Random access channel enhancements for LTE devices

• US 9,215,701 B2
• Filed: 09/28/2012
• Issued: 12/15/2015
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Koc, Ali Taha, Phuyal, Umesh
• Primary Examiner(s): Sefcheck, Gregory
• Assistant Examiner(s): ULYSSE, JAEL M
• Application Number:
  US13/629,928
• Publication Number:
  US 20130242735A1
• Time in Patent Office: 1,173 Days
• Field of Search: 370/232, 370/235, 370/312, 370/328, 370/329, 455/450
• US Class Current: 1/1
• CPC Class Codes: H04J 11/0073 Acquisition of primary synchronisation channel, e.g. detection of cell-ID within cell-ID group
• CPC Class Codes: H04L 1/0033 arrangements specific to the transmitter
• CPC Class Codes: H04L 1/0077 Cooperative coding
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1635 Cumulative acknowledgement, i.e. the acknowledgement message applying to all previous messages
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 1/1864 ARQ related signaling H04L1/1607 takes precedence
• CPC Class Codes: H04L 1/1877 for semi-reliable protocols, e.g. for less sensitive applications like streaming video buffer level management for video bitstream control arrangements H04N21/44004
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/189 Transmission or retransmission of more than one copy of a message
• CPC Class Codes: H04L 1/1896 ARQ related signaling
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/6275 based on priority
• CPC Class Codes: H04L 5/001 : the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0053 : Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0055 : Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/0073 : Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04L 5/14 : Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1438 : Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001
• CPC Class Codes: H04L 5/1446 : of transmission speed
• CPC Class Codes: H04L 5/1469 : using time-sharing
• CPC Class Codes: H04L 65/75 : Media network packet handling
• CPC Class Codes: H04L 65/752 : adapting media to network capabilities
• CPC Class Codes: H04L 65/756 : adapting media to device capabilities
• CPC Class Codes: H04L 67/02 : based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/568 : Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04N 21/25841 : involving the geographical location of the client retrieval from the Internet by querying based on geographical locations G06F16/9537; arrangements for identifying locations of receiving stations in broadcast systems H04H60/51; location of the user terminal in data switching networks H04L67/52; services making use of the location of users or terminals in wireless networks H04W4/02; locating users or terminals in wireless networks H04W64/00
• CPC Class Codes: H04N 21/41407 : embedded in a portable device, e.g. video client on a mobile phone, PDA, laptop constructional details of equipment or arrangements specially adapted for portable computer application G06F1/1626; arrangements specially adapted for mobile receivers in broadcast systems H04H20/57
• CPC Class Codes: H04N 21/6405 : Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6408 : Unicasting
• CPC Class Codes: H04W 16/04 : Traffic adaptive resource partitioning
• CPC Class Codes: H04W 24/00 : Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/02 : Arrangements for optimising operational condition
• CPC Class Codes: H04W 28/0236 : radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 28/0268 : using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] negotiating SLA or negotiating QoS H04W28/24
• CPC Class Codes: H04W 28/0278 : using buffer status reports dynamic wireless traffic scheduling definition H04W72/12
• CPC Class Codes: H04W 4/06 : Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 52/02 : Power saving arrangements in wired systems H04L12/12; signaling of mobile application services, e.g. low battery notifications H04W4/20
• CPC Class Codes: H04W 52/0206 : in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/0209 : in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: H04W 52/0229 : where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0235 : where the received signal is a power saving command
• CPC Class Codes: H04W 52/143 : Downlink power control
• CPC Class Codes: H04W 52/243 : taking into account interferences
• CPC Class Codes: H04W 72/04 : Wireless resource allocation
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/12 : Wireless traffic scheduling
• CPC Class Codes: H04W 72/1268 : of uplink data flows
• CPC Class Codes: H04W 72/1273 : of downlink data flows
• CPC Class Codes: H04W 72/20 : Control channels or signalling for resource management
• CPC Class Codes: H04W 72/21 : in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/27 : between access points
• CPC Class Codes: H04W 72/51 : based on terminal or device properties
• CPC Class Codes: H04W 72/541 : using the level of interference
• CPC Class Codes: H04W 72/569 : of the traffic information
• CPC Class Codes: H04W 74/085 : collision avoidance
• CPC Class Codes: H04W 76/27 : Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 76/28 : Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Described herein is a technique for aggregating background traffic packets by the background users instead of performing a random access procedure to request an uplink resource for each new packet. Since the same physical random access channel (PRACH) resources are used for random access procedures by multiple UEs, collisions can occur. The PRACH is expected to operate with very low collision rates, but if the number of users increases, the collision rate increases as well as the error rate. The disclosed technique reduces the collision rate by reducing the number of random access procedures used to transmit background traffic.

