System and method for flexible coding, modulation, and time slot allocation in a radio telecommunications network

• US 5,701,294 A
• Filed: 10/02/1995
• Issued: 12/23/1997
• Est. Priority Date: 10/02/1995
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sandell, Anders, Ward, Torbjorn
• Primary Examiner(s): NGUYEN, CHAU T
• Application Number:
  US08/537,457
• Time in Patent Office: 813 Days
• Field of Search: 370/79, 370/13, 370/17, 370/95.1, 370/95.3, 370/84, 370/252, 370/321, 370/329, 370/332, 370/333, 370/336, 370/341, 370/465, 370/468, 370/347, 370/337, 370/442, 370/498, 371/5.1, 371/5.5, 455/34.1, 455/62, 455/63, 455/67.4, 455/67.1, 455/54.1, 455/33.2, 375/225, 375/227, 375/377, 375/285, 375/254
• US Class Current: 370/252
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0014 by adapting the source coding
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

A system and method for dynamically adapting the user bit rate of a time division multiple access (TDMA) cellular telecommunication system to achieve optimum voice quality over a broad range of radio channel conditions are disclosed. The system continuously monitors radio channel quality on both the uplink and the downlink, and dynamically adapts the system'"'"'s combination of speech coding, channel coding, modulation, and number of assignable time slots per call to optimize voice quality for the measured conditions. Various combinations of the system'"'"'s speech coding, channel coding, modulation, and assignable time slots are identified as combination types and corresponding cost functions are defined. By identifying and selecting the cost function with the lowest cost for the measured radio channel conditions, the system provides the maximum voice quality achievable within the limits of the system design.

Claims

1. A system for dynamically optimizing voice quality in a digital cellular radio telecommunications network, said network having a plurality of user bit rate components that operate at set bit rates, and said network utilizing a plurality of radio channels to carry calls, said system comprising:

means for monitoring and measuring conditions on each of said radio channels, said means for monitoring and measuring having means for continuously monitoring and measuring said conditions;

means for estimating current radio channel quality for each of said radio channels;

means for changing the bit rates of each of said plurality of user bit rate components;

means for dynamically controlling said means for changing bit rates in order to provide the maximum achievable voice quality for calls on each of said radio channels; and

means for monitoring and measuring cellular network conditions that influence achievable voice quality, wherein said cellular network conditions that influence achievable voice quality include;

mobile station (MS) capability;

cellular network capability; and

tariffs.

2. A system for dynamically optimizing voice quality in a digital cellular radio telecommunications network, said network having a plurality of user bit rate components that operate at set bit rates, and said network utilizing a plurality of radio channels to carry calls, said system comprising:

means for monitoring and measuring conditions on each of said radio channels, said means for monitoring and measuring including;

means for continuously monitoring and measuring conditions on each of said radio channels, said means for continuously monitoring and measuring including;

means for continuously monitoring and measuring bit error rates (BER) and signal strengths (SS);

means for estimating current radio channel quality for each of said radio channels;

means for changing the bit rates of each of said plurality of user bit rate components, said plurality of user bit rate components including a speech encoder, a channel encoder, a modulator, a speech decoder, a channel decoder, and a demodulator, wherein said bit rates are changed by switching between a plurality of combination types, each of said plurality of combination types comprising a defined bit rate for each of said plurality of user bit rate components;

means for dynamically controlling said means for changing bit rates in order to provide the maximum achievable voice quality for calls on each of said radio channels, said means for dynamically controlling said means for changing bit rates including;

means for defining a plurality of cost functions, each of said cost functions corresponding to one of said plurality of combination types; and

means for identifying and selecting a cost function that provides the lowest cost for said measured radio channel condition; and

means for monitoring and measuring cellular network conditions that influence achievable voice quality.

3. The system for dynamically optimizing voice quality in a digital cellular radio telecommunications network of claim 2 wherein said means for defining a plurality of cost functions includes:

means for defining cost as a function of radio channel quality;

means for defining cost as a function of cellular network utilization; and

means for adding said cost as a function of radio channel quality and said cost as a function of cellular network utilization to obtain a total cost function for each of said plurality of combination types.

4. The system for dynamically optimizing voice quality in a digital cellular radio telecommunications network of claim 3 wherein said means for defining a plurality of cost functions includes means for applying tariffs to the total cost function for each of said plurality of combination types, said tariffs adjusting said total cost functions depending on network utilization, radio channel quality, and demand for network resources.

5. A system for dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network, said network having a plurality of user bit rate components that operate at set bit rates, and said network utilizing a plurality of time slots to carry a plurality of calls on each radio channel, said system comprising:

means for monitoring and measuring conditions on each of said radio channels, said means for monitoring and measuring conditions including means for continuously monitoring and measuring said conditions;

means for estimating current radio channel quality for each of said radio channels;

means for changing the bit rates of each of said plurality of user bit rate components;

means for allocating time slots to selected calls;

means for dynamically controlling said means for changing bit rates and said means for allocating time slots in order to provide the maximum achievable voice quality for calls on each of said radio channels; and

means for monitoring and measuring cellular network conditions that influence achievable voice quality, said cellular network conditions that influence achievable voice quality including available time slots, mobile station (MS) capability, cellular network capability, and tariffs.

