Methods and Apparatus for Cellular Broadcasting and Communication System

• US 20080198785A1
• Filed: 03/24/2006
• Published: 08/21/2008
• Est. Priority Date: 05/01/2004
• Status: Active Grant

• Current Assignee: Neo Wireless LLC (f/k/a CFIP NCF LLC) (SoftBank Group Corp.)
• Original Assignee: Neocific Incorporated
• Inventors: Lo, Titus, Huang, Haiming, Li, Xiaodong, Li, Kemin
• Granted Patent: US 8,089,911 B2
• Time in Patent Office: Days
• US Class Current: 370/312
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 12/1881 with schedule organisation, e.g. priority, sequence management
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04N 21/2385 Channel allocation H04N21/266 takes precedence; Bandwidth allocation H04N21/24 takes precedence ; allocation of channels according to the instantaneous demands of the users in time-division multiplex systems H04J3/1682; admission control, resource allocation in open networks H04L12/5692; arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896; negotiating bandwidth in wireless networks H04W28/16
• CPC Class Codes: H04N 21/26208 the scheduling operation being performed under constraints
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/6131 involving transmission via a mobile phone network wireless downlink channel access H04W74/006
• CPC Class Codes: H04N 21/6582 Data stored in the client, e.g. viewing habits, hardware capabilities, credit card number arrangements where receivers interact with the broadcast H04H20/38
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a cellular wireless network, methods and apparatus are disclosed for a signal broadcasting scheme that can be individually augmented for users with poor reception. The network employs a first downlink channel (broadcast CH) for broadcasting data to all mobile stations (S1, S2, S3), a second downlink channel (regular CH) for sending signals to a specific mobile station in a cell, and an uplink channel for feeding back information to the base station. To achieve a certain user reception quality, the system adjusts its broadcasting parameters based on the statistical analysis of the feedback data (feedback). If some users still require better reception, the system individually augments their broadcast signals via the second downlink channels. Methods and apparatus are also disclosed for synchronization of data distribution by base stations (1,2), which, in part, allows the receivers to combine the receiving signals and improve their reception quality.

Claims

1. A method of data broadcasting in a cellular communication network of base stations and mobile stations, the method comprising:

broadcasting signals via a broadcast downlink channel from at least one base station to multiple mobile stations;

sending signals in a cell via a downlink regular channel, from the base station to an individual mobile station, wherein;

each downlink regular (unicast) channel is allocated to one individual mobile station for downlink communication with the cell base station; and

the downlink regular channel is used to enhance the broadcast quality;

sending signals in a cell via an individual uplink channel, from a mobile station to the cell base station, wherein;

each individual uplink channel is assigned to one individual mobile station for uplink communication with the base station; and

the individual mobile station sends data, application requests, feedback information, or a combination thereof, to the base station via the assigned uplink channel;

making decisions on a necessity and manner of individual signal augmentation or repetition, based on the request or feedback information from individual mobile stations; and

sending augmenting signals or repeating signals via the downlink regular channel, from the base station to the individual mobile stations, if a decision is made to do so.

2. The method of claim 1, wherein the two downlink channels have different characteristics, and wherein:

the downlink broadcast channel is allocated in a specific time period or frequency spectrum or both, and the broadcast signals are transmitted to the entire cell or a sector, and wherein;

a default modulation and coding scheme (MCS) of the downlink broadcast channel is selected through a pre-deployment site survey or a cellular network planning; and

multiple base stations may transmit the same broadcast signals in a coordinated manner; and

the downlink regular channel is allocated in other specific time period or frequency spectrum or both, and the unicast signal can be transmitted via a narrow-beam to a specific mobile station, and wherein the MCS and transmit power can be adaptive based on channel quality index (CQI) information.

3. The method of claim 1, wherein:

the feedback information comprises mobile station requests, ACK/NACK for downlink data packets, broadcast downlink channel quality information of each individual mobile station, downlink regular channel quality information of each individual mobile station, or a combination thereof; and

channel quality feedbacks are updated by the mobile stations, via the individual uplink channels either periodically, when being polled by the base station, or when triggered by a predefined system event or threshold.

