Patent Application
20080019310
The exemplary embodiments of this invention relate generally to wireless communications systems, methods, devices and computer program products and, more specifically, relate to GERAN GPRS and (E)GPRS capable systems, methods, devices and computer program products.
The following abbreviations are herewith defined:
3GPP third generation partnership project
ACK acknowledgement
AGCH access grant channel
BCCH broadcast control channel
BLER block error rate
BSN block sequence number
BSS base station system
EDGE enhanced data rates for global evolution
(E)GPRS enhanced GPRS
FACCH fast associated control channel
GERAN GSM/EDGE radio access network
GMMRR GMPRS mobility management radio resource
GMPRS geo-mobile packet radio service
GPRS general packet radio services
GRR GPRS radio resource
GSM global system for mobile communications
LLC link layer control
MAC medium access control
MM mobility management
MS mobile station
NACK negative acknowledgement
PACCH packet associated control channel
PAGCH packet access grant channel
PBCCH packet broadcast control channel
PCCCH packet common control channel
PCH paging channel
PD protocol discriminator
PDCH packet data channel
PDTCH packet data traffic channel
PDU protocol data unit
PPCH packet paging channel
PRACH packet random access channel
RACH random access channel
RLC radio link control
RR radio resource
SACCH slow associated control channel
SAP service access point
SAPI service access point identifier
SDCCH stand-alone dedicated control channel
TBF temporary block flow
TTI transmission timing interval
USF uplink state flag
VoIP voice over internet protocol
Reference with regard to the subject matter discussed herein may generally be made to the following publications:
3GPP TS 44.060, V7.4.0, “3rd Generation Partnership Project; Technical Specification Group GSM/EDGE Radio Access Network; General Packet Radio Service (GPRS); Mobile Station (MS)-Base Station System (BSS) interface; Radio Link Control/Medium Access Control (RLC/MAC) protocol (Release 7),” May 2006;
3GPP TSG GERAN2#29bis Tdoc G2-060184, 5.3.3.2, “A performance evaluation of short ACK/NACK reports in varying traffic scenarios,” Ericsson, Sophia Antipolis, France, May 22-24, 2006;
3GPP TSG GERAN2#29bis Tdoc G2-060185, 5.3.3.2, “Latency enhancements-System concept (working assumptions),” Ericsson, Siemens, Sophia Antipolis, France, May 22-24, 2006;
3GPP TSG GERAN2#29bis Tdoc G2-060186, “GERAN Evolution—Summary of Application Gains with RTTI and Shorter RRBP,” Ericsson, Sophia Antipolis, France, May 22-26, 2006;
3GPP TSG GERAN2#29bis Tdoc G2-060203, “RTTI and Fast Ack/Nack reporting,” Siemens, Sophia Antipolis, France, May 22-24, 2006; and
3GPP TSG GERAN2#29bis Tdoc G2-060214, Agenda Item 5.3.7, “Support of VoIP in GERAN A/Gb mode,” Nokia, Alcatel, Sophia Antipolis, France, May 22-26, 2006.
The link level performance of (E)GPRS when using the RLC unacknowledged mode is recognized as one limiting factor for providing packet-switched conversational services, such as VoIP, over (E)GPRS. While the RLC unacknowledged mode allows for meeting the stringent delay requirements inherent in the operation of such services, the BLER performance of the RLC unacknowledged mode is low, which tends to restrict its use to those areas having good cellular coverage.
Conversely, the RLC acknowledged mode allows for increasing the link-level performance of (E)GPRS since it allows re-transmissions of incorrectly received RLC/MAC blocks. While the use of re-transmissions increases the probability of correctly receiving RLC/MAC blocks, their use relies on the receipt of acknowledgment (ACK/NACK) messages from the receiver. However, relying on acknowledgment signaling, as currently defined, introduces delays that are generally prohibitive for delay-sensitive traffic. This is true at least for the reason that a RLC/MAC block is re-transmitted by the RLC transmitter if negatively acknowledged (NACKed) by the receiver until it is positively acknowledged (ACKed) by the receiver. Note that the RLC/MAC block structure is defined in Section 10 of 3GPP TS 44.060.
The preemptive re-transmission of a RLC/MAC block is currently possible in (E)GPRS in two cases: a) if there is no new block to transmit and for blocks of which the acknowledgment status is pending; and b) for the last block (see 3GPP TS 44.060 §§9.1.3.2 and 9.3.3.5).
This being the case, a problem is presented if one wishes to employ the preemptive re-transmissions of RLC/MAC blocks when implementing a delay-sensitive service such as, but not limited to, VoIP.
