Batik

Title: Batik

Composer:  Koko Koswara

Artist: Nano S

samping batik ngandung wanda

sinarna geus suda suda

dikampung-kampung di kota

nambah komara wanita

siep diteuteup mojang kiwari

ringsing di tilik kawanti-wanti

lambang ngandung pelet batik pereng bayonet

matak bengong nu ngareret ejeug milo

robah jaman ngarekahan

jadi mode kalakonan

sawarnaning papakean

tulis batik ditumpalan

mega mendungan batik cirebon

tulis nu asli motif kembangan

setelan kabaya aduh manis dangdosan

nambah asri nu nganggona cahayaan

batik corak nasional

hargana teu pati mahal

usahana panteng gagal

kiwari internasional

batik nu narik buatan tasik

batik nu manis ngan ti ciamis

batik los kumbara najong ka amerika

nambah sakuliah dunya tatalepa

samping batik babar sawit

sari na moal rek leungit

erok batik make dansa

corelak nambah cahaya

keur panas poe ereng-erengan

hatur dangdosan keur papanasan

rok batik sacewir tonggong leungeun buligir

kapanasan rada nyegir usum batik

batik teu kateler-teler

kiwari jadi populer

teu ungkul di indonesia

tapi sakuliahun

kameja koboi aya baturna

kameja batik masieup kota

piyama ku batik sarung angel ku batik

jubah jeung gardeng ku batik kabeh batik

midang ginding make batik

henteu ngan ungkul di tasik

tapi meh di unggal kota

pakean sagala bangsa

sagala batik teu ya di kota

sumanget batik dimana-mana

kimono ku batik mode show tina batik

kulit sapatu ku batik kabeh batik

Standar Prosedur Penggantian Frekuensi BS Aperto PacketWave

Contoh kasus:

Penggantian frekuensi pada BS WSS-4

Frekuensi asal: 2687 MHz

Frekuensi baru: 2680 MHz

Tahapan penggantian:

1. Pastikan frekuensi pengganti benar-benar bersih.

2. Browse semua CPE yang terhubung ke WSS/ sector terkait (misal IP salah satu CPE: 10.4.65.15).

3. Isi kolom Frequency Table (MHz) di tiap-tiap CPE dengan nilai frekuensi yang baru pada menu Configuration \ Wireless Interface \ Frequency Table (MHz).

4. Klik Submit \ Configuration Upload \ Configuration Upload \ OK.

5. Browse BSU yang akan diganti frekuensinya (misal IP BSU: 10.4.65.1).

6. Masuk ke menu Configuration \ Wireless Interface \ < port number> Frequency.

7. Isi kolom Frequency Table (MHz) di BSU dengan nilai frekuensi yang baru.

8. Klik Submit >> Configuration Upload >> Configuration Upload \ OK.

9. Masuk kembali ke menu Configuration \ Wireless Interface \ <port number> Frequency .

10. Klik Switch Frequency.

11. Klik nilai frekuensi yang baru kemudian klik Switch Frequency.

12. Kembali ke menu Configuration \ Wireless Interface \ <port number> Frequency.

13. Ganti Target Frequency (MHz) dengan nilai frekuensi yang baru.

14. Klik Submit \ Configuration Upload \ Configuration Upload \ OK.

15. Ganti nilai Target Frequency (MHz) di tiap CPE dengan nilai frekuensi yang baru, Current SU Frequency (MHz).

16. Klik Submit \ Configuration Upload \ Configuration Upload \ OK.

17. Proses penggantian frekuensi selesai.

RF Signal Quality – No Energy Count (No Energy Error)

No energy error counters when scheduled packet did not arrive, or arrived with very low power level (below the minimum energy level threshold).

 

@ BSU: error count increases for each frame that does not have contention traffic. NORMAL

 

@ SU: Numerous NO ENERGY errors usually indicate a VERY low signal level. SU should be pointed again.