Claims

1. A device operating as user equipment (UE) in a Long Term Evolution LTE network, comprising:

an RF transceiver for providing an LTE air interface for communicating with a base station operating as an enhanced/evolved Node B (eNB);

processing circuitry interfaced to the RF transceiver and arranged to, when not connected to the eNB so that no PUCCH (physical uplink control channel) resources have been allocated for transmitting scheduling requests and when a packet aggregation mode is entered;

start a packet aggregation timer;

inhibit the UE from transmitting on a physical random access channel (PRACH) for the purpose of transmitting uplink packets having a relaxed latency requirement, referred to as background packets, until expiration of the packet aggregation timer;

buffer the background packets; and

,

upon expiration of the packet aggregation timer, request uplink resources from the eNB via a random access procedure to transmit the buffered packets.

2. The device of claim 1, wherein the processing circuitry is arranged to reset the packet aggregation timer to a stored packet aggregation timer initialization value after expiration.

3. The device of claim 2, wherein the processing circuitry is to receive the packet aggregation timer initialization value from the eNB and store the received value.

4. The device of claim 3, wherein the processing circuitry is configured to request a lesser packet aggregation timer initialization value from the eNB if a rate at which background packets are being received for transmission exceeds a specified threshold.

5. The device of claim 3, wherein the processing circuitry is to enter a background packet aggregation mode in which background packets are buffered upon receiving a positive packet aggregation timer initialization value from the eNB.

6. The device of claim 5, wherein the processing circuitry is to exit the background packet aggregation mode upon receiving a command to do so from the eNB.

7. The device of claim 6, wherein the command from the eNB to exit the background packet aggregation mode is a zero packet aggregation timer initialization value.

8. The device of claim 1, wherein the processing circuitry is to enter a background packet aggregation mode in which background packets are buffered if a rate at which random access procedures are being performed for transmitting background traffic exceeds a specified threshold.

9. The device of claim 1, further comprising:

a battery charge indicator; and

wherein the processing circuitry is to enter a background packet aggregation mode in which background packets are buffered if the battery charge indicator indicates a low power state.

10. The device of claim 1, wherein the processing circuitry is to enter a background packet aggregation mode in which background packets are buffered upon receipt of a user command via a user input.

11. The device of claim 1, wherein the processing circuitry is to request uplink resources from the eNB for transmitting the buffered background packets prior to expiration of the packet aggregation timer if the number of background packets that have been buffered exceeds a specified threshold.

12. The device of claim 3, wherein the processing circuitry is to restart the packet aggregation timer if a new packet aggregation timer initialization value is received from the eNB.

13. The device of claim 3, wherein the processing circuitry is to receive the packet aggregation timer initialization value in a master information block (MIB) sent by the eNB.

14. The device of claim 3, wherein the processing circuitry is to receive the packet aggregation timer initialization value in a system information block (SIB) sent by the eNB.

15. A method for operating user equipment (UE) in a Long Term Evolution LTE network, comprising:

if a packet aggregation mode is enabled and the UE is not connected to the eNB so that no PUCCH (physical uplink control channel) resources have been allocated for transmitting scheduling requests to the eNB;

inhibiting the UE from transmitting on a physical random access channel (PRACH) for the purpose of transmitting uplink packets having a relaxed latency requirement, referred to as background packets, until expiration of the packet aggregation timer,

starting a packet aggregation timer;

buffering the background packets;

upon expiration of the packet aggregation timer, requesting uplink resources from the eNB for transmitting the buffered background packets via a random access procedure and transmitting the buffered background packets on the allocated uplink resources.

16. The method of claim 15, further comprising resetting the packet aggregation timer to a stored packet aggregation timer initialization value after expiration.

17. The method of claim 16, further comprising receiving the packet aggregation timer initialization value from an eNB and storing the received value.

18. The device of claim 15, further comprising entering the background packet aggregation mode if the rate at which random access procedures are being performed for transmitting background traffic exceeds a specified threshold.

19. The device of claim 15, further comprising entering the background packet aggregation mode if the battery charge indicator indicates a low power state.

20. The device of claim 15, further comprising entering the background packet aggregation mode upon receipt of a user command via a user input.

21. The device of claim 15, further comprising, if the background packet aggregation mode is enabled, requesting uplink resources from the eNB for transmitting the buffered background packets prior to expiration of the packet aggregation timer if the number of background packets that have been buffered exceeds a specified threshold.

22. A method for operating an evolved node B (eNB) in an LTE network, comprising:

detecting a collision rate among UEs in accessing the physical random access channel (PRACH); and

if the detected collision rate exceeds a specified threshold, transmitting a command to user equipment (UE) that the UEs enter a background packet aggregation mode in which the UEs are configured to, when not connected to the eNB so that no PUCCH (physical uplink control channel) resources have been allocated for transmitting scheduling requests and when a packet aggregation mode is entered;

start a packet aggregation timer;

inhibit the UE from transmitting on a physical random access channel (PRACH) for the purpose of transmitting uplink packets having a relaxed latency requirement, referred to as background packets, until expiration of the packet aggregation timer;

buffer the background packets; and

,

upon expiration of the packet aggregation timer, request uplink resources from the eNB via a random access procedure to transmit the buffered packets.

23. The method of claim 22, further comprising transmitting the command to enter the background packet aggregation mode in a master information block (MIB).

24. The method of claim 22, further comprising transmitting the command to enter the background packet aggregation mode in a system information block (SIB).