In an exemplary aspect of the invention, a method includes: determining whether at least one criterion is fulfilled; transmitting a data block to a receiver; and in response to determining that the at least one criterion is met, preemptively re-transmitting the data block to the receiver.
In another exemplary aspect of the invention, a computer program product includes program instructions embodied on a tangible computer-readable medium. Execution of the program instructions results in operations including: determining whether at least one criterion is fulfilled; transmitting a data block to a receiver; and in response to determining that the at least one criterion is met, preemptively re-transmitting the data block to the receiver.
In a further exemplary aspect of the invention, an electronic device includes: a data processor configured to determine whether at least one criterion is fulfilled; and a transmitter coupled to the data processor and configured to transmit a data block to a receiver of another electronic device, wherein the transmitter is further configured, in response to the data processor determining that the at least one criterion is met, to preemptively re-transmit the data block to the receiver of the other electronic device.
In another exemplary aspect of the invention, an electronic device includes: processing means for determining whether at least one criterion is fulfilled; first transmission means for transmitting a data block to a receiver of another electronic device; and second transmission means for preemptively re-transmitting the data block to the receiver of the other electronic device in response to the processing means determining that the at least one criterion is met.
The foregoing and other aspects of embodiments of this invention are made more evident in the following Detailed Description, when read in conjunction with the attached Drawing Figures, wherein:
As will be described below, the exemplary embodiments of this invention resolve the foregoing and other problems by combining and exploiting the benefits inherent in both the low delay of RLC unacknowledged mode and the enhanced link level performance of the RLC acknowledged mode.
Reference is made first to
The MS 10 may be assumed to include and implement a protocol stack 1E, and the BSS 12 may be assumed to include and implement a protocol stack 12E. Reference can be made to
Reference can be made to
The RR sublayer 32 communicates with the MM sublayer 36 via a RR-SAP 46 and a GMMRR-SAP 48. The RR sublayer 32 communicates with the LLC sublayer 38 via a GRR-SAP 50. The RR sublayer 32 communicates with the Physical Link layer 42 via a PDCH 52. The RR sublayer 32 communicates with the Data Link layer 40 via a SAPI-0 54 and a SAPI-3 56. The SAPI-0 54 includes a BCCH, RACH, AGCH, PCH, SDCCH, SACCH and FACCH. The SAPI-3 56 includes a SDCCH and SACCH. The Data Link layer 40 communicates with the Physical Link layer 42 via data paths 58. Note that the RR sublayer 32 itself includes a PD 60, RR management functions 62 and the RLC/MAC functions 34.
In general, the various embodiments of the MS 10 can include, but are not limited to, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions.
The exemplary embodiments of this invention may be implemented by computer software executable by the DP 10A of the MS 10 and the other DPs, or by hardware, or by a combination of software and hardware. The exemplary embodiments of this invention may also be implemented utilizing one or more integrated circuits.
The MEMs 10B, 12B and 14B may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. The DPs 10A, 12A and 14A may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.
The use of the exemplary embodiments of this invention overcome the limitations discussed previously by allowing the transmitter, at any time, to preemptively re-transmit RLC/MAC blocks without necessarily relying on any acknowledgment information from the receiver. This increases the number of correctly received RLC/MAC blocks as compared to the RLC unacknowledged mode, while also considerably decreasing the delay inherent in the use of the RLC acknowledged mode.
The exemplary embodiments of this invention enable the transmitter to immediately re-transmit a RLC/MAC block, for example, immediately after (consecutively to) an initial transmission of that block (or a re-transmission thereof), or “in parallel” with it, as illustrated in
In accordance with the exemplary embodiments of this invention, there is allowed at least one preemptive re-transmission at a time for a given RLC/MAC block. Note that more than one re-transmission may be made if desired.
As noted above, preemptively re-transmitting a RLC/MAC block is currently possible in (E)GPRS in only the cases where there is no new block to transmit and for blocks of which the acknowledgment status is pending, and for only the very last block.
Parallel Preemptive Re-Transmission
The use of parallel re-transmission enables maintaining the transmission time of a RLC/MAC block and its pre-emptive re-transmission within one TTI. Considering a given radio resource pool being used for a RLC/MAC block within a TTI, the parallel re-transmission approach requires a second radio resource pool within the same TTI, as shown in
Consecutive Pre-Emptive Re-Transmission
Consecutive re-transmission implies transmitting a RLC/MAC block, and its corresponding preemptive re-transmission, within two TTIs, while using a single radio resource pool per TTI.
Criteria for Pre-Emptive Re-Transmission
A number of criteria may be used for determining when to transmit an anytime preemptive re-transmission. These criteria may include, but are not limited to, the estimated link quality, the content and/or the priority of the RLC/MAC block (if known).
