CDMA communication system and method using priority-based SIMA quality of service class

• US 6,421,335 B1
• Filed: 10/26/1998
• Issued: 07/16/2002
• Est. Priority Date: 10/26/1998
• Status: Expired due to Fees

• Current Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Ruutu, Jussi Pekka Olavi, Kilkki, Matti Kalevi
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Pizarro, Ricardo M.
• Application Number:
  US09/178,658
• Time in Patent Office: 1,359 Days
• Field of Search: 370/342, 370/328, 370/335, 370/320, 370/310, 370/230, 370/232, 370/233, 370/235, 370/252, 370/395, 370/468, 370/412, 370/462, 370/428, 370/397, 370/429, 370/422
• US Class Current: 370/342
• CPC Class Codes: H04B 7/264 for data rate control
• CPC Class Codes: H04W 28/22 Negotiating communication rate

Abstract

A system and method for integrating a priority-based quality of service in CDMA communication systems that implement data packet transmission, in order to effectively allocate radio resources. Data packet transfers are selectively allocated over a wireless interface operating under a Code Division Multiple Access (CDMA) protocol. A nominal bit rate is established for each user desiring access to the CDMA interface. A relative packet priority is calculated for each of the data packets based on an actual bit rate at the source of the CDMA interface and the established nominal bit rate. An allowable packet priority is calculated for the CDMA interface based on a signal-to-noise ratio of the CDMA interface, and those of the data packets having a relative packet priority greater than or equal to the allowable packet priority of the CDMA interface are transmitted across the CDMA interface.

Claims

1. A method for selectively allocating data packet transfers over a wireless interface operating under a Code Division Multiple Access (CDMA) protocol, comprising:

establishing a nominal bit rate for each of a plurality of users having access to the CDMA interface;

calculating a relative packet priority for each of a plurality of data packets based on an actual bit rate of a packet source at the CDMA interface and the nominal bit rate established for the corresponding one of the users;

determining an allowable packet priority for the CDMA interface based on a signal-to-noise ratio of the CDMA interface; and

transmitting those of the plurality of data packets having a relative packet priority greater than or equal to the allowable packet priority of the CDMA interface.

2. The method of claim 1, further comprising measuring a rate of bit transmission of the data packet entering the CDMA interface to determine the actual bit rate of the data packet transmission.

3. The method of claim 1, further comprising assigning a priority value representative of the relative packet priority to each of the corresponding data packets at a time of transmission of the data packets.

4. The method of claim 3, further comprising storing the priority value as part of a header in the data packet.

5. The method of claim 1, wherein calculating a relative packet priority comprises:

measuring an actual bit rate of the data packet transmission from the source at the CDMA interface; and

calculating the relative packet priority as a ratio of the actual bit rate to the established nominal bit rate.

6. The method of claim 1, wherein calculating a relative packet priority is performed according to the equation:

$\begin{array}{cc}x=4.5+\frac{\ln <br><br>\left({\mathrm{MBR}}_i/\mathrm{NBR}\right)}{\ln <br><br>\left(2\right)}<br><br><br><br>{\mathrm{PL}}_i=\{\begin{array}{cc}7& \mathrm{if}<br><br>\text{\hspace{1em}<br><br>}<br><br>x\ge <br><br>7\\ \lfloor <br><br>x\rfloor <br><br>& \mathrm{if}<br><br>\text{\hspace{1em}<br><br>}<br><br>0<<br><br>x<<br><br>7\\ 0& \mathrm{if}<br><br>\text{\hspace{1em}<br><br>}<br><br>x\le <br><br>0,\end{array}& \left[1\right]\end{array}$

where, MBR_i represents the actual bit rate of the i;

th data packet transmitted over the CDMA interface, NBR represents the established nominal bit rate, [x] represents an integer portion of x, and PL_i represents the relative priority level of the i;

th data packet transmitted over the CDMA interface.

7. The method of claim 1, wherein the nominal bit rate established with respect to a particular user is proportional to a quality of service cost payable by the user.

8. The method of claim 1, wherein determining an allowable packet priority comprises:

determining a number of users occupying the CDMA interface;

determining a maximum number of users allowed on the CDMA interface such that a predetermined signal-to-noise ratio is not exceeded;

calculating a calculated current load condition on the CDMA interface based on a ratio of the number of users occupying the CDMA interface and the maximum number of users allowed on the CDMA inter ace;

partitioning a range of possible load conditions into a plurality of allowable priority levels; and

assigning an allowable priority level corresponding to the calculated current load condition as a current allowable priority level for the CDMA interface.

9. The method of claim 8, wherein partitioning the range of possible load conditions comprises linearly apportioning the range of possible load conditions into the plurality of allowable priority levels.

10. The method of claim 8, further comprising comparing the relative packet priority to the current allowable packet priority to determine which data packets may be transmitted in accordance with the predetermined signal-to-noise ratio.