 

Troubleshooting should be performed via Web GUI

Aperto Subscriber Unit (SU) Issues

SU Synchronization Issues

• Incorrect Frequency
• Incorrect Channel Width
• Incorrect BSU ID
• BSU wireless port is not operational
• SU Indoor Unit failed to detect the Outdoor Unit
• SU antenna is not pointed correctly
• The SU is out of range from the BSU and is not able to receive any signal from the BSU

 

SU DHCP Issues

• The DHCP Server may not have the correct reservation for the SU
• The DHCP Server may be not operational
• The SU DHCP Server entry on the BSU may not be configured correctly
• If multiple subnets are configured within the wireless port serving the SU, the DHCP Super-scope should be defined properly

 

SU Configuration File Issues

• The TFTP Server IP address specified in the DHCP response may be invalid
• The default gateway specified in the DHCP response may be incorrect
• Missing route on the TFTP Server
• TFTP server application is not running
• The SU may have established a two way link on the wrong sector
• Bad wireless link (Upstream)
• Even after a successful download of the configuration file, the SU might reject the file due to version incompatibility

 

SU Registration Problems

• The SU configuration file specifies Service Flows for which the BSU does not have any reserved bandwidth
• If the SU configuration file specifies a larger number of classifiers
• Registration would also fail if the number of service flows configured for the SU did not match with the service flows configure for the WSS
• If the number of SUs registering exceeds the number of supported SUs configure in the BSU

Interference of Waves

As most commonly used, the term interference usually refers to the interaction of waves which are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency.

Wave interference is the phenomenon which occurs when two waves meet while traveling along the same medium. The interference of waves causes the medium to take on a shape which results from the net effect of the two individual waves upon the particles of the medium.

Consider two waves that are in phase,with amplitudes A₁ and A₂. Their troughs and peaks line up and the resultant wave will have amplitude A = A₁ + A₂. This is known as constructive interference — a type of interference which occurs at any location along the medium where the two interfering waves have a displacement in the same direction.

If the two waves are pi radians, or 180°, out of phase, then one wave’s crests will coincide with another wave’s troughs and so will tend to cancel out. The resultant amplitude is A = | A₁ − A₂ | . If A₁ = A₂, the resultant amplitude will be zero. This is known as destructive interference — a type of interference which occurs at any location along the medium where the two interfering waves have a displacement in the opposite direction.

When two sinusoidal waves superimpose, the resulting waveform depends on the frequency (or wavelength) amplitude and relative phase of the two waves. If the two waves have the same amplitude A and wavelength the resultant waveform will have an amplitude between 0 and 2A depending on whether the two waves are in phase or out of phase.

The task of determining the shape of the resultant demands that the principle of superposition is applied. The principle of superposition is sometimes stated as follows: When two waves interfere, the resulting displacement of the medium at any location is the algebraic sum of the displacements of the individual waves at that same location.

OFDM Basics

Orthogonal frequency division multiplexing (OFDM) belongs to a family of transmission schemes called multicarrier modulation, which is based on the idea of dividing a given high-bit-rate data stream into several parallel lower bit-rate streams and modulating each stream on separate carriers—often called subcarriers, or tones. Multicarrier modulation schemes eliminate or minimize inter-symbol interference (ISI) by making the symbol time large enough so that the channel-induced delays—delay spread being a good measure of this in wireless channels—are an insignificant (typically, <10 percent) fraction of the symbol duration. Therefore, in high-data-rate systems in which the symbol duration is small, being inversely proportional to the data rate, splitting the data stream into many parallel streams increases the symbol duration of each stream such that the delay spread is only a small fraction of the symbol duration.