Combination of Anytime Preemptive Re-Transmission with Existing RLC Modes
The anytime preemptive re-transmission in accordance with the exemplary embodiments of this invention is inherently combinable with all current RLC modes with but minor modifications: RLC unacknowledged mode, RLC acknowledged mode and RLC non-persistent mode (see 3GPP TS 44.060) so as to, for example, considerably improve the link performance of the RLC unacknowledged mode and the RLC non-persistent mode, as well as to reduce the delays of the RLC acknowledged mode.
It should be noted that the use of the exemplary embodiments may be made by the MS 10 for preemptively re-transmitting a RLC/MAC block to the BSS 12, and by the BSS 12 for preemptively re-transmitting a RLC/MAC block to the MS 10. Note that the original and re-transmitted RLC/MAC blocks each carry the same BSN (per 3GPP TS 44.060 §10.4.12).
Note that some signaling may be used to enable preemptive re-transmission. This signaling could be provided, for example, by the network to the MS at TBF assignment.
Further, no new signaling is needed to allocate the additional resources, as existing signaling can be employed for this purpose. For example, if the network desires to make use of parallel preemptive re-transmission, the network ensures that sufficient resources are assigned to make this possible (e.g., at TBF assignment). The network may assign, for example, two timeslots for a TBF but dynamically allocate the two timeslots to that TBF. That is, the network may determine for a given block period to use the two timeslots, or to only use one of them. For example, if the network assigns a downlink TBF on two timeslots, this implies that the MS 10 should monitor the two assigned timeslots for receiving RLC/MAC blocks for that TBF. However, the network does not have to use both of the assigned timeslots at any given time, and it may dynamically allocate a block period to that mobile station on any one, or both, of the assigned timeslots. For an uplink TBF, the network uses the USF in the downlink to dynamically indicate which timeslots the MS should use at a given time in the uplink.
Based on the foregoing it should be apparent that the exemplary embodiments of this invention provide a method, apparatus, devices (including integrated circuit embodiments) and computer program product(s) to send a data block from a transmitter to a receiver.
Referring also to
It should be appreciated that the logical flow of steps shown in
In accordance with a non-limiting example of a computer program product, a data processor is operated so as to make a determination that at least one criterion is fulfilled, and to transmit a current data block and to preemptively re-transmit the data block, at least once, to a receiver using one of, for example, the consecutive or parallel re-transmission schemes described above.
In accordance with a non-limiting example of an apparatus, a device includes a unit to make a determination that at least one criterion is fulfilled, and a unit to transmit a current data block and to preemptively re-transmit the data block, at least once, to a receiver using one of, for example, the consecutive or parallel re-transmission schemes described above.
In accordance with a further non-limiting example of an apparatus, an electronic device includes: processing means for determining whether at least one criterion is fulfilled; first transmission means for transmitting a data block to a receiver of another electronic device; and second transmission means for preemptively re-transmitting the data block to the receiver of the other electronic device in response to the processing means determining that the at least one criterion is met. In other exemplary embodiments, the processing means comprises a data processor, the first transmission means comprises a transmitter and the first transmission means comprises the second transmission means. In further exemplary embodiments, preemptively re-transmitting the data block comprises using one of a consecutive re-transmission scheme or a parallel re-transmission scheme. In other exemplary embodiments, the electronic device comprises one of a mobile station or a base station.
The exemplary embodiments of the invention, as discussed above and as particularly described with respect to exemplary methods, may be implemented as a computer program product comprising program instructions embodied on a tangible computer-readable medium. Execution of the program instructions results in operations comprising steps of utilizing the exemplary embodiments or steps of the method.
While the exemplary embodiments have been described above in the context of the (E)GPRS system, it should be appreciated that the exemplary embodiments of this invention are not limited for use with only this one particular type of wireless communication system, and that they may be used to advantage in other wireless communication systems.
In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the exemplary embodiments of this invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
The exemplary embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.
Programs, such as those provided by Synopsys, Inc. of Mountain View, Calif. and Cadence Design, of San Jose, Calif. automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or “fab” for fabrication.
Various modifications and adaptations to the foregoing exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. For example, re-transmission schemes other than the consecutive/parallel schemes as described above may employed. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this invention.
Furthermore, some of the features of the various non-limiting and exemplary embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.
This patent application claims priority under 35 U.S.C. §119(e) from Provisional Patent Application No. 60/815,065, filed Jun. 19, 2006, the disclosure of which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60815065 | Jun 2006 | US |