6. A system for dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network, said network having a plurality of user bit rate components that operate at set bit rates, and said network utilizing a plurality of time slots to carry a plurality of calls on each radio channel, said system comprising:

means for monitoring and measuring conditions on each of said radio channels, said means for monitoring and measuring conditions including;

means for continuously monitoring and measuring conditions on each of said radio channels, said means for continuously monitoring and measuring conditions including;

means for continuously monitoring and measuring bit error rates (BER) and signal strengths (SS);

means for estimating current radio channel quality for each of said radio channels;

means for changing the bit rates of each of said plurality of user bit rate components;

said user bit rate components including a speech encoder, a channel encoder, a modulator, a speech decoder, a channel decoder, and a demodulator;

means for allocating time slots to selected calls;

means for dynamically controlling said means for changing bit rates and said means for allocating time slots in order to provide the maximum achievable voice quality for calls on each of said radio channels, said means for dynamically controlling said means for changing bit rates and said means for allocating additional time slots including;

means for defining a plurality of combination types, each of said plurality of combination types comprising;

a bit rate setting for each of said plurality of user bit rate components; and

an allocation of time slots for each call;

means for defining a plurality of cost functions, each of said cost functions corresponding to one of said plurality of combination types; and

means for identifying and selecting a cost function that provides the lowest cost for said measured radio channel conditions; and

means for monitoring and measuring cellular network conditions that influence achievable voice quality.

7. The system for dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network of claim 6 wherein said means for defining a plurality of cost functions includes:

means for defining cost as a function of radio channel quality;

means for defining cost as a function of cellular network utilization; and

means for adding said cost as a function of radio channel quality and said cost as a function of cellular network utilization to obtain a total cost function for each of said plurality of combination types.

8. The system for dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network of claim 7 wherein said means for defining a plurality of cost functions includes means for applying tariffs to the total cost function for each of said plurality of combination types, said tariffs adjusting said total cost functions depending on network utilization, radio channel quality, and demand for network resources.

9. A method of dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network, said network having a plurality of user bit rate components that operate at independently set bit rates, and said network utilizing a plurality of time slots to carry a plurality of calls on each radio channel, said method comprising the steps of:

monitoring and measuring conditions on each of said radio channels, said monitoring and measuring step including continuously monitoring and measuring said conditions;

estimating current radio channel quality for each of said radio channels;

dynamically changing said bit rates and allocating time slots, thereby providing the maximum achievable voice quality for calls on each of said radio channels; and

monitoring and measuring cellular network conditions that influence achievable voice quality, said step of monitoring and measuring cellular network conditions including monitoring and measuring available time slots, mobile station (MS) capability, cellular network capability, and tariffs.

10. A method of dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network, said network having a plurality of user bit rate components that operate at independently set bit rates, and said network utilizing a plurality of time slots to carry a plurality of calls on each radio channel, said method comprising the steps of:

monitoring and measuring conditions on each of said radio channels, said monitoring and measuring step including;

continuously monitoring and measuring conditions on each of said radio channels, said step of continuously monitoring and measuring including;

continuously monitoring and measuring bit error rates (BER) and signal strengths (SS);

estimating current radio channel quality for each of said radio channels;

dynamically changing said bit rates and allocating time slots, thereby providing the maximum achievable voice quality for calls on each of said radio channels, said step of dynamically changing the bit rates and allocating time slots including the steps of;

changing the bit rates of a speech coder, a channel coder, a modulator, a speech decoder, a channel decoder, and a demodulator;

defining a plurality of combination types, said defining step further comprising;

setting a bit rate for each of said plurality of user bit rate components; and

allocating a number of time slots for each call;

defining a plurality of cost functions, each of said cost functions corresponding to one of said plurality of combination types; and

identifying and selecting a cost function that provides the lowest cost for said measured radio channel conditions; and

monitoring and measuring cellular network conditions that influence achievable voice quality.

11. The method of dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network of claim 10 wherein said step of defining a plurality of cost functions includes:

defining cost as a function of radio channel quality;

defining cost as a function of cellular network utilization; and

adding said cost as a function of radio channel quality and said cost as a function of cellular network utilization to obtain a total cost function for each of said plurality of combination types.

12. The method of dynamically optimizing voice quality in a time division multiple access (TDMA) cellular radio telecommunications network of claim 11 wherein said step of defining a plurality of cost functions includes applying tariffs to the total cost function for each of said plurality of combination types, said tariffs adjusting said total cost functions depending on network utilization, radio channel quality, and demand for network resources.