11. The method of claim 10, further comprising discarding the data packets having a relative packet priority less than the allowable packet priority of the CDMA interface.

12. The method of claim 10, further comprising suspending transmission of the data packets having a relative packet priority less than the allowable packet priority of the CDMA interface.

13. The method of claim 12, wherein suspending transmission of the data packets comprises disallowing transmission of the data packets for a predetermined time period.

14. The method of claim 13, further comprising repeatedly determining the allowable packet priority for the CDMA interface upon a lapse of the predetermined time period, and transmitting the data packets if the relative packet priority reaches or exceeds the allowable packet priority of the CDMA interface.

15. A method for selectively allocating data packet transmission over a wireless interface implementing a Code Division Multiple Access (CDMA) protocol, for data packet transmission from a mobile communication unit (MCU) to a trunking network, the method comprising:

transmitting a transmit request signal from the MCU to the trunking network via a signalling channel;

providing a request response from the trucking network to the MCU indicative of whether the trunking network permits the data packet transmission, comprising;

establishing a nominal bit rate for each of a plurality of users having access to the CDMA interface;

calculating, at the trunking network , a relative packet priority for each of the data packets based on an actual bit rate at a source at the CDMA interface and the nominal bit rate established for the corresponding one of the plurality of users;

calculating, at the trunking network, a current allowable packet priority for the CDMA interface based on a signal-to-noise ratio of the CDMA interface;

comparing, at the trunking network, the relative packet priority for each of the data packets to the current allowable packet priority of the CDMA interface; and

setting the request response to indicate whether the data packet has a sufficiently high relative packet priority to gain access to the CDMA interface; and

receiving the request response from the trunking network at the MCU, and transmitting the data packets to the trunking network if the request response indicates that the relative packet priority is sufficiently high to gain access to the CDMA interface.

16. The method of claim 15, wherein transmitting a request signal further comprises transmitting a length of the data packet to be transmitted.

17. The method of claim 16, wherein calculating the relative packet priority comprises a step for performing a calculation of the actual bit rate.

18. The method of claim 15, wherein calculating a current allowable packet priority for the CDMA interface comprises:

determining a number of users occupying the CDMA interface;

determining a maximum number of users allowed on the CDMA interface such that a predetermined signal-to-noise ratio is not exceeded;

calculating a current load condition on the CDMA interface based on a ratio of the number of users occupying the CDMA inter ace and the maximum number of users allowed on the CDMA interface;

partitioning a range of possible load conditions into a plurality of allowable priority levels; and

assigning one of the plurality of allowable priority levels corresponding to the calculated current load condition as a current allowable priority level for the CDMA interface.

19. The method of claim 18, further comprising comparing the relative packet priority to the current allowable packet priority to determine which data packets may be transmitted.

20. The method of claim 19, further comprising:

suspending transmission of the data packets having a relative packet priority less than the current allowable packet priority of the CDMA interface for a predetermined time period;

repeatedly determining the current allowable packet priority for the CDMA interface upon expiration of the predetermined time period; and

transmitting the data packets if the relative packet priority reaches or exceeds the current allowable packet priority of the CDMA interface.

21. A method for selectively allocating data packet transmission over a wireless interface implementing a Code Division Multiple Access (CDMA) protocol, for data packet transmission from a trunking network to a mobile communication unit (MCU), the method comprising:

establishing a nominal bit rate for each o a plurality of users having access to the CDMA interface;

calculating, at the trunking network, a relative packet priority for each of the data packets based on an actual bit rate of a source at the CDMA interface and the nominal bit rate established for the corresponding one of the plurality of users;

calculating, at the trunking network, a cur rent allowable packet priority for the CDMA interface based on a signal-to-noise ratio of the CDMA interface;

comparing, at the trunking network, the relative packet priority for each of the data packets to the current allowable packet priority of the CDMA interface; and

transmitting the data packets from the trunking network to the MCU if the relative packet priority of the data packets is equal to or greater than the current allowable packet priority of the CDMA interface.

22. The method of claim 21, wherein calculating the relative packet priority comprises a step for performing a calculation of the actual bit rate.

23. The method of claim 21, wherein calculating a current allowable packet priority for the CDMA interface comprises:

determining a number of users occupying the CDMA interface;

determining a maximum number of users allowed on the CDMA interface such that a predetermined signal-to-noise ratio is not exceeded;

calculating a current load condition on the CDMA interface based on a ratio of the number of users occupying the CDMA interace and the maximum number of users allowed on the CDMA interface;

partitioning a range of possible load conditions into a plurality of allowable priority levels; and

assigning one of the plurality of allowable priority levels corresponding to the calculated current load condition as the current allowable priority level for the CDMA interface.

