Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
  • H04W16/24—Cell structures
  • H04W16/28—Cell structures using beam steering
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation

Definitions

• the present invention relates to a method for improving the quality of service of a cellular telecommunication network and allowing for new types of subscriptions.
• a first performance limitation due to re-using the same frequency band in each cell which causes a significant drop of performance levels (e.g. signal to interference and noise ratio, user throughputs) at crossing cells or sector edges wherein different radio signals, generated by the same or different base stations, might interfere one with each other.
• performance levels e.g. signal to interference and noise ratio, user throughputs
• a second performance limitation due to in-door performance levels e.g. signal to interference and noise ratio, user throughputs
• in-door performance levels e.g. signal to interference and noise ratio, user throughputs
• wireless networks are traditionally designed to provide outdoor coverage while indoor coverage is offered only to limited areas (e.g. up to 10dB to 20dB extra losses are afforded within buildings, which quite often is not enough to propagate deep inside buildings).
• This method is also known as fractional frequency reuse.
• the "capacity solution” which is based on increasing the number of cells. It has been observed by simulation experiments that without specific methods aimed at limiting the interference, by decreasing the inter- site distance the individual site capacity is decreased as well, resulting in an overall loss in system capacity.
• the present invention is directed to a method for improving the quality of service and the quality of experience offered by a cellular telecommunication network, mainly by controlling more efficiently cell edge interferences.
• the present invention relates to a method for improving the quality of service of a cellular telecommunication network wherein cells are irradiated by radio beams generated by base stations, each base station comprising means to irradiate at different time different areas of an associated cell by forming different radio beams, characterized in that it comprises the step of synchroniz- ing a first sequence of radio beams, generated by a first base station, with at least one other sequence of radio beams, generated by at least one other base station, in order to limit the radio interferences between said first base station and said at least one other radio-adjacent base station.
• the invention describes a simple and efficient method to provide a more uniform quality of service and quality of experience to the end users, since radio beams sequences can be generated in a way that completely or partially avoid interferences as described thereafter.
• the synchronization of said first base station's radio beams sequence with said at least one other base station's radio beams sequence comprises the step for both said first base station and said at least one other base station of following predetermined sequences of radio beams generation according to predetermined schedules and patterns.
• the predetermined radio beam schedules and patterns are modified depending on quality of service reports received by said first base station and/or said at least one other base station.
• the quality of service reports are generated by said first base station, said at least one other base station and/or by mobile terminals.
• said first base station and said at least one other base station transmit to each other received communications from mobile terminals in order to implement coordinated multi-site MIMO communications.
• MO communications Depending on a level of radio interferences between base stations.
• the number and/or the patterns of radio beam(s) formed by said first base station and/or said at least one other base station are modified depending on a level of radio interference between said first base station and said at least one other base station.
• the radio beams are adjusted in elevation.
• the invention also relates to a base station for a cellular telecommunication network wherein cells are irradiated by radio beams generated by base stations, each base station comprising means to irradiate at different time different areas of an associated cell by forming different radio beams, characterized in that it comprises means for synchronizing a first sequence of radio beams with at least one other sequence of radio beams, generated by at least one other base station, in order to limit its radio interferences with said at least one other base station following a method according to any of the previous embodiments.
• the invention also relates to a cellular telecommunication network comprising cells irradiated by radio beams generated by base stations, each base station comprising means to irradiate at different time different areas of an associated cell by forming different radio beams, characterized in that it comprises means for synchronizing a first sequence of radio beams, generated by a first base station, with at least one other sequence of radio beams, generated by at least one other base station, in order to limit the radio interferences between said first base station and said at least one other base station following a method according to any of the previous embodiments.
• FIG. 1 , 2, 3 and 4 are radio beam diagrams of a first base station implementing one embodiment of the invention.
• a first base station 100 might be able to generate, or activate, one or more different radio beams 102, 104, 106, 108, 1 10 or 1 12 at different time, each radio beam irradiating a different area of an associated cell.
• each radio beam is associated with a central azimuth, or horizontal angle, as summarized in the table herein below:
• the maximum number of radio beams can be any positive integer number as long as it is technologically feasible and justifiable by the level of system performance.
• the radio beams are adjusted in elevation i.e. perpendicularly to the horizontal surface in order to adapt their generation to the environment. Indeed, this adaptation might be done con- sidering the high level of scattering which exists in urban and in indoor environments.
• the base station 100 comprises means to activate different number of radio beams simultaneously as represented in figure 2, 3 or 4 for, respectively, one, three and six radio beams.
• the beams which are illuminated are represented by shaded areas in all these figures.
• said first base station 100 comprises means to synchronize a first sequence of radio beams with at least one other sequence of radio beams generation, performed by at least one other base station which may irradiate an area overlapping an area irradiated by the said first base station 100. Thereafter, such at least one other base sta- tion might be called radio-adjacent base station.
• the first sequence of radio beams associated with the first base station 100 and the at least one other sequence of radio beams associated with the at least one other base station 120 are identical and comprise seven periods:
• such a sequence of predetermined radio beams - defined by schedule(s) and pattern(s) - can be implemented in order to provide, during the first period, a general service to all mobile terminals within cells 101 and 201 associated to, respectively, base stations 100 and 120.
• the base stations 100 and 120 provide successively a specific service to specific areas as 103 or 203 (fig- ure 6) and, thereafter, 105 or 205 (figure 7), said specific areas not being adjacent so that edge interference is considerably reduced or rendered practically inexistent.
• radio beams 103 and 203, or 105 and 205 do not present common crossing edges for simplifying illustration purposes even if, due to radio propagation properties and scattering properties of the radio environments, it is possible to observe some level of interference across some geographical area where radio beams 103 and 203 still overlap.
• interference levels are expected to be considera- bly lower compared to scenarios where base stations 100 and 120 would radiate according to an omni-directional pattern for instance.
• the predetermined beam schedules and patterns - e.g. form, deepness and/or wideness of the radio beam- can be modified depending on quality of service reports received by the said first base station and/or the said at least one other radio-adjacent base station.
• quality of service reports generated by the said first base station, the said at least one other radio-adjacent base station and by mobile terminals are taken into account by each base station.
• each base station might generate a database indicating different beam interference levels with other base stations.
• multiple interference levels can be categorized so that, in a simplified approach, three different interference levels are considered, namely L for Low, M for Medium and H for high
• the radio beam sequences might also consider the interference database from adjacent - or neighboring - base sta- tions to determine the sequences of radio beams to be generated.
• such consideration is performed automatically by each base station so that it can dynamically adapt the radio beam sequence, e.g. to deliver a given quality of service.
• the beam switching sequence can be also formed by sub-bands (i.e. fractions of the used radio carrier bandwidth). Usually, the number of sub- bands is determined by propagation, channel response, or is specified by standards. An example is shown below for a case of four sub-bands.
• the radio beam sequence for sub-band 1 is [all, 1 , 1 ,
• the said first base station and the said at least one other radio-adjacent base station might transmit to each other received communications of mobile terminals in order to implement a coordinated multi-site MIMO communications network.
• At least three types of sequences of radio beams are considered by said first base station and said at least one other radio- adjacent base station, namely:
• a third type of radio beams wherein a multi-site MIMO communications network is considered.
• the first type of sequencing is the easiest to im- plement and the third level is the most complex so that their implementation might be operated successively according to different levels of interference.
• increasing levels of interference will correspond to increasing levels of complexity in the implemented type of sequence.
• the number and/or the patterns of radio beam(s) formed by the said first base station are modified depending on the level of radio interference.
• each base station has means to modify automatically its radio beam generations to limit radio beam interferences.
• radio beam patterns are adjusted dynamically according to, for instance, evolution of traffic and user mobility, topology of the covered area, nature of scattering environment, non uniformity of traffic.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=42078958

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (3)

Citations (5)

Family Cites Families (3)

• 2009
  • 2009-11-03 EP EP09174961.4A patent/EP2317789B1/en not_active Not-in-force
• 2010
  • 2010-10-29 KR KR1020127014131A patent/KR101458776B1/ko not_active Expired - Fee Related
  • 2010-10-29 WO PCT/EP2010/066529 patent/WO2011054768A1/en not_active Ceased
  • 2010-10-29 CN CN201080049420.9A patent/CN102598755B/zh not_active Expired - Fee Related
  • 2010-10-29 US US13/505,523 patent/US20130017824A1/en not_active Abandoned
  • 2010-10-29 BR BR112012010383A patent/BR112012010383A2/pt not_active IP Right Cessation
  • 2010-10-29 JP JP2012535860A patent/JP5653445B2/ja not_active Expired - Fee Related

Patent Citations (5)

Also Published As

Similar Documents

Legal Events