Multiplexing data of a plurality of channels

Abstract

A code division multiple access (CDMA) communication device comprises a medium access controller (MAC) configured to receive data from a plurality of channels. Each channel is associated with a priority and an identifier. The MAC is further configured to multiplex the data of the plurality of channels for transmission over a CDMA channel based on the priority.

Claims

1. A wireless communication apparatus comprising: a queue and circuitry configured to produce data for a plurality of channels including at least one common control channel (CCCH), at least one dedicated control channel (DCCH) and at least one dedicated traffic channel (DTCH), wherein each of the plurality of channels is associated with a priority and a dynamically adjusted parameter; and multiplex the data of the plurality of channels based on the priority for transmission over a shared channel, wherein hybrid automatic repeat request (H-ARQ) control information is multiplexed onto the shared channel.

2. The apparatus of claim 1 wherein the dynamically adjusted parameter indicates a size limit of an amount of data for multiplexing for that channel.

3. The apparatus of claim 2 wherein the size limit is based on requirements of the channel and the requirements of the plurality of channels differ.

4. The apparatus of claim 1 wherein the priority and the dynamically adjusted parameter prevents monopolization of the shared channel by one of the plurality of channels.

5. The apparatus of claim 1 wherein the H-ARQ control information is multiplexed regardless of the priority of the plurality of channels.

6. The apparatus of claim 1 wherein the priority is based on whether the data is best effort or not best effort.

7. The apparatus of claim 1 wherein each channel is associated with a dedicated traffic channel (DTCH).

8. A method for use in a wireless communication device comprising: producing data for a plurality of channels, wherein the plurality of channels include at least one common control channel (CCCH), at least one dedicated control channel (DCCH), and at least one dedicated traffic channel (DTCH), wherein each of the plurality of channels is associated with a priority and a dynamically adjusted parameter; and multiplexing the data of the plurality of channels based on the priority for transmission over a shared channel, wherein hybrid automatic repeat request (H-ARQ) control information is multiplexed onto the shared channel.

9. The method of claim 8 wherein the dynamically adjusted parameter indicates a size limit of an amount of data for multiplexing for that channel.

10. The method of claim 9 wherein the size limit is based on requirements of the channel and the requirements of the plurality of channels differ.

11. The method of claim 8 wherein the priority and the dynamically adjusted parameter prevents monopolization of the shared channel by one of the plurality of channels.

12. The method of claim 8 wherein the H-ARQ control information is multiplexed regardless of the priority of the plurality of channels.

13. The method of claim 8 wherein the priority is based on whether the data is best effort or not best effort.

14. The method of claim 8 wherein each channel is associated with a dedicated traffic channel (DTCH).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a simplified illustration of a wireless spread spectrum communication system.

(2) FIG. 2 is an illustration of data flowing into a common or shared channel.

(3) FIG. 3 is an illustration of data flowing into a FACH channel within an RNC.

(4) FIG. 4 is an illustration of a prioritization scheme.

(5) FIG. 5 is a prioritization scheme for use with a FACH channel.

(6) FIG. 6 depicts a reservation mechanism used with a common or shared channel.

(7) FIG. 7 depicts data source windows used with a common or shared channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) Data prioritization 70 is used to reduce data latency in a multiuser channel controller 54 as illustrated in FIG. 4. For a particular common or shared channel, certain data must be transmitted on that channel and is shown in the figure as mandatory 88. Other data is preferably sent on the particular channel but may be rerouted to another channel, such as a dedicated channel. This data is referred to as best effort 90. Since mandatory data 88 is not reroutable, it takes priority over best effort data 90.

(9) The type of the data within a packet, such as control 96, signaling 98 and traffic data 100, is also used for prioritization. To accomplish prioritization of the data type, control 96 and signaling 98 data packets are separated from traffic data packets 100. One approach to separating the packets is to group similar data type packets together prior to reception at the controller 54. Alternately, packets sent by each channel prior to reception by the controller 54 are provided with a flag or identifier indicating the packets' data type.

(10) Since a prolonged delay in the transfer of control 96 or signaling 98 data results in a frozen channel, control 96 and signaling 98 data are given a higher priority than traffic data 100. Additionally, data associated with multiple users, common or shared 92, has a higher priority than data for a single user, dedicated 94. The data prioritization scheme is typically stored in the software of the multiuser channel's controller.

(11) During periods of high congestion, data is rerouted to other channels based on its priority 70. For instance, best effort dedicated traffic data is rerouted and mandatory common control data is not. By rerouting data prior to queuing, retransmissions will not be required. Accordingly, the amount of queued data is reduced resulting in lower data latency. Additionally, since the rerouted data is never queued, the duplication of data as experienced in the prior art is eliminated.

(12) A prioritization scheme 72 for use with a FACH 58 is shown in FIG. 5. Since the DSCH, H-ARQ of the MAC-sh have mandatory shared control data, they have the highest priority, highest. Although the H-ARQ of the MAC-d has mandatory control data, being dedicated it is assigned a slightly lower priority, high. The CCCH and DCCH are used for signaling and have the next level of priority, medium. The lowest level of priority is assigned to the DTCH because it has best effort dedicated traffic data.

(13) To facilitate this prioritization scheme 72 for the FACH 58, modifications to the RNC 36 are required. As shown in FIG. 3, the prior art MAC-d 66 controls the DCCH, DTCH and MAC-d's H-ARQ. As shown in FIG. 5, each of these sources has a different priority. Since this data is multiplexed prior to prioritization at the MAC-d 66, the multiplexer of the MAC-d 66 is moved to the MAC-c 60 to allow prioritization at the MAC-c 60. Alternatively, the MAC-d 66 may send the priority and class (mandatory or best effort), such as by a flag or identifier, of each packet of the multiplexed data for prioritization at the MAC-c 60. The data controlled by the RLC 64 and the MAC-sh 68 have equal priority and accordingly, neither requires modification. Using the stored priority list, the data from the various sources is scheduled for transmission and rerouted during periods of high congestion.

(14) Another technique for reducing the latency of data which may be combined with prioritization is to control the flow of data between the various controllers. As shown in FIG. 6, a scheduling mechanism 74 is used to regulate the data entering the common or shared channel 56. The scheduling mechanism 74 tracks the backlog of data in the controller's queue. If the mechanism 74 recognizes congestion and that the data will not be transmitted in a certain period of time, access to the channel 56 limits the flow of data from the individual data sources. The individual sources will recognize the need to reroute data or to not attempt transmission. Using a flow control mechanism with a FACH, MAC and RLC (Layer 2), the latency of signaling is decreased thus increasing efficiency.

(15) To prevent the monopolization of the common or shared channel 56 by one data source 48-52 variable windows 76-86 may be used as shown in FIG. 7. Each data source 48-52 has a window or multiple windows 76-86 of outstanding data in the queue that it is permitted. The size of the window 76 is based on the requirements of the specific source. The window 76 is dynamically adjusted in response to the availability of the queue. As the availability of the channel increases, the size of the windows increase which increases the number of outstanding packets. Conversely, as the availability decreases, the size of the windows decrease which decreases the number of outstanding packets. As a result of the decreased windows, the data sources either reroute or stop sending packets to the windows.