4. The method of claim 1, wherein the cellular network uses an adaptable frame structure (AFS) that has a video subframe and a data subframe, and wherein:

the video subframe is used as the downlink broadcast channel and the data subframe includes a downlink period that is used as the downlink regular channel and an uplink period that is used for transmitting individual uplink feedback information;

the video subframe uses a single frequency network (SFN) to simultaneously broadcast same radio signals from the base stations;

or

the cellular network uses a combination thereof.

5. The method of claim 1, wherein in multimedia applications, application data are encoded into multiple bit streams using an encoding scheme, and wherein some bit streams are transmitted via broadcast downlink channel and other bit streams are transmitted via downlink regular channels.

6. The method of claim 5, wherein application data are encoded using:

video-quality-based schemes, wherein a bit stream contains basic information or differential information;

signal-quality schemes, wherein a bit stream contains repetitive information of other bit streams;

medium-type-based schemes, wherein a bit stream contains voice information, video information, or text information;

schemes based on other principles;

or

the application data are encoded using a combination thereof.

7. The method of claim 5, wherein the multiple bit streams are mapped into the underlying two downlink radio channels by an intelligent scheduling agent (IMA), and wherein the mapping involves:

forwarding receiver feedbacks to the decision making database and updating the decision making database information, which include any combination of application information, wireless channel information, feedback information, or network management information;

consulting with a decision making database for system control information;

generating scheduling decisions based on system control information and objectives; and

multiplexing the bit streams into different channels based on the scheduling decisions.

8. The method of claim 7, wherein a Scheduler consults a Decision Making Database and uses its data as an input to a scheduling algorithm and decides whether the broadcast downlink channel and the downlink regular channel should be used for the data transmission, and if both channels are used, the incoming data is dispatched to channel message queues, and wherein the Scheduler determines a modulation and coding scheme (MCS) and transmission technologies used for the channels, and allocates an air link resource to both channels and the data is mapped into the underlying physical channels and transmitted to the mobile stations.

9. The method of claim 1, wherein in an adaptable frame structure (AFS) cellular system, the mobile station measures the channel quality using:

a common radio frequency (RF) receiver circuitry in a time-sharing fashion, wherein;

the broadcast downlink channel and the downlink regular channel occupy different subframes;

or

the broadcast downlink channel and the downlink regular channel are separated by different transmission times in a multiple frequency band system;

or

two or more radio frequency (RF) receiver circuits, wherein the broadcast downlink channel and the downlink regular channel are both used to transmit data simultaneously in a multiple frequency band system.

10. The method of claim 1, wherein a mobile station reports the channel quality of one or both downlink channels to the base station and the base station determines that a reported broadcast channel quality is insufficient and the base station at least adjusts modulation and coding scheme (MCS), Medium Access Control (MAC) resource allocation (time, frequency, subchannels), or power, or use beam forming, or a combination thereof, to send the signal to the mobile station in the corresponding downlink regular channel, and wherein the transmission parameters are specifically selected for said mobile station based on the channel quality report of the downlink regular channel.

11. A method of data broadcasting in a cellular communication network of base stations and mobile stations, wherein each base station provides signal coverage to a cell, the method comprising:

broadcasting signals in a plurality of cells, from a base station in each of the plurality of cells, via a broadcast downlink channel that is shared by multiple mobile stations, wherein;

the broadcast signals use an adaptable frame structure (AFS) wherein the AFS includes a transmission frame comprising a flexible mix of multiple subframe types where each subframe contains a downlink transmission period and an uplink transmission period; and

the broadcast signals are simultaneously transmitted by all the base stations using a common time/frequency resource;

receiving at each base station in the plurality of cells, via individual uplink channels, feedback information from individual mobile stations, wherein the feedback information at least partly characterizes the broadcast downlink channel quality, and wherein each individual uplink channel is assigned to one individual mobile station for uplink communication with the base station in the cell;

analyzing the feedback information from the mobile stations to determine a necessity and manner of adjusting broadcast signals, and a necessity and manner of augmenting individually received signals, based on the feedback information from corresponding individual mobile stations;

adjusting broadcast signals based on the analyzed feedback information; and

sending individual augmenting or repeating signals via downlink regular channels to individual mobile stations based on the analyzed individual feedback information, and wherein each downlink regular channel is assigned to an individual mobile station for downlink communication of the base station with the mobile stations in the cell.