OFDM is a spectrally efficient version of multicarrier modulation, where the subcarriers are selected such that they are all orthogonal to one another over the symbol duration, thereby avoiding the need to have non-overlapping subcarrier channels to eliminate inter-carrier interference. Choosing the first subcarrier to have a frequency such that it has an integer number of cycles in a symbol period, and setting the spacing between adjacent subcarriers (subcarrier bandwidth) to be BSC = B/L, where B is the nominal bandwidth (equal to data rate), and L is the number of subcarriers, ensures that all tones are orthogonal to one another over the symbol period. It can be shown that the OFDM signal is equivalent to the inverse discrete Fourier transform (IDFT) of the data sequence block taken L at a time. This makes it extremely easy to implement OFDM transmitters and receivers in discrete time using IFFT (inverse fast Fourier) and FFT, respectively.

In order to completely eliminate ISI, guard intervals are used between OFDM symbols. By making the guard interval larger than the expected multipath delay spread, ISI can be completely eliminated. Adding a guard interval, however, implies power wastage and a decrease in bandwidth efficiency. The amount of power wasted depends on how large a fraction of the OFDM symbol duration the guard time is. Therefore, the larger the symbol period—for a given data rate, this means more subcarriers—the smaller the loss of power and bandwidth efficiency.

The size of the FFT in an OFDM design should be chosen carefully as a balance between protection against multipath, Doppler shift, and design cost/complexity. For a given bandwidth, selecting a large FFT size would reduce the subcarrier spacing and increase the symbol time. This makes it easier to protect against multipath delay spread. A reduced subcarrier spacing, however, also makes the system more vulnerable to inter-carrier interference owing to Doppler spread in mobile applications. The competing influences of delay and Doppler spread in an OFDM design require careful balancing.

WiMAX QoS

Support for QoS is a fundamental part of the WiMAX MAC-layer design. WiMAX borrows some of the basic ideas behind its QoS design from the DOCSIS cable modem standard. Strong QoS control is achieved by using a connection-oriented MAC architecture, where all downlink and uplink connections are controlled by the serving BS. Before any data transmission happens, the BS and the MS establish a unidirectional logical link, called a connection, between the two MAC-layer peers. Each connection is identified by a connection identifier (CID), which serves as a temporary address for data transmissions over the particular link. In addition to connections for transferring user data, the WiMAX MAC defines three management connectionsthe basic, primary, and secondary connectionsthat are used for such functions as ranging.

WiMAX also defines a concept of a service flow. A service flow is a unidirectional flow of packets with a particular set of QoS parameters and is identified by a service flow identifier (SFID). The QoS parameters could include traffic priority, maximum sustained traffic rate, maximum burst rate, minimum tolerable rate, scheduling type, ARQ type, maximum delay, tolerated jitter, service data unit type and size, bandwidth request mechanism to be used, transmission PDU formation rules, and so on. Service flows may be provisioned through a network management system or created dynamically through defined signaling mechanisms in the standard. The base station is responsible for issuing the SFID and mapping it to unique CIDs. Service flows can also be mapped to DiffServ code points or MPLS flow labels to enable end-to-end IP-based QoS. To support a wide variety of applications, WiMAX defines five scheduling services that should be supported by the base station MAC scheduler for data transport over a connection:

1. Unsolicited grant services (UGS): This is designed to support fixed-size data packets at a constant bit rate (CBR). Examples of applications that may use this service are T1/E1 emulation and VoIP without silence suppression. The mandatory service flow parameters that define this service are maximum sustained traffic rate, maximum latency, tolerated jitter, and request/transmission policy.
2. Real-time polling services (rtPS): This service is designed to support real-time service flows, such as MPEG video, that generate variable-size data packets on a periodic basis. The mandatory service flow parameters that define this service are minimum reserved traffic rate, maximum sustained traffic rate, maximum latency, and request/transmission policy.
3. Non-real-time polling service (nrtPS): This service is designed to support delay-tolerant data streams, such as an FTP, that require variable-size data grants at a minimum guaranteed rate. The mandatory service flow parameters to define this service are minimum reserved traffic rate, maximum sustained traffic rate, traffic priority, and request/transmission policy.
4. Best-effort (BE) service: This service is designed to support data streams, such as Web browsing, that do not require a minimum service-level guarantee. The mandatory service flow parameters to define this service are maximum sustained traffic rate, traffic priority, and request/ transmission policy.
5. Extended real-time variable rate (ERT-VR) service: This service is designed to support real-time applications, such as VoIP with silence suppression, that have variable data rates but require guaranteed data rate and delay. This service is defined only in IEEE 802.16e-2005, not in IEEE 802.16-2004. This is also referred to as extended real-time polling service (ErtPS).

