Collision free access scheduling in cellular TDMA-CDMA networks
First Claim
1. A method for scheduling an access channel in a cellular telephony system, said system based on CDMA techniques wherein individual coding sequences are substantially orthogonal to one another and are respectively assigned to the mobile stations for spread-spectrum modulating a common carrier in uplink, and de-spreading demodulating the downlink carrier, in order to make them distinguishable at the air interface, the system adopting a two step procedure for managing the mobile stations'"'"' network access, comprising the steps of:
- selecting a signature burst from a plurality of orthogonal coding sequences;
transmitting said signature burst from said mobile station to said network, said transmission occurring over a first configured physical channel;
pausing for a select time interval;
after said step of pausing, transmitting an acknowledgement message from said network to said mobile station, said message being transmitted over a second configured physical channel, said second channel being one of directly and indirectly correlated to said first channel;
transmitting to said network from said mobile station an access request message on a third configured physical channel, said third configured channel being one of directly and indirectly correlated to at least one of said second and first channels;
assigning a set of signatures and an acknowledgement message into a cell;
calculating first time intervals at said mobile stations, said first time intervals indicative of when said signature bursts are transmitted;
calculating second time intervals at said mobile stations, said second time intervals indicative of a wait for arrival of said acknowledgement message from said network; and
minimizing collisions in said third configured physical channels between said access request messages sent from other mobiles stations via said first and second calculated time intervals depending on both a duration of said respective access request messages and delays in issuing said request messages.
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Abstract
A collision free access method is disclosed for scheduling the access of mobile stations to cellular network having an air interface built in TDMA-CDMA technique where the access procedure is performed on two steps: in the first the mobile station sends a signature for getting the network acknowledgement and the second step is for transmitting the RACH message and the RACH message can be of variable size. The proposed method allows for a multimode operation of the cellular network where the different modes allow for different RACH message sizes based on the fact that the mobile stations adapt the values of the parameters which control the access procedure based on the parameter values of the RACH message they are requested to send according to the supported mode.
88 Citations
14 Claims
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1. A method for scheduling an access channel in a cellular telephony system, said system based on CDMA techniques wherein individual coding sequences are substantially orthogonal to one another and are respectively assigned to the mobile stations for spread-spectrum modulating a common carrier in uplink, and de-spreading demodulating the downlink carrier, in order to make them distinguishable at the air interface, the system adopting a two step procedure for managing the mobile stations'"'"' network access, comprising the steps of:
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selecting a signature burst from a plurality of orthogonal coding sequences;
transmitting said signature burst from said mobile station to said network, said transmission occurring over a first configured physical channel;
pausing for a select time interval;
after said step of pausing, transmitting an acknowledgement message from said network to said mobile station, said message being transmitted over a second configured physical channel, said second channel being one of directly and indirectly correlated to said first channel;
transmitting to said network from said mobile station an access request message on a third configured physical channel, said third configured channel being one of directly and indirectly correlated to at least one of said second and first channels;
assigning a set of signatures and an acknowledgement message into a cell;
calculating first time intervals at said mobile stations, said first time intervals indicative of when said signature bursts are transmitted;
calculating second time intervals at said mobile stations, said second time intervals indicative of a wait for arrival of said acknowledgement message from said network; and
minimizing collisions in said third configured physical channels between said access request messages sent from other mobiles stations via said first and second calculated time intervals depending on both a duration of said respective access request messages and delays in issuing said request messages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification