EP1069798A1

Universal mobile telephone system network with improved rate matching method

Abstract

In a UMTS network in which a single user can transmit or receive a number of services having different transmission power requirements over a single channel, a method of determining for each service the number of bits to be punctured or repeated to provide rate matching by the steps of deriving for each service the Energy per Bit per Noise density EB/NO required to achieve a desired Bit Error Rate; from each EB/MO deriving a value of the Energy per coded Symbol per Noise density ES/NO; and from ES/NO deriving a rate matching factor by which that ES/NO can be matched to the minimum Energy per coded Symbol per Noise density applicable to the channel in which the services are multiplexed. The values of EB/NO are stored in a look up table in the BTS and each mobile; the BSC generates values of semi static rate matching factors and spreading factors for each service and transmits them to the BTS and mobiles so that the mobile can calculate from the received values and the values stored in the look up table the number of bits to be punctured or repeated.

EP1069798A1, drawing sheet 1
Sheet 1 of 22

Term

Term ended

Projected expiry passed 12 July 2019, 7.2 years ago.

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11 claims: 2 independent, 9 dependent

  1. 1
    In a UMTS network in which a plurality of services of a single user having different transmission power requirements are multiplexed in one channel and the technique of rate matching is applied, a method of determining for each service the number of bits to be punctured or repeated characterised by the steps of:- deriving for each service the Energy per Bit per Noise density E B /N O required to achieve a desired Bit Error Rate;for each E B /N O deriving a value of the Energy per coded Symbol per Noise density E S /N O ;and from the E S /N O deriving a rate matching factor by which that E S /N O can be matched to the minimum Energy per coded Symbol per Noise density applicable to said one channel.
  2. 2
    A method according to Claim 1 comprising the initial step of generating for each service a look up table containing the value of E B /N O required for each spreading factor used and for every environment likely to be encountered.
  3. 3
    A method according to Claim 2 in which the look up table is stored in the physical layer of the UMTS.
  4. 5
    A method according to Claim 4 comprising performing the derivations of semi static rate matching factor and spreading factor in the Radio Resource Control of the UMTS;transmitting the values to the physical layer of the UMTS;and in the physical layer performing puncturing or repetition in accordance with the transmitted values and the values in the look up table.
  5. 6
    A method according to Claim 4 or Claim 5 in which the rate matching factor is derived by generating a semi static rate matching factor for each service and multiplying the semi static rate matching factor by a dynamic rate matching factor which is equal for all services to be multiplexed.
  6. 7
    A method according to Claim 6 in which the semi static rate matching factor is normalised by division by the coding gain associated with said factor which gain is limited to greater than - 1 dB.
  7. 8
    A method according to Claim 7 in which the semi static rate matching factor and the spreading factor for each service are derived by estimating an initial spreading factor dependent on the number of bits per frame being greater than the sum of the data rates for all services to be multiplexed;comparing the initial spreading factor with said look up table of values of E S /N O for each service and for all likely environments and levels of coding to determine the appropriate set of E S /N O .
  8. 9
    A method according to Claim 4 or Claim 5 in which the rate matching factor is derived by setting the E S /N O of the Coded Composite Transport Channel equal to the E S /N O of a service times the inverse of the rate matching factor.
  9. 10
    A method according to Claim 4 or Claim 5 in which the rate matching factor is derived by setting the E S /N O of a service equal to the Quality of Service after channel coding of that service times the inverse of the rate matching factor.
  10. 11
    A UMTS comprising a UMTS core network;a plurality of Base Station Controllers;associated with each BSC a plurality of Base Transmission Systems;and associatable with each BTS a plurality of mobiles, characterised by every mobile comprising storage means to store a look up table of the number of bits for rate matching required for each service and environment likely to be encountered for each value of E B /N O ;and each BSC comprising means to transmit to each mobile and to each BTS values of spreading factor and semi static rate matching factor for a combination of services to be multiplexed in one channel to or from that mobile.