said collision, the mobile unit stops transmitting said packet, and

when said packet belongs to said voice source and it is other than said first packet of said voice source, the mobile unit transmits the entire packet without determining whether a collision has occurred with a transmission of a packet by some other mobile unit.

2. The method of claim 1 where said mobile unit transmits said data packet in one form of modulation, and transmits packets of said voice source in another form of modulation.

3. The method of claim 2, where said one form of modulation is a suppressed carrier form of modulation, and said another form of modulation is a non-suppressed carrier form of modulation, or said another form of modulation is a suppressed carrier form of modulation, and said one form of modulation is a non-suppressed carrier form of modulation.

4. The method of claim 1 where data packets are shorter than packets from voice sources.

5. A cellular arrangement having mobile units and cells, where each cell covers a roughly circular geographical area by means of a base station at the center of the cell, and where a plurality of cells are arranged to cover a larger geographical area, where each base station comprises:

a receiver,

a transmitter,

means for informing mobile units of simultaneous detection of packets in an inbound channel

apparatus associated with the receiver which detects simultaneous reception over the inbound frequency channel of data packets and voice packets, and

apparatus associated with the transmitter which signals a detection of said simultaneous reception of data packets and voice packets over said collision detection frequency channel.