12. A cellular broadcasting and communication system for use with mobile stations performing as user terminals, the system comprising:

base stations providing signal coverage to a cell, wherein at least one base station is configured to;

broadcast signals via a broadcast downlink channel that is received by multiple mobile stations;

receive, via an individual uplink channel, feedback information from an individual mobile station, wherein the feedback information at least partly characterizes a quality of the broadcast downlink channel, and wherein each individual uplink channel is assigned to one of the individual mobile stations for uplink communication with the base station in the cell;

adjust the broadcast signals based on an analysis of the feedback information; and

send augmenting or repeating broadcast signals via downlink regular channels to individual mobile stations when the feedback information from each of the individual mobile stations indicates unacceptable broadcast downlink channel quality or requests signal augmentation, wherein each downlink regular channel is assigned to a corresponding individual mobile station for downlink communication of the base station with the individual mobile stations in the call, and wherein;

the system operates as a packet data network with an adaptable frame structure (AFS) in which a transmission frame comprises a flexible mix of multiple subframe types, and each subframe contains a downlink transmission period and an uplink transmission period; and

the broadcasting signal is simultaneously transmitted by all the base stations using a common time/frequency resource.

13. The system of claim 12, wherein in multiple multimedia applications, application data is encoded into multiple application bit streams using a source coding scheme, and wherein for SFN (single frequency network) based broadcasts, original bit streams S1, S2, . . . , Sn, are first transmitted to control servers where the control servers attach time synchronization information to the streams and wherein modified streams are transmitted to the base stations via a backbone network to be used by the base stations to synchronize transmission times, and wherein the attached information is removed from the modified streams before the streams are broadcasted to the mobile stations.

14. A base station in a cellular data broadcasting and communication packet data network, wherein the base station employs an adaptable frame structure (AFS) where broadcasting signals are simultaneously transmitted by all base stations using a substantially similar time/frequency resource, the base station comprising:

a transmitter for broadcasting signals via a broadcast downlink channel shared by multiple mobile stations;

a receiver for receiving, via an individual uplink channel, feedback information from individual mobile stations, wherein the feedback information is at least partly regarding broadcast downlink channel quality, and wherein each individual uplink channel is assigned to one of the multiple mobile stations for uplink communication with the base station;

a decision-making facility for analyzing the feedback information, collectively and individually, and determining multiple aspects of compensating for channel quality deficiencies; and

a configuration wherein the transmitter adjusts broadcast signals and also sends individual compensating or repeating signals via downlink regular channels to selected individual mobile stations based on the collective and individual feedback information, respectively, and wherein each downlink regular channel is assigned to one of the multiple mobile stations for downlink communication of the base station with the individual mobile stations.

15. A data signal embodied in a carrier wave readable by a telecommunications system, the data signal comprising:

at least one downlink regular channel; and

at least one downlink broadcast channel, wherein;

the downlink broadcast channel is utilized for broadcasting signals that are received by multiple mobile stations;

the downlink regular channel is assigned to one mobile station for downlink communication of a base station with the mobile station in a cell, to repeat or augment an inadequate broadcast signal, and wherein repeating- or augmenting-signals are based on feedback information from the mobile station to the base station via an individual uplink channel; and

transmission frames comprise a flexible mix of multiple subframe types, and each subframe contains a downlink transmission period and an uplink transmission period.

16. A method of data broadcasting in a cellular communication network of base stations and mobile stations, wherein each base station provides signal coverage to a cell, and wherein a control server (CS) in the network controls at least one base station, the method comprising:

connecting the control server to the corresponding base stations via a packet distribution network (PDN) that is either a wired network or a wireless network;

overlaying a synchronized packet distribution network (SPDN) on the packet distribution network (PDN);

receiving original data packets by a Distribution Adapter (DA) of the SPDN and distributing the data packets across the PDN to the base stations after adding an additional protocol information, wherein the additional protocol information includes time synchronization information, resource scheduling information, application specific control information, protocol control information, or a combination thereof; and

ensuring a synchronized data transmission by the base stations via a Receiving Adapter (RA) that uses a same data content and a same time/frequency resource.