24. The method of claim 21, further comprising:

suspending transmission of the data packets having a relative packet priority less than the current allowable packet priority of the CDMA interface for a predetermined time period;

repeatedly determining the current allowable packet priority for the CDMA interface upon expiration of the predetermined time period; and

transmitting the data packets if the relative packet priority reaches or exceeds the current allowable packet priority of the CDMA interface.

25. The method of claim 21, further comprising discarding the data packets having a relative packet priority less than the current allowable packet priority of the CDMA interface.

26. A method for selectively allocating data packet transmission over a wireless interface implementing a Code Division Multiple Access (CDMA) protocol, for data packet transmission from a mobile communication unit (MCU) to a trunking network, the method comprising:

establishing a nominal bit rate for each of a plurality of users having access to the CDMA interface;

calculating, at the MCU, a relative packet priority for each of the data packets based on an actual bit rate of a source at the CDMA interface and the nominal bit rate established for the corresponding one of the users;

calculating, at the trunking network, a current allowable packet priority for the CDMA interface based on a signal-to-noise ratio of the CDMA interface;

transmitting the current allowable packet priority from the trunking network to the MCU via a signalling channel;

comparing, at the MCU, the relative packet priority for each of the data packets to the current allowable packet priority of the CDMA interface; and

transmitting the data packets from the MCU to the trunking network if the relative packet priority is equal to or greater than the current allowable packet priority at the CDMA interface.

27. The method of claim 26, wherein calculating a current allowable packet priority for the CDMA interface comprises:

determining a number of users occupying the CDMA interface;

determining a maximum number of users allowed on the CDMA interface such that a predetermined signal-to-noise ratio is not exceeded;

calculating a current load condition on the CDMA interface based on a ratio of the number of users occupying the CDMA interface and the maximum number of users allowed on the CDMA interface;

partitioning a range of possible load conditions into a plurality of allowable priority levels; and

assigning one of the plurality of allowable priority level corresponding to the calculated current load condition as the current allowable priority level for the CDMA interface.

28. The method of claim 26, further comprising:

suspending transmission of the data packets having a relative packet priority less than the current allowable packet priority of the CDMA interface for a predetermined time period;

repeatedly determining the current allowable packet priority for the CDMA interface upon expiration of the predetermined time period; and

transmitting the data packets if the relative packet priority reaches or exceeds the current allowable packet priority of the CDMA interface.

29. A system for selectively allocating data packet transfers over a wireless interface operating under a Code Division Multiple Access (CDMA) protocol, for data packet transmission between one or more mobile communication units (MCU) and a trunking network, the system comprising:

a memory to store a nominal bit rate indicator assigned to each potential connection of the CDMA interface;

a bit rate measurement unit to receive a data packet ready for transmission via the CDMA interface and to measure the bit rate at which the data packet will be transmitted;

a packet priority level calculation unit coupled to receive the measured bit rate and the nominal bit rate indicator, and to calculate a packet priority level for the data packet in response thereto;

a comparator coupled to receive the pack t priority level, and to receive an allowable packet priority level corresponding to the packet priority level required to access the CDMA interface, and to output an enable signal indicative of whether or not the packet priority level is greater than the allowable packet priority level; and

an output register to enable transmission of the data packet when the enable signal indicates that the packet priority level is greater than the allowable packet priority level.

30. The system as in claim 29, further comprising:

a timer circuit coupled to the comparator to receive the enable signal, and to effect a predetermined time delay when the enable signal indicates that the packet priority level is not greater than the allowable packet priority level; and

an input enable circuit coupled to the timer allow input of a current state of the allowable packet priority level, and coupled to the comparator to allow further comparisons of the packet priority level of the data packet and the allowable packet priority level.

31. The system as in claim 29, further comprising:

a memory to store a number N of users occupying the CDMA interface, and to store a maximum number N_max of users allowed on the CDMA interface such that a predetermined signal-to-noise ratio is not exceeded; and

a load calculation unit coupled to receive N and N_max and calculate a current load condition based on a ratio of N and N_max, and to convert the load condition into the allowable packet priority level.

32. The system as in claim 31, wherein the bit rate measurement unit, the packet priority level calculation unit, and the comparator are implemented in the MCU.

33. The system as in claim 31, wherein the bit rate measurement unit, the packet priority level calculation unit, and the comparator are implemented in the trunking network.

34. The system as in claim 33, further comprising a transceiver in each of the MCU and the trunking network, wherein the transceiver in the MCU transmits a request signal to the trunking network via a signalling channel, the transceiver in the trunking network receives the request signal and transmits a request response to the MCU indicative of whether the packet priority level of the data packet is greater than the allowable packet priority level, and the transceiver in the MCU receives and routes the request response to the output register to enable transmission of the data packet when the request response indicates that the packet priority level is greater than the allowable packet priority level.