Although it does not define the scheduler per se, WiMAX does define several parametersand features that facilitate the implementation of an effective scheduler:

• Support for a detailed parametric definition of QoS requirements and a variety of mechanisms to effectively signal traffic conditions and detailed QoS requirements in the uplink.
• Support for three-dimensional dynamic resource allocation in the MAC layer. Resources can be allocated in time (time slots), frequency (subcarriers), and space (multiple antennas) on a frame-by-frame basis.
• Support for fast channel-quality information feedback to enable the scheduler to select the appropriate coding and modulation (burst profile) for each allocation.
• Support for contiguous subcarrier permutations, such as AMC, that allow the scheduler to exploit multiuser diversity by allocating each subscriber to its corresponding strongest sub-channel.

It should be noted that the implementation of an effective scheduler is critical to the overall capacity and performance of a WiMAX system.

 

Source: Fundamentals of WiMAX : understanding broadband wireless networking / Jeffrey G. Andrews, Arunabha Ghosh, Rias Muhamed. PrenticeHall. 2007.

Standard Operating Procedure – BSR Stopped Issue

Gambar di bawah ini menerangkan proses penanganan masalah jika diketahui BSU Radio Status adalah Stopped:

Prosedur di atas dibuat berdasarkan data dan pengalaman di lapangan.

89 – Code:1 Task SUSP tWCx

The “89 – Code:1 Task SUSP tWCx” is a minor error code and will not affect the system’s performance. This error code refers to a delay in execution of a task; however, once the delay or a single instance is triggered, the error code is reported continuously, regardless of whether the condition is there or not.

 

This error code is not related the SU’s / BSU’s ability to communicate with one another.

To stop the continuing reporting of this error, you can either schedule a reboot of the BSU by using telnet services or console the BSU.

Burst Error Rate (BER)

Burst error rate, BER, is cumulative ratio of burst errors to total number of received bursts in percentage format.

BER Includes:

- Uncorrectable FEC

Uncorrectable FEC (forward error correction) is a condition where valid burst was received and demodulated; however, there were more errors in the burst than could be corrected by the FEC.

High number of uncorrectable FEC caused by:

o low SNR (link is too long),

o multipath fading

o Interference

- No Unique Word

No Unique Word Count indicates that some energy was detected (above the minimum power threshold) during a scheduled time slot, however no Unique Word was detected.

The Unique Word is an identifier that is part of the preamble of every wireless burst and must be valid in order for a burst to be properly demodulated.

No UW on the BSU caused by interference or collisions during contention requests

No UW on the SU caused by Interference or radio too close to base (signal should be less than –45dBm)

- No Energy errors

No energy error is when scheduled packet did not arrive, or arrived with very low power level (below the minimum energy level threshold).

On the BSU: error count increases for each frame that does not have contention traffic. This is a normal condition.

On the SU: Numerous NO ENERGY errors usually indicate a VERY low signal level. SU should be pointed again

BSU in a good condition have an errors < 1-2%. BSU with errors < 5 % is still accepted.

High rate BER indicates interference.

What should we do if we found that BER counter more than 5%?

1. Reset the BSU radio status counter.
2. Step up the Rx power of the BSU (up to -60 dBm).
3. Scan the frequency using the FSA tools that belong to the BSU.
4. Switch the frequency.